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Hindawi Publishing CorporationJournal o NanomaterialsVolume 983090983088983089983091 Article ID 983096983097983095983088983092983091 983089983088 pageshttpdxdoiorg983089983088983089983089983093983093983090983088983089983091983096983097983095983088983092983091

Research ArticleEffect of Ag-Nanoparticles Doped in Polyvinyl Alcohol onthe Structural and Optical Properties of PVA Films

Mahshad Ghanipour and Davoud Dorranian

Laser Laboratory Plasma Physics Research Center Science and Research Branch Islamic Azad University ehran Iran

Correspondence should be addressed to Davoud Dorranian ddorraniangmailcom

Received 983091983088 September 983090983088983089983091 Revised 983094 December 983090983088983089983091 Accepted 983097 December 983090983088983089983091

Academic Editor Amirkianoosh Kiani

Copyright copy 983090983088983089983091 M Ghanipour and D Dorranian Tis is an open access article distributed under the Creative CommonsAttribution License which permits unrestricted use distribution and reproduction in any medium provided the original work isproperly cited

Te effect o silver nanoparticlesdopedin PVA on thestructural andopticalpropertieso composite 1047297lmsis studied experimentallySamples are PVA 1047297lms o 983088983089983092 mm thickness doped with different sizes and concentrations o silver nanoparticles Structuralproperties are studied using X-ray diffraction and FIR spectrum Using the re1047298ectance and transmittance o samples the effecto doped nanoparticles and their concentration on optical parameters o PVA 1047297lms include absorption coefficient optical bandgapenergy complex reractive index complex dielectric unction complex optical conductivity and relaxation time is extracted anddiscussed Te dispersion o the reractive index o 1047297lms in terms o the single oscillator Wemple-DiDomenico (WD) model isinvestigated and the dispersion parameters are calculated Results show that by doping silver nanoparticles in PVA number o

Braggrsquos planes in the structure o polymer and its crystallinity are increased noticeably AgndashO bonds are ormed in the 1047297lms andthe bandgap energy o samples is decreased Calculations based on WD model con1047297rm that by doping nanoparticles the anionstrength o PVA as a dielectric medium is decreased

1 Introduction

Metal nanoparticles combined polymers attracted great con-sideration because o the widened application goal offeredby these hybrid materials [983089ndash983094] It is well established thatpolymers as dielectric materials are excellent host matricesor encapsulation o metal nanoparticles like silver goldcopper and so orth as they act both as reducing as well as

capping agents and also provide environmental and chemicalstability [983095ndash983097] At the same time these embedded nanopar-ticles inside the polymer matrix will also affect the prop-erties o the host itsel [983089 983094 983089983088ndash983089983091] Particularly polymer-metal hybrid such as polymer-Ag-nanoparticles compositesis promising unctional materials in several 1047297elds such asoptical electrical thermal mechanical and antimicrobialproperties [983089 983089983092ndash983089983096] Many reports in the literature show attempts or synthesis o metal nanoparticles based polymernanocomposites with the possibility o variation in theiroptical and electrical properties or their application inhigh perormance capacitors conductive inks and otherelectronic components [983090 983089983097 983090983088] For their application in

optoelectronic electrical and optical devices biomedicalscience sensors and so orth main key points are selectiono polymer-metal nanoparticles combination controlling theparticles size their concentration and distribution withinthe polymer matrix [983090 983090983089ndash983090983091] Special worthy has beenreached to optical properties o the nanoparticles doped inpolymer 1047297lm depending on the surrounding medium [983090983092ndash983090983094] and on their size shape and concentration [983090983095ndash983091983088]

Silver nanoparticles have received considerable attention dueto their attractive physical and chemical properties [983089] andit has been protected by polymers such as PVA PVP andPMMA PVA could be considered as a good host material ormetal due to its excellent thermostability chemical resistancehigh mechanical strength water solubility and moderateand dopant dependent electrical conductivity along with itsconsideration among the best polymers as host matrix orsilver nanoparticles [983089 983091983089] PVA can effectively protect thenanoparticles rom aggregation [983089 983097]

In this paper we ocus on the structural and opticalproperty variation o the supporting polymer due to silvernanoparticles doping Silver nanoparticles were produced

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983090 Journal o Nanomaterials

(a)

Pure PVA S1 S3S2

(b)

F983145983143983157983154983141 983089 (a) Ag nanoparticle samples in distilledwater and(b) purePVA polymer 1047297lm and Ag doped PVA 1047297lms

by laser ablation method Te laser ablation technique in aliquid produces proper metal nanoparticle samples to acili-tate investigation o their photophysical and photochemicalproperties [983091983090] A remarkable and advantageous eatureo nanoparticles prepared using this technique in contrastto those prepared using chemical synthesis is absence o uncontrolled byproducts [983091983090 983091983091] Interesting effects wereobserved on crystal structure and its optical properties Tenoticeable main variations o optical properties o the hostpolymer come rom surace plasmon resonance phenomenao nanoparticles dopant Te presence o silver nanoparticlesembedded inside the polymer has been con1047297rmed by thesurace plasmon resonance response which occurs at 983092983088983088ndash983092983090983088 nm or silver nanoparticles Te response transmittancere1047298ection optical bandgap dielectric constant optical con-ductivity dispersion reractive index and dielectric relax-ation time behavior o PVA-Ag nanoparticles 1047297lms at roomtemperature with varying concentration o silver nanoparti-cles at the same thickness o silver nanoparticles doped PVA1047297lms are also investigated

Tis paper is organized as ollows ollowing the intro-duction in Section 983089 experimental details are presented inSection 983090 Section 983091 is devoted to results and discussion andSection 983092 includes conclusion

2 Experimental Details

Nanoparticles (NPs) were prepared by ablation o a highpurity silver bulk in distilled water using the undamentalharmonic o a Nd YAG laser operating at983089983088983094983092 nm with pulsewidth o 983095 ns and 983089983088 Hz repetition rate Silver bulk was placedat the bottom o a water container with its surace at the ocalpoint o a 983096983088 mm convex lens Height o water on the silvertarget was 983089983090 mm Laser beam diameter was 983090 mm beore the

lens and has been calculated to be 983091983088m on the surace o thetarget Te volume o the water in the ablation container was983090983088 mL and silver target was ablated with 983093983088983088 laser pulses atdifferent energies Samples 983089ndash983091 were prepared with laser pulse

1047298uencies o 983089983093 983090 983091 Jcm2 respectively

By weighting the dried target beore and afer ablation

process the mass o ablated Ag nanoparticles were measuredto be 983091983095 times 983089983088minus4 983092 times 983089983088minus4 and 983094983093 times 983089983088minus4 g or S983089 S983090 and S983091respectively

PVA 1047297lms were prepared by dissolving 983089 g o PVA powderin 983090983088 mL distilled water at 983093983095∘C Mixture was stirred ortwo hours continuously to orm a viscous solution Te PVApowder was provided by Merck Co Germany Afer com-pleting desolation 983096 mL o silver nanoparticles suspensionwas added to the 983090983088 mL aqueous PVA solution and 1047297nallysamples was lef to dry on a plane surace or 983090983092 h at roomtemperature in close atmosphere to produce 983091 samples o 983088983089983092 mm thickness uniorm silver nanoparticles doped PVA1047297lms S983089 to S983091 are PVA 1047297lms which are doped with samples 983089

to 983091 nanoparticlesEM micrographs were taken using CM983089983090983088 system

orm PHILIPS Co Te X-ray diffraction (XRD) patterns o undoped and doped PVA 1047297lms was measured employingSOE-XRD diffract meter with Cu-K1038389 radiation (1103925 =1544060 A) Te Fourier transorm inrared spectroscopy was done with NEXUS 983096983095983088 F-IR Te transmission andre1047298ection spectrum o samples was recorded on a UV-Vis-NIR spectrophotometer rom Varian Cary-983093983088983088 Scan

3 Results and Discussion

Nanoparticle samples and PVA doped Ag nanoparticle 1047297lmsare shown in Figures 983089(a) and 983089(b) PVA is colorless polymerand with adding Ag nanoparticles its color is changed toyellow With increasing the concentration and decreasing thesize o doped nanoparticles color o 1047297lms has become darker

EM imageso nanoparticlesare presentedin Figure 983090 Inthis set o images the interbrain structure can be observedProduced nanoparticles are spherical without any aggrega-tion Te size distribution o nanoparticlescan be observed inFigure 983091 Tese graphs are plotted using the ldquomeasurementrdquosofware We have wide range o size distribution o nanopar-ticles in each sample but rom samples 983089 to 983091 we can see thatthe peak o size distribution o samples is tended to smaller

values In this case the size o Ag dopants in S983091 is minimum

while their concentration is maximum in comparison with S983089and S983090 In contrast the size o Ag dopants in S983089 is maximumbut their concentration is minimum When the spot size andpulse width o the laser pulse are constant increasing thelaser 1047298uence is due to increasing the laser pulse energy I the raction o the laser energy which is spent or ablationo nanoparticles assumed to be constant increasing the pulseenergy (photon numbers) leads to increasing the rate o ablation and increasing the pressure o the plasma plumewhich is ormed on the surace o the target during thelaser ablation process Te 1047297rst phenomenon will increasethe concentration o produced nanoparticles and the secondphenomenon leads to decreasing the size o nanoparticles

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Journal o Nanomaterials 983091

4 6 8 10 12 14 16 18 20 220

5

10

15

Size of Ag nanoparticles (nm)

S t a t i s t i c a

l d i s t r i b u t i o n

40nm

(a)

4 6 8 10 12 14 16 18 20 220

1

2

3

4

5

6

Size of Ag nanoparticles (nm)

S t a t i s t i c a l d i s t r i b u t i o n

40nm

(b)

4 6 8 10 12 14 16 18 20 220

5

10

15

Size of Ag nanoparticles (nm)

S t a t i s t i c a

l d i s t r i b u t i o n

40nm

(c)

F983145983143983157983154983141 983090 EM image and size distribution o Ag nanoparticle generated in distilled water with laser ablation method (a) S983089 (b) S983090 and (c)S983091

XRD spectrum o the Ag nanoparticles and pure PVApolymer 1047297lms and PVA doped Ag nanoparticles are shownin Figures 983091(a)ndash983091(c) Te diffraction pattern o undopedPVA indicates a diffraction bands at 2907317 = 1388∘ 983089983094983095983094∘983090983093983092∘ 983092983090983089983090∘ and 983092983096983096983096∘ It is well known that the peaks at2907317 lt 20∘ are due to crystalline nature o PVA polymermolecules which may be as a result o strong intermolecularand intramolecular hydrogen banding between the PVAchains [983095 983091983092] Te peaks at angles larger than 983090983088 ∘ may be due to impurities Te X-ray diffraction peaks o Agnanoparticles occur at 2907317 = 3815∘ 983092983092983091983097∘ 983094983092983095983092∘ 983095983095983093∘and 983096983089983094∘ corresponding to re1047298ections rom the ⟨111⟩ ⟨200⟩

⟨220⟩ ⟨311⟩ and ⟨222⟩ planes o Ag FCC lattice structurerespectively [983091983093 983091983094] All peaks observed in the sample o Ag nanoparticles have also been recreated in polymer 1047297lmsdoped with silver nanoparticles Te peaks o polymer X-ray diffraction pattern at 2907317 gt 20∘ have been removed aferdoping Te peak at 2907317 = 4212∘ in pure PVA is observed toshif up by about 983090983093∘ degree in PVA doped Ag nanoparticlesTis shif might be due to changes in the spacing valueso the corresponding planes Te intensity o diffracted X-ray photons rom 1047297lms has been increased noticeably afer thedoping process It may be due to two reasons For 2907317 lt 20∘increasing the peaks intensity is dueto increasing the number

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983092 Journal o Nanomaterials

10 20 30 40 50 60 70 80 90

0

500

1000

1500

2000

I n t e n s i t y

( a u )

Ag nanoparticles

PVA polymer

S1

2 (∘)

minus500

(a) S983089 (983089983093Jcm2)

10 20 30 40 50 60 70 80 90

0

500

1000

1500

2000

I n t e n s i t y

( a u )

Ag nanoparticles

PVA polymer

S2

2 (∘)

minus500

(b) S983090 (983090 Jcm2)

10 20 30 40 50 60 70 80 90

0

500

1000

1500

2000

I n t e n s i t y

( a u )

Ag nanoparticles

PVA polymer

S3

2 (∘)

minus500

(c) S983091 (983091 Jcm2)

F983145983143983157983154983141 983091 X-ray diffraction patterns o Ag nanoparticles PVA polymer and Ag nanoparticle doped PVA 1047297lms (a) S983089 (b) S983090 and (c) S983091

o PVA chains afer Ag doping Decreasing the intensity o peaks in FIR spectrum con1047297rms that afer doping numbero PVA chains are increased in the structure o the 1047297lmsSame results have been observed by Mahendia et al andGautam and Ram [983095 983091983092] For 2907317 gt 20∘ increasing theintensity o XRD peaks is due to increasing the number o crystallographic planes at certain angles

Te Fourier transorm inrared spectroscopy (FIR)

spectra o pure PVA and doped 1047297lms are shown in Figure 983092All spectra exhibit the characteristic absorption bands o purePVA which are 983091983093983096983088 983090983097983095983092 983089983095983092983088 983089983093983095983088 983089983092983094983088 and 983096983092983093 cmminus1

[983091983095 983091983096] It can be noticed that these treatments cause someobservable changes in the spectral eatures o the samples

in the range 983089983089983088983088ndash983093983088983088 cmminus1 (1047297ngerprint region) apart romnew absorption bands and slight changes in the intensitieso some absorption bands Te new bands may be correlatedlikewise with deects induced by the charge transer reactionbetween the polymer chain and the dopant Te vibrational

peaks at 983091983093983096983088 983090983097983095983092 983089983095983092983088 983089983092983094983088 and 983096983092983093 cmminus1 are assignedto OndashH stretching CndashH stretching C=O stretching CndashH

bend o CH2 and CH rocking o PVA respectively [983091983097983092983088] Further the vibrational peaks ound in the range 983089983089983091983088ndash

983094983093983088 cmminus1 may be attributed to AgndashO which indicate thatsilver nanoparticles doped in the PVA polymer matrix [983091983095]Te experimental data given in Figure 983092 indicate an increasein the vibrations o OndashH CndashH and C=O groups in the PVAmatrix afer adding Ag nanoparticles directly in the PVA1047297lm Such changes in OndashH CndashH and C=O vibrations have

been observed in other report [983092983088] Afer doping Ag somepolymers chains have been broken and some other chainshave been ormed instead Increasing the FIR spectrum in

the range o 983089983092983088983088 to 983089983094983088983088 cmminus1 corresponds to CndashH bondo CH2 and shows the broken chains Ag nanoparticles havegenerated new bonds in this range Decreasing the FIR

spectrum in the range o 983090983093983088983088 to 983091983095983088983088 cmminus1 shows theproduced polymerchains corresponds to OndashH stretching andCndashH stretching bonds

Te variation o transmittance () and re1047298ectance ()as a unction o wavelength or pure PVA polymer 1047297lmand samples 983089 to 983091 were recorded at room temperature and

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Journal o Nanomaterials 983093

500 1000 1500 2000 2500 3000 3500 40000

20

40

60

80

100

120

T

r a n s m i t t a n c e

Wavenumbers (cmminus1)

PVA

S1

S2

S3

F983145983143983157983154983141 983092 FIR spectrum o PVA pure 1047297lm and Ag nanoparticledoped in PVA polymer 1047297lms

200 400 600 800 1000 1200 1400 1600 1800 20000

01

02

03

04

05

06

07

0809

1

Wavelength (nm)

PVA

S1

S2

S3

Transmittance

Re1047298ectance

F983145983143983157983154983141 983093 Optical transmittance and re1047298ectance spectrum o sam-ples

are shown in Figure 983093 Pure PVA is a colorless polymerwithout any noticeable absorption in the visible range Tesharp increase observed in transmittance spectrum in therange o 983090983089983088 to 983090983092983096 nm is due to the presence o the PVApolymer bandgap [983089] Tis 1047297gure clearly indicates that aferadding nano-Ag in PVA polymer a valley at 983092983089983097 nm hasbeen created that its intensity continuously increasing withincreasing concentration o the dopant Tis new valley is

attributed to the ormation o charge transer complexes [983092983089]Te appearance o this valley in the visible region is dueto the surace plasmon resonance (SPR) nature o the Agnanoparticles embedded in PVA polymer dielectric medium

Aferdoping Ag nanoparticles in PVA polymer the re1047298ec-tion with increasing concentration o silver nanoparticlesdue to local 1047298uctuations charged particles declined

Te optical absorption coefficients o samples are evalu-ated rom the transmittance data using [983092983090]

1038389 = 1 ln 1048667

983131

(1 minus )22 + radic (1 minus )442 + 21048669

983133

(983089)

0 1 2 3 4 5 6 70

5

10

15

20

25

30

35

40

Photon energy (eV)

PVA

S1

S2

S3

A b s o r p t i o n

c o e

ffi c i e n t ( m m minus 1 )

F983145983143983157983154983141 983094 Optical absorption coefficient o 1047297lms

where and are the transmittance and re1047298ection respec-tively 1038389 is the absorption coefficient and is the thickness o the 1047297lms Figure 983094 presents the optical absorption coefficientsor undoped and nano-Ag doped PVA 1047297lms versus photonenergies Te absorption peak at 983090983097983093 eV or Ag nanoparticlesdoped in PVA polymer 1047297lms represents the characteristicsurace plasmon resonance dedicated to silver nanoparticlesTe presence o nanoparticles in the polymer 1047297lms could beconveniently ollowed by monitoringthe plasmon absorptionpeaks in the absorption spectrum Te larger absorptionpeak appeared in UV range is due to the energy gap o the PVA polymer which decreases owing to increasing theconcentration o Ag nanoparticles in the structure o the1047297lms Te position o the absorption edge was determinedby extrapolating the linear part o 1038389 versus ℎ] curves to zeroabsorption value [983092983089] Te band edge showed a decrease withincreasing concentration o Ag nanoparticles in PVA matrixTe absorption edge shifs towards higher wavelength indi-cating the decrease in the optical bandgap orthe doped 1047297lmsShifo the absorptionedgein the UVregionis due tochangesin the electron hole in the conduction and valence bands

Te most used method or estimation o the bandgapenergy rom optical measurement is the one proposed by auc and Grigorovici [983092983091] Te optical bandgap energy o samples was deduced rom the intercept o the extrapolated

linear part o the plot o (1038389)12 versus the photon energy with abscissa (Figure 983095) Tis ollows by the method o aucwhere

1038389 = 1048616 minus 10486171038389 (983090)

In this equation 1038389() is the absorption coefficient isthe photon energy is a actor that depends on transitionprobability and can be assumed to be constant within theoptical requency range and the index that is related tothe distribution o the density o states is an index whichassumes the values 983089983090 983091983090 983090 and 983091 depending on the natureo electronic transition aking = 2 which correspondsto indirectly allowed transition in pure PVA 1047297lm and nano-Ag doped PVA 1047297lms the bandgap energies o 1047297lms were

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983094 Journal o Nanomaterials

0 1 2 3 4 5 6 70

2

4

6

8

10

12

14

16

Photon energy (eV)

( 1038389 E ) 1 2

( m m minus 1 2 e V 1 2 )

PVA

S1

S2

S3

F983145983143983157983154983141 983095 (1038389)12 versus photon energy to illustrate auc method

calculated In an indirect gap a photon cannot be emittedbecause the electron must pass through an intermediatestate and transer momentum to the crystal lattice Teenergy gap o pure PVA sample is equal to 983092983097983094 eV andwith increasing the concentration o the Ag-nanoparticlesin the structure o 1047297lms bandgap energy is decreased Teextracted bandgap energy o sample are 983092983096983095 983092983096983092 and983092983095983096 eV or sample 983089ndash983091 respectively Te incorporation o the silver nanoparticles irrespective o their methodology o synthesis also affects the bandgap o the involved polymersystem Tis also con1047297rms the presence o the inorganic1047297llers inside the host [983089] Te variation o the calculated

values o optical bandgap re1047298ects the role o ormationo Ag-nanoparticles in modiying the electronic structureo the PVA matrix [983092983089 983092983092] Tese Ag-nanoparticles may be responsible or the ormation o localized electronicstates in the Highest Occupied Molecular Orbital-LowestUnoccupied Molecular Orbital (HOMO-LUMO) gap Teselocalized electronic states dominate the optical and electricalproperties vis-a-vis their role as trapping and recombinationcenters thus enhancing the low energy transitions leadingto the observed change in optical bandgap Te decrease inthe optical bandgap also re1047298ects the increase in the degreeo disorder in the 1047297lms which arises due to the change inpolymer structure [983092983092 983092983093]

Optical properties such as complex reractive index anddielectric constant or a certain range o wavelength betweenultraviolet and near inrared are important criteria or theselection o abricated 1047297lms or various applications Tereractive index is one o the undamental properties o a material because it is closely related to the electronicpolarizability o ions and the local 1047297eld inside the material [983096983097] Tus to urtherunderstand the interaction o Ag nanopar-ticles with PVA matrix optical properties such as complexreractive index and dielectric constant have been calculatedusing the undamental relations o photon transmittance ()re1047298ectance () and absorbance () Te complex reractiveindex is

= + that

is the real part and the extinction

0 1 2 3 4 5 6 713

14

15

16

17

18

19

2

Photon energy (eV)

R e f r a c t i v e i n d e x

PVA

S1

S2

S3

F983145983143983157983154983141 983096 Te reractive index o 1047297lms

coefficient

is the imaginary part Te reractive index

o

the 1047297lms was calculated using the ollowing equation [983092983094]

= 9830801 + 1 minus 983081 + radic 4(1 minus )2 minus 2 (983091)

in which = 110392510383894 Figures 983096 and 983097 show the photonenergy dependence o reractive index and the extinctioncoefficient or pure PVA and nano-Ag doped PVA 1047297lms Itcan be discerned rom Figure 983096 that the reractive index o nano-Ag doped PVA 1047297lms is lower than the reractive indexo pure PVA and it decreases with increasing concentrationo Ag nanoparticles in PVA matrix Tis property is inherentin all conductors and due to localized 1047298uctuation o charged

particles in medium Also decreasing the value o reractiveindex may be an indication o low density o 1047297lms whichleads to increasing the interatomic spacing [983092983093]Tisisduetoormation o intermolecular hydrogen bonding between Ag-nanoparticles and the adjacent OH groups Te dependenceo the reractive index on the 1047297lm density can be discussed by the well-known Clausius-Mossotti relation [983092983094]

Te extinction coefficient describes the properties o the material with respect to light o a given wavelength andindicates the absorption changes when the electromagneticwavepropagates through the material In Figure 983097 the extinc-tion coefficient o the doped samples have a peak at =295 eV which increases with increasing concentration o Ag nanoparticles in PVA dielectric medium Te extinctioncoefficient increases due to surace plasmon absorption indoped samples while the reractive index decreases in thisregion Tere is anomalous dispersion regions when 225 lt lt 2983097983093 eV and gt 485 eV as well as normal dispersionwhen 295 lt lt 345 eV or doped samples

Te complex dielectric unction is = 1103925 + 907317 where1103925 is the real part and 907317 is the imaginary part o dielectricconstant Te real and imaginary parts o dielectric constantare expressed as

1103925 = 2 minus 2907317 = 2 (983092)

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Journal o Nanomaterials 983095

0 1 2 3 4 5 6 70

1

2

3

4

5

6

7

8

Photon energy (eV)

E x t i n c t i o

n c o e

ffi c i e n t

PVA

S1

S2

S3

times10minus4

F983145983143983157983154983141 983097 Te extinction coefficient spectrum o 1047297lms

0 1 2 3 4 5 6 715

2

25

3

35

4

Photon energy (eV)

PVA

S1

S2

S3

1103925 r

F983145983143983157983154983141 983089983088 Real part o the dielectric constant o pure PVA and Agnanoparticle doped 1047297lms

Te real part o dielectric constant is related to the disper-sion In order to explain the dispersion it is necessary to takeinto account the actual motion o the electrons in the opticalmedium through which the light is traveling Te imaginary part represents the dissipative rate o electromagnetic wavepropagation in the medium Te real and imaginary partsdependences on photon energy o samples are shown in

Figures 983089983088 and 983089983089 respectively It can be concluded that 1103925is larger than 907317 because it mainly depends on 2 Withincreasing the amount o silver nanoparticles in PVA the realpart o dielectric constant is decreased It is due to decreaseo the dielectric property o 1047297lms because o Ag nanoparticlesmetal lattice in the host PVA polymer matrix Te normaldispersion is associated with an increase in Re() with andanomalous dispersion is associated with the reverse mecha-nism Normal dispersion is occurred everywhere expect inthe neighborhood o the resonance requency In this regionthe anomalous dispersion is appreciable Since a positiveimaginary part to 907317 represents dissipation o energy rom theelectromagnetic wave into the medium the regions where

907317

0 1 2 3 4 5 6 70

05

1

15

2

25

Photon energy (eV)

PVA

S1

S2

S3

times10minus3

1103925 i

F983145983143983157983154983141 983089983089 Imaginary part o the dielectric unction o 1047297lms

is large are called regions o resonant absorption [983092983095] Tepeak that appears in Figure 983089983089 at = 295 eV shows theplasmonic absorption

Te complex dielectric unction and complex opticalconductivity are introduced through Maxwellrsquos equationsTe interband transitions have threshold energy at the energy gap Tat is we expect the requency dependence o thereal part o the conductivity 1103925() due to an interbandtransition to exhibit a threshold or an allowed electronictransition [983092983096] In interband transition real 1103925 and imaginary 907317 components o optical conductivity are described as [983092983096ndash983093983088]

1103925 = 9073170907317 = 11039250 (983093)

where is the angular requency o electromagnetic wave and0 is the ree space dielectric constant Te real and imaginary parts o the optical conductivity dependence on the photonenergy are shown in Figures 983089983090 and 983089983091 respectively

Te real optical conductivity in bandgap energy regionafer doping the Ag-nanoparticles in PVA polymer decreasesIt can be due to the segregation effect [983092983089 983093983089] Te segregatedeffect is the dispersion o metallic particles restricted by thepresence o much larger polymeric particles Te observedeffect o Ag nanoparticles on the optical conductivity and

conduction behavior o PVA 1047297lms can be explained on thebasis o charge transer complex ormation involving PVAmolecules and the dopant When PVA polymer is mixedwith Ag nanoparticles as a result the 1047297ller is pushed intointerstitial space between the polymer particles and ormsa segregated network [983093983089] At higher dopant concentrationthere may be segregation o the dopant in the polymermatrix which decreases the conductivity Tus motion o charge carriers or localized 1047298uctuations o charged parti-cles in molecular aggregates impedes optical conductivityMoreover there is a weak peak at = 295 eV that can beseen only in the doped samples Tis new peak is attributedto the ormation o charge transer or the surace plasmon

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983096 Journal o Nanomaterials

0 1 2 3 4 5 6 70

02

04

06

08

1

12

14

16

18

2

Energy photon (eV)

PVA

S1

S2

S3

times10minus16

907317 r

( S m )

F983145983143983157983154983141 983089983090 Real part o the optical conductivity o pure PVA anddoped 1047297lms

0 1 2 3 4 5 6 70

05

1

15

2

25

3

35

Energy photon (eV)

PVA

S1

S2

S3

times10minus13

907317 i

( S m )

F983145983143983157983154983141 983089983091 Imaginary part o the optical conductivity o pure PVAand doped 1047297lms

silver nanoparticles Another result is that by increasingthe concentration o Ag nanoparticles in PVA matrix theimaginary part o optical conductivity decreases

A dielectric sample in an external electric 1047297eld acquiresa nonzero macroscopic dipole moment indicating that thedielectric is polarized under the in1047298uence o the 1047297eld Polar-ization o dielectric material achieves its equilibrium valuenot instantaneously but rather over a period o time [983093983090]Te dielectric relaxation time can be evaluated using

= infin minus 1103925907317 (983094)

Figure 983089983092 shows the dielectric relaxation time as a unc-tion o photon energy or pure PVA polymer and Agnanoparticle doped PVA 1047297lms Te valley at 983090983097983093 eV ordoped samples increases with increasing the concentrationo Ag nanoparticles in the structure o the 1047297lms In otherwords the relaxation time o dipole orientation decreases

2 25 3 35 4 45 5 550

02

04

06

08

1

12

14

16

18

2

Photon energy (eV)

R e

l a x a t

i o n t i m e

( s )

PVA

S1

S2

S3

times10minus12

F983145983143983157983154983141 983089983092 Relaxation time versus photon energy o 1047297lms

Tis is another reason or decreasing the dielectric unctionand increasing the conductivity o 1047297lms with increasing theconcentration o nanoparticles in their structure [983093983091]

Reractive index dispersion is a determinant actor inoptical materials It is a signi1047297cant actor in opticalcommuni-cation andin designingdevices orspectral dispersion[983091983093]Inthe normal dispersion region the reractive index dispersionhasbeen analyzed using thesingleoscillator model developedby theory o Wemple and DiDomenico [983093983092] Tey intro-duced a dispersion-energy parameter which connectsthe coordination number and the charge distribution withineach unit cell

is closely related to chemical bonding

Also they de1047297ned a single oscillator parameter 0 whichis proportional to the energy o oscillator In terms o thisdispersion energy and single oscillator energy 0 thereractive index at requency can be written as

12 minus 1 = 0

minus 10

(ℎ])2 (983095)

Te values o and 0 can be obtained rom the

intercept and slope o the linear part o (2 minus 1)minus1 plot versus

(ℎ]

)2 as is shown in Figure 983089983093 Also dispersion o reractive

index is controlled by the combined effects o and 0 Tecalculated values o the dispersion parameters (0 and )as well as the corresponding optical constant ( = 2) orthe pure PVA 1047297lm and samples 983089 to 983091 are listed in able 983089Te dispersion energy values decreases with increasing theconcentration o Ag nanoparticles in PVA 1047297lms because theanion strength o the dielectric medium has been declinedTereore the PVA polymer host is less willing to keep theelectrons in their outer layers Te single oscillator energy isan average energy gap as pointed out in many reerences [983093983088]Te 0 value o the 1047297lms is related empirically to the lowestindirect bandgap by 0 asymp 103 Tis relation is in goodagreement with the single oscillator model

7272019 pva films

httpslidepdfcomreaderfullpva-films 911

Journal o Nanomaterials 983097

10 105 11 115 12 125 1302

04

06

08

1

12

14

16

PVA

S1

S2

S3

(

n 2

minus

1 ) minus 1

E2 (eV2)

F983145983143983157983154983141 983089983093Plot o (2minus1) versus squared photon energy o pure PVAand doping samples

983137983138983148983141 983089 Dispersion parameters o 1047297lmsSamples 0

PVA 983089983093983094 983090983092983092 983093983089983097 983095983092983097

S983089 983089983092983096 983090983089983097 983093983088983092 983094983088983091

S983090 983089983091983095 983089983096983097 983092983097983095 983092983092983094

S983091 983089983089983097 983089983092983090 983092983096983095 983090983088983093

4 Conclusions

Preparation o silver nanoparticles by laser ablation methodat different 1047298uencies o laser pulse in pure water is investi-gated Te EM analysis revealed that generated nanoparti-

cles in this experimental condition are almost spherical andtheir average size was 983094ndash983089983090 nm and with increasing the laserpulse 1047298uence the size o nanoparticles is decreased Te X-ray diffraction spectrum reveals that the number o crystal-lographic planes at certain angles is increased afer doping Agnanoparticles in the structure o PVA FIR spectrum peakscorrespond to molecular vibrations and chemical bondsindicate the presence o silver in the PVA polymer structureTe optical bandgap energy o the samples is decreasedwith increasing the concentrations o silver nanoparticlesReractive index and dielectric constant are decreased withincreasing the concentration o Ag nanoparticles Increaseo dopant concentration resulted in a decrease in real part

o the optical conductivity because o segregation effectTe reractive index and consequently the related dispersionparameters o PVA and doped PVA have been determinedand explained using the Wemple-DiDomenico model

References

[983089] A Nimrodh Ananth and S Umapathy ldquoOn the optical andthermal properties o in situex situ reduced Ag NPrsquosPVAcomposites and its role as a simple SPR-based protein sensorrdquo Applied Nanoscience vol 983089 no 983090 pp 983096983095ndash983097983094 983090983088983089983089

[983090] G Nesher G Marom and D Avnir ldquoMetal-polymer compos-ites synthesis and characterization o polyaniline and other

polymer at Silver compositionsrdquo Chemistry of Materialsvol983090983088no 983089983091 pp 983092983092983090983093ndash983092983092983091983090 983090983088983088983096

[983091] P-H Wang Y-Z Wu andQ-R ZhuldquoPolymermetal compositeparticles polymer core and metal shellrdquo Journal of MaterialsScience Letters vol 983090983089 no 983090983091 pp 983089983096983090983093ndash983089983096983090983096 983090983088983088983090

[983092] S Clemenson P Alcouffe L David and E Espuche ldquoStructureand morphology o membranes prepared rom polyvinyl alco-hol and silver nitrate in1047298uence o the annealing treatment ando the 1047297lm thicknessrdquo Desalination vol 983090983088983088 no 983089-983091 pp 983092983091983095ndash983092983091983097 983090983088983088983094

[983093] K Akamatsu S akei M Mizuhata et al ldquoPreparation andcharacterization o polymer thin 1047297lms containing silver andsilver sul1047297de nanoparticlesrdquo Tin Solid Films vol 983091983093983097 no 983089 pp983093983093ndash983094983088 983090983088983088983088

[983094] R Zeng M Z Rong M Q Zhang H C Liang and H MZeng ldquoLaser ablation o polymer-based silver nanocompositesrdquo Applied Surface Science vol 983089983096983095 no 983091-983092 pp 983090983091983097ndash983090983092983095 983090983088983088983090

[983095] S Mahendia A K omar and S Kumar ldquoElectrical conduc-tivity and dielectric spectroscopic studies o PVA-Ag nanocom-posite 1047297lmsrdquo Journal of Alloys and Compounds vol 983093983088983096 no 983090pp 983092983088983094ndash983092983089983089 983090983088983089983088

[983096] N Singh and P K Khanna ldquoIn situ synthesis o silver nano-particles in polymethylmethacrylaterdquo Materials Chemistry and Physics vol 983089983088983092 no 983090-983091 pp 983091983094983095ndash983091983095983090 983090983088983088983095

[983097] P K Khanna R Gokhale V V V S Subbarao A K Vish-wanath B K Das and C V V Satyanarayana ldquoPVA stabilizedgold nanoparticles by use o unexplored albeit conventionalreducing agentrdquo Materials Chemistry and Physics vol 983097983090 no983089 pp 983090983090983097ndash983090983091983091 983090983088983088983093

[983089983088] K Akamatsu S akei M Mizuhata et al ldquoPreparation andcharacterization o polymer thin 1047297lms containing silver andsilver sul1047297de nanoparticlesrdquo Tin Solid Films vol 983091983093983097 no 983089 pp983093983093ndash983094983088 983090983088983088983088

[983089983089] I Hussain M Brust A J Papworth and A I Cooper

ldquoPreparationo acrylate-stabilized goldand silver hydrosols andgold-polymer composite 1047297lmsrdquo Langmuir vol 983089983097 no 983089983089 pp983092983096983091983089ndash983092983096983091983093 983090983088983088983091

[983089983090] S A Zavyalov A N Pivkina and J Schoonman ldquoFormationand characterization o metal-polymer nanostructured com-positesrdquo Solid State Ionics vol 983089983092983095 no 983091-983092 pp 983092983089983093ndash983092983089983097 983090983088983088983090

[983089983091] J Lee D Bhattacharyya A J Easteal and J B Metson ldquoProp-erties o nano-ZnOpoly(vinyl alcohol)poly(ethylene oxide)composite thin 1047297lmsrdquo Current Applied Physics vol 983096 no 983089 pp983092983090ndash983092983095 983090983088983088983096

[983089983092] Z Zhong D Wang Y Cui M W Bockrath and C H LieberldquoNanowire crossbar arrays as address decoders or integratednanosystemsrdquo Science vol 983091983088983090 no 983093983094983092983097 pp 983089983091983095983095ndash983089983091983095983097 983090983088983088983091

[983089983093] D S Hopkins D Pekker P M Goldbart and A Bezryadin

ldquoQuantum intererence device made by DNA templating o superconducting nanowiresrdquo Science vol 983091983088983096 no 983093983095983090983097 pp983089983095983094983090ndash983089983095983094983093 983090983088983088983093

[983089983094] S Clemenson D Leonard D Sage L David and E EspucheldquoMetal nanocomposite 1047297lms prepared in Situ rom PVA andsilver nitrate Study o the nanostructuration process andmorphology as a unction o the in Situ routesrdquo Journal of Polymer Science A vol 983092983094 no 983094 pp 983090983088983094983090ndash983090983088983095983089 983090983088983088983096

[983089983095] M K emgire and S S Joshi ldquoOptical and structural studies o silver nanoparticlesrdquo Radiation Physics and Chemistry vol 983095983089no 983093 pp 983089983088983091983097ndash983089983088983092983092 983090983088983088983092

[983089983096] M Zheng M Gu Y Jin and G Jin ldquoOptical properties o silver-dispersed PVP thin 1047297lmrdquo Materials Research Bulletin vol 983091983094no 983093-983094 pp 983096983093983091ndash983096983093983097 983090983088983088983089

7272019 pva films

httpslidepdfcomreaderfullpva-films 1011

983089983088 Journal o Nanomaterials

[983089983097] O L A Monti J Fourkas and D J Nesbitt ldquoDiffraction-limited photogeneration and characterization o silver nanopar-ticlesrdquo Journal of Physical Chemistry B vol 983089983088983096 no 983093 pp 983089983094983088983092ndash983089983094983089983090 983090983088983088983092

[983090983088] K L Kelly E Coronado L L Zhao and G C Schatz ldquoTeopti-cal properties o metal nanoparticles the in1047298uence o sizeshape and dielectric environmentrdquo Journal of Physical Che-

mistry B vol 983089983088983095 no 983091 pp 983094983094983096ndash983094983095983095 983090983088983088983091

[983090983089] H Weickmann J C iller R Tomann and R MulhauptldquoMetallized organoclays as new intermediates or aqueous nan-ohybrid dispersions nanohybrid catalysts and antimicrobialpolymer hybrid nanocompositesrdquo Macromolecular Materialsand Engineering vol 983090983097983088 no 983097 pp 983096983095983093ndash983096983096983091 983090983088983088983093

[983090983090] U Keirbeg and M Vollmer Optical Properties of Metal Clusters vol 983090983093 o Springer Series in Material Science 983089983097983097983093

[983090983091] S Chen and J M Sommers ldquoAlkanethiolate-protected coppernanoparticles spectroscopy electrochemistry and solid-statemorphological evolutionrdquo Journal of Physical Chemistry B vol983089983088983093 no 983091983095 pp 983096983096983089983094ndash983096983096983090983088 983090983088983088983089

[983090983092] A A Scalisi G Compagnini L DrsquoUrso and O Puglisi ldquoNon-linearopticalactivity in Ag-SiO

2 nanocomposite thin 1047297lms with

different silver concentrationrdquo Applied Surface Science vol 983090983090983094no 983089ndash983091 pp 983090983091983095ndash983090983092983089 983090983088983088983092

[983090983093] G Yang W Wang Y Zhou H Lu G Yang and Z Chen ldquoLin-ear and nonlinear optical properties o Ag nanoclusterBaiO3

composite 1047297lmsrdquo Applied Physics Letters vol 983096983089 no 983090983089 pp983091983097983094983097ndash983091983097983095983089 983090983088983088983090

[983090983094] H B Liao R F Xiao H Wang K S Wong and G K L WongldquoLarge third-order optical nonlinearity in AuiO2 composite1047297lms measured on a emtosecond time scalerdquo Applied PhysicsLetters vol 983095983090 no 983089983093 pp 983089983096983089983095ndash983089983096983089983097 983089983097983097983096

[983090983095] A K Sarychev D J Bergman and Y Yagil ldquoTeory o theoptical and microwave properties o metal-dielectric 1047297lmsrdquoPhysical Review B vol 983093983089 no 983096 pp 983093983091983094983094ndash983093983091983096983093 983089983097983097983093

[983090983096] G Mie ldquoBeitrage zur Optik truber Medien speziell kolloidalerMetallosungenrdquo Annalen der Physik vol 983091983091983088 pp 983091983095983095ndash983092983092983093 983089983097983088983096

[983090983097] R Gans ldquoUber die Form ultramikroskopischer Silberteilchenrdquo Annalen der Physik vol 983091983093983090 no 983089983088 pp 983090983095983088ndash983090983096983092 983089983097983089983093

[983091983088] S Link and M A El-Sayed ldquoSpectral properties and relaxationdynamics o surace plasmon electronic oscillations in gold andsilver nanodots and nanorodsrdquo Journal of Physical Chemistry B vol 983089983088983091 no 983092983088 pp 983096983092983089983088ndash983096983092983090983094 983089983097983097983097

[983091983089] G Fussell J Tomas J Scanlon A Lowman and M Mar-colongo ldquoTe effect o protein-ree versus protein-containingmedium on the mechanical properties and uptake o ions o PVAPVP hydrogelsrdquo Journalof BiomaterialsScience vol983089983094 no983092 pp 983092983096983097ndash983093983088983091 983090983088983088983093

[983091983090] suji Mizuki S Ozono and M suji ldquoLaser-induced sil-

ver nanocrystal ormation in polyvinylpyrrolidone solutionsrdquo Journal of Photochemistry and Photobiology A vol 983090983088983094 no 983090-983091pp 983089983091983092ndash983089983091983097 983090983088983088983097

[983091983091] J-P Sylvestre S Poulin A V Kabashin E Sacher M Meunierand J H Luong ldquoSurace chemistry o gold nanoparticlesproduced by laser ablation in aqueous mediardquo Journal of Physical Chemistry B vol 983089983088983096 no 983092983091 pp 983089983094983096983094983092ndash983089983094983096983094983097 983090983088983088983092

[983091983092] A Gautam and S Ram ldquoPreparation and thermomechanicalproperties o Ag-PVA nanocomposite 1047297lmsrdquo Materials Chem-istry and Physics vol 983089983089983097 no 983089-983090 pp 983090983094983094ndash983090983095983089 983090983088983089983088

[983091983093] I Saini J Rozra N Chandak S Aggarwal P K Sharmaand A Sharma ldquoailoring o electrical optical and structuralproperties o PVA by addition o Ag nanoparticlesrdquo MaterChem Phys vol 983089983091983097 pp 983096983088983090ndash983096983089983088 983090983088983089983091

[983091983094] S Mahendia A K omar and S Kumar ldquoNano-Ag dopinginduced changes in optical and electrical behaviour o PVA1047297lmsrdquo Materials Science and Engineering B vol 983089983095983094 no 983095 pp983093983091983088ndash983093983091983092 983090983088983089983089

[983091983095] M Abdelaziz and E M Abdelrazek ldquoEffect o dopant mixtureon structural optical and electron spin resonance properties o polyvinyl alcoholrdquo Physica B vol 983091983097983088 no 983089-983090 pp 983089ndash983097 983090983088983088983095

[983091983096] B Suo X Su J Wu D Chen A Wang and Z Guo ldquoPoly (vinyl alcohol) thin 1047297lm 1047297lled with CdSe-ZnS quantum dotsabrication characterization and optical propertiesrdquo MaterialsChemistry and Physics vol 983089983089983097 no 983089-983090 pp 983090983091983095ndash983090983092983090 983090983088983089983088

[983091983097] B Karthikeyan ldquoSpectroscopic studies on Ag-polyvinyl alcoholnanocomposite 1047297lmsrdquo Physica B vol 983091983094983092 no 983089ndash983092 pp 983091983090983096ndash983091983091983090983090983088983088983093

[983092983088] A S Kutsenko and V M Granchak ldquoPhotochemical synthesiso silver nanoparticles in polyvinyl alcohol matricesrdquo Teoreti-cal and Experimental Chemistry vol 983092983093no 983093 pp 983091983089983091ndash983091983089983096983090983088983088983097

[983092983089] C U Devi A K Sharma and V V R N Rao ldquoElectrical andoptical properties o pure and silver nitrate-doped polyvinylalcohol 1047297lmsrdquo Materials Letters vol 983093983094 no 983091 pp 983089983094983095ndash983089983095983092 983090983088983088983090

[983092983090] B G Streetman Solid State Electronic Devices Prentice HallNew Jersey NJ USA 983091rd edition 983089983097983097983088

[983092983091] J auc and R Grigorovici ldquoOptical properties and electronicstructure o amorphous germaniumrdquo Physica Status Solidi (B) vol 983089983093 no 983090 pp 983094983090983095ndash983094983091983095 983089983097983094983094

[983092983092] J Rozra I Saini A Sharma et al ldquoCu nanoparticles inducedstructural optical and electrical modi1047297cation in PVArdquo Materi-als Chemistry and Physics vol 983089983091983092 no 983090-983091 pp 983089983089983090983089ndash983089983089983090983094 983090983088983089983090

[983092983093] M Abdelaziz ldquoCerium (III) doping effects on optical andthermal properties o PVA 1047297lmsrdquo Physica B vol 983092983088983094 no 983094-983095pp 983089983091983088983088ndash983089983091983088983095 983090983088983089983089

[983092983094] C Kittle Introduction to Solid State Physics vol 983092983088983093 John Wiley amp Sons New York NY USA 983089983097983095983089

[983092983095] J D Jackson Classical Electrodynamics John Wiley amp Sons 983091rdedition 983089983097983097983097

[983092983096] M S Dresselhaus Solid State Physics Part II Optical Propertiesof Solids vol 983094 983090983088983088983089

[983092983097] J N Hodgson Optical Absorption and Dispersion in Solids Chapman amp Hall London UK 983089983097983095983089

[983093983088] Y Caglar S Ilican and M Caglar ldquoSingle-oscillator modeland determination o optical constants o spray pyrolyzedamorphous SnO2 thin 1047297lmsrdquo European Physical Journal B vol983093983096 no 983091 pp 983090983093983089ndash983090983093983094 983090983088983088983095

[983093983089] Y Seok Kim Electrical Conductivity of Segregated NetworkPolymer Nanoposites vol 983089983091983095 983090983088983088983095

[983093983090] Y Feldman A Puzenko and Y Ryabov ldquoDielectric relaxationphenomena in complex materialsrdquo in Advances in Chemical

Physics vol 983089983091983091 pp 983089ndash983089983090983093 Department o Applied Physics TeHebrew University o Jerusalem Jerusalem Israel 983090983088983088983094

[983093983091] S Mahendia A K omar R P Chahal P Goyal and S KumarldquoOptical and structural properties o poly(vinyl alcohol) 1047297lmsembedded with citrate-stabilized gold nanoparticlesrdquo Journal of Physics D vol 983092983092 no 983090983088 Article ID 983090983088983093983089983088983093 983090983088983089983089

[983093983092] S H Wemple and M DiDomenico ldquoBehavior o the electronicdielectric constant in covalent and ionic materialsrdquo Physical Review B vol 983091 no 983092 pp 983089983091983091983096ndash983089983091983093983089 983089983097983095983089

7272019 pva films

httpslidepdfcomreaderfullpva-films 1111

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2013Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The ScientifcWorld Journal

Impact Factor 1730

28 Days Fast Track Peer Review

All Subject Areas of Science

Submit at httpwwwtswjcom

7272019 pva films

httpslidepdfcomreaderfullpva-films 211

983090 Journal o Nanomaterials

(a)

Pure PVA S1 S3S2

(b)

F983145983143983157983154983141 983089 (a) Ag nanoparticle samples in distilledwater and(b) purePVA polymer 1047297lm and Ag doped PVA 1047297lms

by laser ablation method Te laser ablation technique in aliquid produces proper metal nanoparticle samples to acili-tate investigation o their photophysical and photochemicalproperties [983091983090] A remarkable and advantageous eatureo nanoparticles prepared using this technique in contrastto those prepared using chemical synthesis is absence o uncontrolled byproducts [983091983090 983091983091] Interesting effects wereobserved on crystal structure and its optical properties Tenoticeable main variations o optical properties o the hostpolymer come rom surace plasmon resonance phenomenao nanoparticles dopant Te presence o silver nanoparticlesembedded inside the polymer has been con1047297rmed by thesurace plasmon resonance response which occurs at 983092983088983088ndash983092983090983088 nm or silver nanoparticles Te response transmittancere1047298ection optical bandgap dielectric constant optical con-ductivity dispersion reractive index and dielectric relax-ation time behavior o PVA-Ag nanoparticles 1047297lms at roomtemperature with varying concentration o silver nanoparti-cles at the same thickness o silver nanoparticles doped PVA1047297lms are also investigated

Tis paper is organized as ollows ollowing the intro-duction in Section 983089 experimental details are presented inSection 983090 Section 983091 is devoted to results and discussion andSection 983092 includes conclusion

2 Experimental Details

Nanoparticles (NPs) were prepared by ablation o a highpurity silver bulk in distilled water using the undamentalharmonic o a Nd YAG laser operating at983089983088983094983092 nm with pulsewidth o 983095 ns and 983089983088 Hz repetition rate Silver bulk was placedat the bottom o a water container with its surace at the ocalpoint o a 983096983088 mm convex lens Height o water on the silvertarget was 983089983090 mm Laser beam diameter was 983090 mm beore the

lens and has been calculated to be 983091983088m on the surace o thetarget Te volume o the water in the ablation container was983090983088 mL and silver target was ablated with 983093983088983088 laser pulses atdifferent energies Samples 983089ndash983091 were prepared with laser pulse

1047298uencies o 983089983093 983090 983091 Jcm2 respectively

By weighting the dried target beore and afer ablation

process the mass o ablated Ag nanoparticles were measuredto be 983091983095 times 983089983088minus4 983092 times 983089983088minus4 and 983094983093 times 983089983088minus4 g or S983089 S983090 and S983091respectively

PVA 1047297lms were prepared by dissolving 983089 g o PVA powderin 983090983088 mL distilled water at 983093983095∘C Mixture was stirred ortwo hours continuously to orm a viscous solution Te PVApowder was provided by Merck Co Germany Afer com-pleting desolation 983096 mL o silver nanoparticles suspensionwas added to the 983090983088 mL aqueous PVA solution and 1047297nallysamples was lef to dry on a plane surace or 983090983092 h at roomtemperature in close atmosphere to produce 983091 samples o 983088983089983092 mm thickness uniorm silver nanoparticles doped PVA1047297lms S983089 to S983091 are PVA 1047297lms which are doped with samples 983089

to 983091 nanoparticlesEM micrographs were taken using CM983089983090983088 system

orm PHILIPS Co Te X-ray diffraction (XRD) patterns o undoped and doped PVA 1047297lms was measured employingSOE-XRD diffract meter with Cu-K1038389 radiation (1103925 =1544060 A) Te Fourier transorm inrared spectroscopy was done with NEXUS 983096983095983088 F-IR Te transmission andre1047298ection spectrum o samples was recorded on a UV-Vis-NIR spectrophotometer rom Varian Cary-983093983088983088 Scan

3 Results and Discussion

Nanoparticle samples and PVA doped Ag nanoparticle 1047297lmsare shown in Figures 983089(a) and 983089(b) PVA is colorless polymerand with adding Ag nanoparticles its color is changed toyellow With increasing the concentration and decreasing thesize o doped nanoparticles color o 1047297lms has become darker

EM imageso nanoparticlesare presentedin Figure 983090 Inthis set o images the interbrain structure can be observedProduced nanoparticles are spherical without any aggrega-tion Te size distribution o nanoparticlescan be observed inFigure 983091 Tese graphs are plotted using the ldquomeasurementrdquosofware We have wide range o size distribution o nanopar-ticles in each sample but rom samples 983089 to 983091 we can see thatthe peak o size distribution o samples is tended to smaller

values In this case the size o Ag dopants in S983091 is minimum

while their concentration is maximum in comparison with S983089and S983090 In contrast the size o Ag dopants in S983089 is maximumbut their concentration is minimum When the spot size andpulse width o the laser pulse are constant increasing thelaser 1047298uence is due to increasing the laser pulse energy I the raction o the laser energy which is spent or ablationo nanoparticles assumed to be constant increasing the pulseenergy (photon numbers) leads to increasing the rate o ablation and increasing the pressure o the plasma plumewhich is ormed on the surace o the target during thelaser ablation process Te 1047297rst phenomenon will increasethe concentration o produced nanoparticles and the secondphenomenon leads to decreasing the size o nanoparticles

7272019 pva films

httpslidepdfcomreaderfullpva-films 311

Journal o Nanomaterials 983091

4 6 8 10 12 14 16 18 20 220

5

10

15

Size of Ag nanoparticles (nm)

S t a t i s t i c a

l d i s t r i b u t i o n

40nm

(a)

4 6 8 10 12 14 16 18 20 220

1

2

3

4

5

6

Size of Ag nanoparticles (nm)

S t a t i s t i c a l d i s t r i b u t i o n

40nm

(b)

4 6 8 10 12 14 16 18 20 220

5

10

15

Size of Ag nanoparticles (nm)

S t a t i s t i c a

l d i s t r i b u t i o n

40nm

(c)

F983145983143983157983154983141 983090 EM image and size distribution o Ag nanoparticle generated in distilled water with laser ablation method (a) S983089 (b) S983090 and (c)S983091

XRD spectrum o the Ag nanoparticles and pure PVApolymer 1047297lms and PVA doped Ag nanoparticles are shownin Figures 983091(a)ndash983091(c) Te diffraction pattern o undopedPVA indicates a diffraction bands at 2907317 = 1388∘ 983089983094983095983094∘983090983093983092∘ 983092983090983089983090∘ and 983092983096983096983096∘ It is well known that the peaks at2907317 lt 20∘ are due to crystalline nature o PVA polymermolecules which may be as a result o strong intermolecularand intramolecular hydrogen banding between the PVAchains [983095 983091983092] Te peaks at angles larger than 983090983088 ∘ may be due to impurities Te X-ray diffraction peaks o Agnanoparticles occur at 2907317 = 3815∘ 983092983092983091983097∘ 983094983092983095983092∘ 983095983095983093∘and 983096983089983094∘ corresponding to re1047298ections rom the ⟨111⟩ ⟨200⟩

⟨220⟩ ⟨311⟩ and ⟨222⟩ planes o Ag FCC lattice structurerespectively [983091983093 983091983094] All peaks observed in the sample o Ag nanoparticles have also been recreated in polymer 1047297lmsdoped with silver nanoparticles Te peaks o polymer X-ray diffraction pattern at 2907317 gt 20∘ have been removed aferdoping Te peak at 2907317 = 4212∘ in pure PVA is observed toshif up by about 983090983093∘ degree in PVA doped Ag nanoparticlesTis shif might be due to changes in the spacing valueso the corresponding planes Te intensity o diffracted X-ray photons rom 1047297lms has been increased noticeably afer thedoping process It may be due to two reasons For 2907317 lt 20∘increasing the peaks intensity is dueto increasing the number

7272019 pva films

httpslidepdfcomreaderfullpva-films 411

983092 Journal o Nanomaterials

10 20 30 40 50 60 70 80 90

0

500

1000

1500

2000

I n t e n s i t y

( a u )

Ag nanoparticles

PVA polymer

S1

2 (∘)

minus500

(a) S983089 (983089983093Jcm2)

10 20 30 40 50 60 70 80 90

0

500

1000

1500

2000

I n t e n s i t y

( a u )

Ag nanoparticles

PVA polymer

S2

2 (∘)

minus500

(b) S983090 (983090 Jcm2)

10 20 30 40 50 60 70 80 90

0

500

1000

1500

2000

I n t e n s i t y

( a u )

Ag nanoparticles

PVA polymer

S3

2 (∘)

minus500

(c) S983091 (983091 Jcm2)

F983145983143983157983154983141 983091 X-ray diffraction patterns o Ag nanoparticles PVA polymer and Ag nanoparticle doped PVA 1047297lms (a) S983089 (b) S983090 and (c) S983091

o PVA chains afer Ag doping Decreasing the intensity o peaks in FIR spectrum con1047297rms that afer doping numbero PVA chains are increased in the structure o the 1047297lmsSame results have been observed by Mahendia et al andGautam and Ram [983095 983091983092] For 2907317 gt 20∘ increasing theintensity o XRD peaks is due to increasing the number o crystallographic planes at certain angles

Te Fourier transorm inrared spectroscopy (FIR)

spectra o pure PVA and doped 1047297lms are shown in Figure 983092All spectra exhibit the characteristic absorption bands o purePVA which are 983091983093983096983088 983090983097983095983092 983089983095983092983088 983089983093983095983088 983089983092983094983088 and 983096983092983093 cmminus1

[983091983095 983091983096] It can be noticed that these treatments cause someobservable changes in the spectral eatures o the samples

in the range 983089983089983088983088ndash983093983088983088 cmminus1 (1047297ngerprint region) apart romnew absorption bands and slight changes in the intensitieso some absorption bands Te new bands may be correlatedlikewise with deects induced by the charge transer reactionbetween the polymer chain and the dopant Te vibrational

peaks at 983091983093983096983088 983090983097983095983092 983089983095983092983088 983089983092983094983088 and 983096983092983093 cmminus1 are assignedto OndashH stretching CndashH stretching C=O stretching CndashH

bend o CH2 and CH rocking o PVA respectively [983091983097983092983088] Further the vibrational peaks ound in the range 983089983089983091983088ndash

983094983093983088 cmminus1 may be attributed to AgndashO which indicate thatsilver nanoparticles doped in the PVA polymer matrix [983091983095]Te experimental data given in Figure 983092 indicate an increasein the vibrations o OndashH CndashH and C=O groups in the PVAmatrix afer adding Ag nanoparticles directly in the PVA1047297lm Such changes in OndashH CndashH and C=O vibrations have

been observed in other report [983092983088] Afer doping Ag somepolymers chains have been broken and some other chainshave been ormed instead Increasing the FIR spectrum in

the range o 983089983092983088983088 to 983089983094983088983088 cmminus1 corresponds to CndashH bondo CH2 and shows the broken chains Ag nanoparticles havegenerated new bonds in this range Decreasing the FIR

spectrum in the range o 983090983093983088983088 to 983091983095983088983088 cmminus1 shows theproduced polymerchains corresponds to OndashH stretching andCndashH stretching bonds

Te variation o transmittance () and re1047298ectance ()as a unction o wavelength or pure PVA polymer 1047297lmand samples 983089 to 983091 were recorded at room temperature and

7272019 pva films

httpslidepdfcomreaderfullpva-films 511

Journal o Nanomaterials 983093

500 1000 1500 2000 2500 3000 3500 40000

20

40

60

80

100

120

T

r a n s m i t t a n c e

Wavenumbers (cmminus1)

PVA

S1

S2

S3

F983145983143983157983154983141 983092 FIR spectrum o PVA pure 1047297lm and Ag nanoparticledoped in PVA polymer 1047297lms

200 400 600 800 1000 1200 1400 1600 1800 20000

01

02

03

04

05

06

07

0809

1

Wavelength (nm)

PVA

S1

S2

S3

Transmittance

Re1047298ectance

F983145983143983157983154983141 983093 Optical transmittance and re1047298ectance spectrum o sam-ples

are shown in Figure 983093 Pure PVA is a colorless polymerwithout any noticeable absorption in the visible range Tesharp increase observed in transmittance spectrum in therange o 983090983089983088 to 983090983092983096 nm is due to the presence o the PVApolymer bandgap [983089] Tis 1047297gure clearly indicates that aferadding nano-Ag in PVA polymer a valley at 983092983089983097 nm hasbeen created that its intensity continuously increasing withincreasing concentration o the dopant Tis new valley is

attributed to the ormation o charge transer complexes [983092983089]Te appearance o this valley in the visible region is dueto the surace plasmon resonance (SPR) nature o the Agnanoparticles embedded in PVA polymer dielectric medium

Aferdoping Ag nanoparticles in PVA polymer the re1047298ec-tion with increasing concentration o silver nanoparticlesdue to local 1047298uctuations charged particles declined

Te optical absorption coefficients o samples are evalu-ated rom the transmittance data using [983092983090]

1038389 = 1 ln 1048667

983131

(1 minus )22 + radic (1 minus )442 + 21048669

983133

(983089)

0 1 2 3 4 5 6 70

5

10

15

20

25

30

35

40

Photon energy (eV)

PVA

S1

S2

S3

A b s o r p t i o n

c o e

ffi c i e n t ( m m minus 1 )

F983145983143983157983154983141 983094 Optical absorption coefficient o 1047297lms

where and are the transmittance and re1047298ection respec-tively 1038389 is the absorption coefficient and is the thickness o the 1047297lms Figure 983094 presents the optical absorption coefficientsor undoped and nano-Ag doped PVA 1047297lms versus photonenergies Te absorption peak at 983090983097983093 eV or Ag nanoparticlesdoped in PVA polymer 1047297lms represents the characteristicsurace plasmon resonance dedicated to silver nanoparticlesTe presence o nanoparticles in the polymer 1047297lms could beconveniently ollowed by monitoringthe plasmon absorptionpeaks in the absorption spectrum Te larger absorptionpeak appeared in UV range is due to the energy gap o the PVA polymer which decreases owing to increasing theconcentration o Ag nanoparticles in the structure o the1047297lms Te position o the absorption edge was determinedby extrapolating the linear part o 1038389 versus ℎ] curves to zeroabsorption value [983092983089] Te band edge showed a decrease withincreasing concentration o Ag nanoparticles in PVA matrixTe absorption edge shifs towards higher wavelength indi-cating the decrease in the optical bandgap orthe doped 1047297lmsShifo the absorptionedgein the UVregionis due tochangesin the electron hole in the conduction and valence bands

Te most used method or estimation o the bandgapenergy rom optical measurement is the one proposed by auc and Grigorovici [983092983091] Te optical bandgap energy o samples was deduced rom the intercept o the extrapolated

linear part o the plot o (1038389)12 versus the photon energy with abscissa (Figure 983095) Tis ollows by the method o aucwhere

1038389 = 1048616 minus 10486171038389 (983090)

In this equation 1038389() is the absorption coefficient isthe photon energy is a actor that depends on transitionprobability and can be assumed to be constant within theoptical requency range and the index that is related tothe distribution o the density o states is an index whichassumes the values 983089983090 983091983090 983090 and 983091 depending on the natureo electronic transition aking = 2 which correspondsto indirectly allowed transition in pure PVA 1047297lm and nano-Ag doped PVA 1047297lms the bandgap energies o 1047297lms were

7272019 pva films

httpslidepdfcomreaderfullpva-films 611

983094 Journal o Nanomaterials

0 1 2 3 4 5 6 70

2

4

6

8

10

12

14

16

Photon energy (eV)

( 1038389 E ) 1 2

( m m minus 1 2 e V 1 2 )

PVA

S1

S2

S3

F983145983143983157983154983141 983095 (1038389)12 versus photon energy to illustrate auc method

calculated In an indirect gap a photon cannot be emittedbecause the electron must pass through an intermediatestate and transer momentum to the crystal lattice Teenergy gap o pure PVA sample is equal to 983092983097983094 eV andwith increasing the concentration o the Ag-nanoparticlesin the structure o 1047297lms bandgap energy is decreased Teextracted bandgap energy o sample are 983092983096983095 983092983096983092 and983092983095983096 eV or sample 983089ndash983091 respectively Te incorporation o the silver nanoparticles irrespective o their methodology o synthesis also affects the bandgap o the involved polymersystem Tis also con1047297rms the presence o the inorganic1047297llers inside the host [983089] Te variation o the calculated

values o optical bandgap re1047298ects the role o ormationo Ag-nanoparticles in modiying the electronic structureo the PVA matrix [983092983089 983092983092] Tese Ag-nanoparticles may be responsible or the ormation o localized electronicstates in the Highest Occupied Molecular Orbital-LowestUnoccupied Molecular Orbital (HOMO-LUMO) gap Teselocalized electronic states dominate the optical and electricalproperties vis-a-vis their role as trapping and recombinationcenters thus enhancing the low energy transitions leadingto the observed change in optical bandgap Te decrease inthe optical bandgap also re1047298ects the increase in the degreeo disorder in the 1047297lms which arises due to the change inpolymer structure [983092983092 983092983093]

Optical properties such as complex reractive index anddielectric constant or a certain range o wavelength betweenultraviolet and near inrared are important criteria or theselection o abricated 1047297lms or various applications Tereractive index is one o the undamental properties o a material because it is closely related to the electronicpolarizability o ions and the local 1047297eld inside the material [983096983097] Tus to urtherunderstand the interaction o Ag nanopar-ticles with PVA matrix optical properties such as complexreractive index and dielectric constant have been calculatedusing the undamental relations o photon transmittance ()re1047298ectance () and absorbance () Te complex reractiveindex is

= + that

is the real part and the extinction

0 1 2 3 4 5 6 713

14

15

16

17

18

19

2

Photon energy (eV)

R e f r a c t i v e i n d e x

PVA

S1

S2

S3

F983145983143983157983154983141 983096 Te reractive index o 1047297lms

coefficient

is the imaginary part Te reractive index

o

the 1047297lms was calculated using the ollowing equation [983092983094]

= 9830801 + 1 minus 983081 + radic 4(1 minus )2 minus 2 (983091)

in which = 110392510383894 Figures 983096 and 983097 show the photonenergy dependence o reractive index and the extinctioncoefficient or pure PVA and nano-Ag doped PVA 1047297lms Itcan be discerned rom Figure 983096 that the reractive index o nano-Ag doped PVA 1047297lms is lower than the reractive indexo pure PVA and it decreases with increasing concentrationo Ag nanoparticles in PVA matrix Tis property is inherentin all conductors and due to localized 1047298uctuation o charged

particles in medium Also decreasing the value o reractiveindex may be an indication o low density o 1047297lms whichleads to increasing the interatomic spacing [983092983093]Tisisduetoormation o intermolecular hydrogen bonding between Ag-nanoparticles and the adjacent OH groups Te dependenceo the reractive index on the 1047297lm density can be discussed by the well-known Clausius-Mossotti relation [983092983094]

Te extinction coefficient describes the properties o the material with respect to light o a given wavelength andindicates the absorption changes when the electromagneticwavepropagates through the material In Figure 983097 the extinc-tion coefficient o the doped samples have a peak at =295 eV which increases with increasing concentration o Ag nanoparticles in PVA dielectric medium Te extinctioncoefficient increases due to surace plasmon absorption indoped samples while the reractive index decreases in thisregion Tere is anomalous dispersion regions when 225 lt lt 2983097983093 eV and gt 485 eV as well as normal dispersionwhen 295 lt lt 345 eV or doped samples

Te complex dielectric unction is = 1103925 + 907317 where1103925 is the real part and 907317 is the imaginary part o dielectricconstant Te real and imaginary parts o dielectric constantare expressed as

1103925 = 2 minus 2907317 = 2 (983092)

7272019 pva films

httpslidepdfcomreaderfullpva-films 711

Journal o Nanomaterials 983095

0 1 2 3 4 5 6 70

1

2

3

4

5

6

7

8

Photon energy (eV)

E x t i n c t i o

n c o e

ffi c i e n t

PVA

S1

S2

S3

times10minus4

F983145983143983157983154983141 983097 Te extinction coefficient spectrum o 1047297lms

0 1 2 3 4 5 6 715

2

25

3

35

4

Photon energy (eV)

PVA

S1

S2

S3

1103925 r

F983145983143983157983154983141 983089983088 Real part o the dielectric constant o pure PVA and Agnanoparticle doped 1047297lms

Te real part o dielectric constant is related to the disper-sion In order to explain the dispersion it is necessary to takeinto account the actual motion o the electrons in the opticalmedium through which the light is traveling Te imaginary part represents the dissipative rate o electromagnetic wavepropagation in the medium Te real and imaginary partsdependences on photon energy o samples are shown in

Figures 983089983088 and 983089983089 respectively It can be concluded that 1103925is larger than 907317 because it mainly depends on 2 Withincreasing the amount o silver nanoparticles in PVA the realpart o dielectric constant is decreased It is due to decreaseo the dielectric property o 1047297lms because o Ag nanoparticlesmetal lattice in the host PVA polymer matrix Te normaldispersion is associated with an increase in Re() with andanomalous dispersion is associated with the reverse mecha-nism Normal dispersion is occurred everywhere expect inthe neighborhood o the resonance requency In this regionthe anomalous dispersion is appreciable Since a positiveimaginary part to 907317 represents dissipation o energy rom theelectromagnetic wave into the medium the regions where

907317

0 1 2 3 4 5 6 70

05

1

15

2

25

Photon energy (eV)

PVA

S1

S2

S3

times10minus3

1103925 i

F983145983143983157983154983141 983089983089 Imaginary part o the dielectric unction o 1047297lms

is large are called regions o resonant absorption [983092983095] Tepeak that appears in Figure 983089983089 at = 295 eV shows theplasmonic absorption

Te complex dielectric unction and complex opticalconductivity are introduced through Maxwellrsquos equationsTe interband transitions have threshold energy at the energy gap Tat is we expect the requency dependence o thereal part o the conductivity 1103925() due to an interbandtransition to exhibit a threshold or an allowed electronictransition [983092983096] In interband transition real 1103925 and imaginary 907317 components o optical conductivity are described as [983092983096ndash983093983088]

1103925 = 9073170907317 = 11039250 (983093)

where is the angular requency o electromagnetic wave and0 is the ree space dielectric constant Te real and imaginary parts o the optical conductivity dependence on the photonenergy are shown in Figures 983089983090 and 983089983091 respectively

Te real optical conductivity in bandgap energy regionafer doping the Ag-nanoparticles in PVA polymer decreasesIt can be due to the segregation effect [983092983089 983093983089] Te segregatedeffect is the dispersion o metallic particles restricted by thepresence o much larger polymeric particles Te observedeffect o Ag nanoparticles on the optical conductivity and

conduction behavior o PVA 1047297lms can be explained on thebasis o charge transer complex ormation involving PVAmolecules and the dopant When PVA polymer is mixedwith Ag nanoparticles as a result the 1047297ller is pushed intointerstitial space between the polymer particles and ormsa segregated network [983093983089] At higher dopant concentrationthere may be segregation o the dopant in the polymermatrix which decreases the conductivity Tus motion o charge carriers or localized 1047298uctuations o charged parti-cles in molecular aggregates impedes optical conductivityMoreover there is a weak peak at = 295 eV that can beseen only in the doped samples Tis new peak is attributedto the ormation o charge transer or the surace plasmon

7272019 pva films

httpslidepdfcomreaderfullpva-films 811

983096 Journal o Nanomaterials

0 1 2 3 4 5 6 70

02

04

06

08

1

12

14

16

18

2

Energy photon (eV)

PVA

S1

S2

S3

times10minus16

907317 r

( S m )

F983145983143983157983154983141 983089983090 Real part o the optical conductivity o pure PVA anddoped 1047297lms

0 1 2 3 4 5 6 70

05

1

15

2

25

3

35

Energy photon (eV)

PVA

S1

S2

S3

times10minus13

907317 i

( S m )

F983145983143983157983154983141 983089983091 Imaginary part o the optical conductivity o pure PVAand doped 1047297lms

silver nanoparticles Another result is that by increasingthe concentration o Ag nanoparticles in PVA matrix theimaginary part o optical conductivity decreases

A dielectric sample in an external electric 1047297eld acquiresa nonzero macroscopic dipole moment indicating that thedielectric is polarized under the in1047298uence o the 1047297eld Polar-ization o dielectric material achieves its equilibrium valuenot instantaneously but rather over a period o time [983093983090]Te dielectric relaxation time can be evaluated using

= infin minus 1103925907317 (983094)

Figure 983089983092 shows the dielectric relaxation time as a unc-tion o photon energy or pure PVA polymer and Agnanoparticle doped PVA 1047297lms Te valley at 983090983097983093 eV ordoped samples increases with increasing the concentrationo Ag nanoparticles in the structure o the 1047297lms In otherwords the relaxation time o dipole orientation decreases

2 25 3 35 4 45 5 550

02

04

06

08

1

12

14

16

18

2

Photon energy (eV)

R e

l a x a t

i o n t i m e

( s )

PVA

S1

S2

S3

times10minus12

F983145983143983157983154983141 983089983092 Relaxation time versus photon energy o 1047297lms

Tis is another reason or decreasing the dielectric unctionand increasing the conductivity o 1047297lms with increasing theconcentration o nanoparticles in their structure [983093983091]

Reractive index dispersion is a determinant actor inoptical materials It is a signi1047297cant actor in opticalcommuni-cation andin designingdevices orspectral dispersion[983091983093]Inthe normal dispersion region the reractive index dispersionhasbeen analyzed using thesingleoscillator model developedby theory o Wemple and DiDomenico [983093983092] Tey intro-duced a dispersion-energy parameter which connectsthe coordination number and the charge distribution withineach unit cell

is closely related to chemical bonding

Also they de1047297ned a single oscillator parameter 0 whichis proportional to the energy o oscillator In terms o thisdispersion energy and single oscillator energy 0 thereractive index at requency can be written as

12 minus 1 = 0

minus 10

(ℎ])2 (983095)

Te values o and 0 can be obtained rom the

intercept and slope o the linear part o (2 minus 1)minus1 plot versus

(ℎ]

)2 as is shown in Figure 983089983093 Also dispersion o reractive

index is controlled by the combined effects o and 0 Tecalculated values o the dispersion parameters (0 and )as well as the corresponding optical constant ( = 2) orthe pure PVA 1047297lm and samples 983089 to 983091 are listed in able 983089Te dispersion energy values decreases with increasing theconcentration o Ag nanoparticles in PVA 1047297lms because theanion strength o the dielectric medium has been declinedTereore the PVA polymer host is less willing to keep theelectrons in their outer layers Te single oscillator energy isan average energy gap as pointed out in many reerences [983093983088]Te 0 value o the 1047297lms is related empirically to the lowestindirect bandgap by 0 asymp 103 Tis relation is in goodagreement with the single oscillator model

7272019 pva films

httpslidepdfcomreaderfullpva-films 911

Journal o Nanomaterials 983097

10 105 11 115 12 125 1302

04

06

08

1

12

14

16

PVA

S1

S2

S3

(

n 2

minus

1 ) minus 1

E2 (eV2)

F983145983143983157983154983141 983089983093Plot o (2minus1) versus squared photon energy o pure PVAand doping samples

983137983138983148983141 983089 Dispersion parameters o 1047297lmsSamples 0

PVA 983089983093983094 983090983092983092 983093983089983097 983095983092983097

S983089 983089983092983096 983090983089983097 983093983088983092 983094983088983091

S983090 983089983091983095 983089983096983097 983092983097983095 983092983092983094

S983091 983089983089983097 983089983092983090 983092983096983095 983090983088983093

4 Conclusions

Preparation o silver nanoparticles by laser ablation methodat different 1047298uencies o laser pulse in pure water is investi-gated Te EM analysis revealed that generated nanoparti-

cles in this experimental condition are almost spherical andtheir average size was 983094ndash983089983090 nm and with increasing the laserpulse 1047298uence the size o nanoparticles is decreased Te X-ray diffraction spectrum reveals that the number o crystal-lographic planes at certain angles is increased afer doping Agnanoparticles in the structure o PVA FIR spectrum peakscorrespond to molecular vibrations and chemical bondsindicate the presence o silver in the PVA polymer structureTe optical bandgap energy o the samples is decreasedwith increasing the concentrations o silver nanoparticlesReractive index and dielectric constant are decreased withincreasing the concentration o Ag nanoparticles Increaseo dopant concentration resulted in a decrease in real part

o the optical conductivity because o segregation effectTe reractive index and consequently the related dispersionparameters o PVA and doped PVA have been determinedand explained using the Wemple-DiDomenico model

References

[983089] A Nimrodh Ananth and S Umapathy ldquoOn the optical andthermal properties o in situex situ reduced Ag NPrsquosPVAcomposites and its role as a simple SPR-based protein sensorrdquo Applied Nanoscience vol 983089 no 983090 pp 983096983095ndash983097983094 983090983088983089983089

[983090] G Nesher G Marom and D Avnir ldquoMetal-polymer compos-ites synthesis and characterization o polyaniline and other

polymer at Silver compositionsrdquo Chemistry of Materialsvol983090983088no 983089983091 pp 983092983092983090983093ndash983092983092983091983090 983090983088983088983096

[983091] P-H Wang Y-Z Wu andQ-R ZhuldquoPolymermetal compositeparticles polymer core and metal shellrdquo Journal of MaterialsScience Letters vol 983090983089 no 983090983091 pp 983089983096983090983093ndash983089983096983090983096 983090983088983088983090

[983092] S Clemenson P Alcouffe L David and E Espuche ldquoStructureand morphology o membranes prepared rom polyvinyl alco-hol and silver nitrate in1047298uence o the annealing treatment ando the 1047297lm thicknessrdquo Desalination vol 983090983088983088 no 983089-983091 pp 983092983091983095ndash983092983091983097 983090983088983088983094

[983093] K Akamatsu S akei M Mizuhata et al ldquoPreparation andcharacterization o polymer thin 1047297lms containing silver andsilver sul1047297de nanoparticlesrdquo Tin Solid Films vol 983091983093983097 no 983089 pp983093983093ndash983094983088 983090983088983088983088

[983094] R Zeng M Z Rong M Q Zhang H C Liang and H MZeng ldquoLaser ablation o polymer-based silver nanocompositesrdquo Applied Surface Science vol 983089983096983095 no 983091-983092 pp 983090983091983097ndash983090983092983095 983090983088983088983090

[983095] S Mahendia A K omar and S Kumar ldquoElectrical conduc-tivity and dielectric spectroscopic studies o PVA-Ag nanocom-posite 1047297lmsrdquo Journal of Alloys and Compounds vol 983093983088983096 no 983090pp 983092983088983094ndash983092983089983089 983090983088983089983088

[983096] N Singh and P K Khanna ldquoIn situ synthesis o silver nano-particles in polymethylmethacrylaterdquo Materials Chemistry and Physics vol 983089983088983092 no 983090-983091 pp 983091983094983095ndash983091983095983090 983090983088983088983095

[983097] P K Khanna R Gokhale V V V S Subbarao A K Vish-wanath B K Das and C V V Satyanarayana ldquoPVA stabilizedgold nanoparticles by use o unexplored albeit conventionalreducing agentrdquo Materials Chemistry and Physics vol 983097983090 no983089 pp 983090983090983097ndash983090983091983091 983090983088983088983093

[983089983088] K Akamatsu S akei M Mizuhata et al ldquoPreparation andcharacterization o polymer thin 1047297lms containing silver andsilver sul1047297de nanoparticlesrdquo Tin Solid Films vol 983091983093983097 no 983089 pp983093983093ndash983094983088 983090983088983088983088

[983089983089] I Hussain M Brust A J Papworth and A I Cooper

ldquoPreparationo acrylate-stabilized goldand silver hydrosols andgold-polymer composite 1047297lmsrdquo Langmuir vol 983089983097 no 983089983089 pp983092983096983091983089ndash983092983096983091983093 983090983088983088983091

[983089983090] S A Zavyalov A N Pivkina and J Schoonman ldquoFormationand characterization o metal-polymer nanostructured com-positesrdquo Solid State Ionics vol 983089983092983095 no 983091-983092 pp 983092983089983093ndash983092983089983097 983090983088983088983090

[983089983091] J Lee D Bhattacharyya A J Easteal and J B Metson ldquoProp-erties o nano-ZnOpoly(vinyl alcohol)poly(ethylene oxide)composite thin 1047297lmsrdquo Current Applied Physics vol 983096 no 983089 pp983092983090ndash983092983095 983090983088983088983096

[983089983092] Z Zhong D Wang Y Cui M W Bockrath and C H LieberldquoNanowire crossbar arrays as address decoders or integratednanosystemsrdquo Science vol 983091983088983090 no 983093983094983092983097 pp 983089983091983095983095ndash983089983091983095983097 983090983088983088983091

[983089983093] D S Hopkins D Pekker P M Goldbart and A Bezryadin

ldquoQuantum intererence device made by DNA templating o superconducting nanowiresrdquo Science vol 983091983088983096 no 983093983095983090983097 pp983089983095983094983090ndash983089983095983094983093 983090983088983088983093

[983089983094] S Clemenson D Leonard D Sage L David and E EspucheldquoMetal nanocomposite 1047297lms prepared in Situ rom PVA andsilver nitrate Study o the nanostructuration process andmorphology as a unction o the in Situ routesrdquo Journal of Polymer Science A vol 983092983094 no 983094 pp 983090983088983094983090ndash983090983088983095983089 983090983088983088983096

[983089983095] M K emgire and S S Joshi ldquoOptical and structural studies o silver nanoparticlesrdquo Radiation Physics and Chemistry vol 983095983089no 983093 pp 983089983088983091983097ndash983089983088983092983092 983090983088983088983092

[983089983096] M Zheng M Gu Y Jin and G Jin ldquoOptical properties o silver-dispersed PVP thin 1047297lmrdquo Materials Research Bulletin vol 983091983094no 983093-983094 pp 983096983093983091ndash983096983093983097 983090983088983088983089

7272019 pva films

httpslidepdfcomreaderfullpva-films 1011

983089983088 Journal o Nanomaterials

[983089983097] O L A Monti J Fourkas and D J Nesbitt ldquoDiffraction-limited photogeneration and characterization o silver nanopar-ticlesrdquo Journal of Physical Chemistry B vol 983089983088983096 no 983093 pp 983089983094983088983092ndash983089983094983089983090 983090983088983088983092

[983090983088] K L Kelly E Coronado L L Zhao and G C Schatz ldquoTeopti-cal properties o metal nanoparticles the in1047298uence o sizeshape and dielectric environmentrdquo Journal of Physical Che-

mistry B vol 983089983088983095 no 983091 pp 983094983094983096ndash983094983095983095 983090983088983088983091

[983090983089] H Weickmann J C iller R Tomann and R MulhauptldquoMetallized organoclays as new intermediates or aqueous nan-ohybrid dispersions nanohybrid catalysts and antimicrobialpolymer hybrid nanocompositesrdquo Macromolecular Materialsand Engineering vol 983090983097983088 no 983097 pp 983096983095983093ndash983096983096983091 983090983088983088983093

[983090983090] U Keirbeg and M Vollmer Optical Properties of Metal Clusters vol 983090983093 o Springer Series in Material Science 983089983097983097983093

[983090983091] S Chen and J M Sommers ldquoAlkanethiolate-protected coppernanoparticles spectroscopy electrochemistry and solid-statemorphological evolutionrdquo Journal of Physical Chemistry B vol983089983088983093 no 983091983095 pp 983096983096983089983094ndash983096983096983090983088 983090983088983088983089

[983090983092] A A Scalisi G Compagnini L DrsquoUrso and O Puglisi ldquoNon-linearopticalactivity in Ag-SiO

2 nanocomposite thin 1047297lms with

different silver concentrationrdquo Applied Surface Science vol 983090983090983094no 983089ndash983091 pp 983090983091983095ndash983090983092983089 983090983088983088983092

[983090983093] G Yang W Wang Y Zhou H Lu G Yang and Z Chen ldquoLin-ear and nonlinear optical properties o Ag nanoclusterBaiO3

composite 1047297lmsrdquo Applied Physics Letters vol 983096983089 no 983090983089 pp983091983097983094983097ndash983091983097983095983089 983090983088983088983090

[983090983094] H B Liao R F Xiao H Wang K S Wong and G K L WongldquoLarge third-order optical nonlinearity in AuiO2 composite1047297lms measured on a emtosecond time scalerdquo Applied PhysicsLetters vol 983095983090 no 983089983093 pp 983089983096983089983095ndash983089983096983089983097 983089983097983097983096

[983090983095] A K Sarychev D J Bergman and Y Yagil ldquoTeory o theoptical and microwave properties o metal-dielectric 1047297lmsrdquoPhysical Review B vol 983093983089 no 983096 pp 983093983091983094983094ndash983093983091983096983093 983089983097983097983093

[983090983096] G Mie ldquoBeitrage zur Optik truber Medien speziell kolloidalerMetallosungenrdquo Annalen der Physik vol 983091983091983088 pp 983091983095983095ndash983092983092983093 983089983097983088983096

[983090983097] R Gans ldquoUber die Form ultramikroskopischer Silberteilchenrdquo Annalen der Physik vol 983091983093983090 no 983089983088 pp 983090983095983088ndash983090983096983092 983089983097983089983093

[983091983088] S Link and M A El-Sayed ldquoSpectral properties and relaxationdynamics o surace plasmon electronic oscillations in gold andsilver nanodots and nanorodsrdquo Journal of Physical Chemistry B vol 983089983088983091 no 983092983088 pp 983096983092983089983088ndash983096983092983090983094 983089983097983097983097

[983091983089] G Fussell J Tomas J Scanlon A Lowman and M Mar-colongo ldquoTe effect o protein-ree versus protein-containingmedium on the mechanical properties and uptake o ions o PVAPVP hydrogelsrdquo Journalof BiomaterialsScience vol983089983094 no983092 pp 983092983096983097ndash983093983088983091 983090983088983088983093

[983091983090] suji Mizuki S Ozono and M suji ldquoLaser-induced sil-

ver nanocrystal ormation in polyvinylpyrrolidone solutionsrdquo Journal of Photochemistry and Photobiology A vol 983090983088983094 no 983090-983091pp 983089983091983092ndash983089983091983097 983090983088983088983097

[983091983091] J-P Sylvestre S Poulin A V Kabashin E Sacher M Meunierand J H Luong ldquoSurace chemistry o gold nanoparticlesproduced by laser ablation in aqueous mediardquo Journal of Physical Chemistry B vol 983089983088983096 no 983092983091 pp 983089983094983096983094983092ndash983089983094983096983094983097 983090983088983088983092

[983091983092] A Gautam and S Ram ldquoPreparation and thermomechanicalproperties o Ag-PVA nanocomposite 1047297lmsrdquo Materials Chem-istry and Physics vol 983089983089983097 no 983089-983090 pp 983090983094983094ndash983090983095983089 983090983088983089983088

[983091983093] I Saini J Rozra N Chandak S Aggarwal P K Sharmaand A Sharma ldquoailoring o electrical optical and structuralproperties o PVA by addition o Ag nanoparticlesrdquo MaterChem Phys vol 983089983091983097 pp 983096983088983090ndash983096983089983088 983090983088983089983091

[983091983094] S Mahendia A K omar and S Kumar ldquoNano-Ag dopinginduced changes in optical and electrical behaviour o PVA1047297lmsrdquo Materials Science and Engineering B vol 983089983095983094 no 983095 pp983093983091983088ndash983093983091983092 983090983088983089983089

[983091983095] M Abdelaziz and E M Abdelrazek ldquoEffect o dopant mixtureon structural optical and electron spin resonance properties o polyvinyl alcoholrdquo Physica B vol 983091983097983088 no 983089-983090 pp 983089ndash983097 983090983088983088983095

[983091983096] B Suo X Su J Wu D Chen A Wang and Z Guo ldquoPoly (vinyl alcohol) thin 1047297lm 1047297lled with CdSe-ZnS quantum dotsabrication characterization and optical propertiesrdquo MaterialsChemistry and Physics vol 983089983089983097 no 983089-983090 pp 983090983091983095ndash983090983092983090 983090983088983089983088

[983091983097] B Karthikeyan ldquoSpectroscopic studies on Ag-polyvinyl alcoholnanocomposite 1047297lmsrdquo Physica B vol 983091983094983092 no 983089ndash983092 pp 983091983090983096ndash983091983091983090983090983088983088983093

[983092983088] A S Kutsenko and V M Granchak ldquoPhotochemical synthesiso silver nanoparticles in polyvinyl alcohol matricesrdquo Teoreti-cal and Experimental Chemistry vol 983092983093no 983093 pp 983091983089983091ndash983091983089983096983090983088983088983097

[983092983089] C U Devi A K Sharma and V V R N Rao ldquoElectrical andoptical properties o pure and silver nitrate-doped polyvinylalcohol 1047297lmsrdquo Materials Letters vol 983093983094 no 983091 pp 983089983094983095ndash983089983095983092 983090983088983088983090

[983092983090] B G Streetman Solid State Electronic Devices Prentice HallNew Jersey NJ USA 983091rd edition 983089983097983097983088

[983092983091] J auc and R Grigorovici ldquoOptical properties and electronicstructure o amorphous germaniumrdquo Physica Status Solidi (B) vol 983089983093 no 983090 pp 983094983090983095ndash983094983091983095 983089983097983094983094

[983092983092] J Rozra I Saini A Sharma et al ldquoCu nanoparticles inducedstructural optical and electrical modi1047297cation in PVArdquo Materi-als Chemistry and Physics vol 983089983091983092 no 983090-983091 pp 983089983089983090983089ndash983089983089983090983094 983090983088983089983090

[983092983093] M Abdelaziz ldquoCerium (III) doping effects on optical andthermal properties o PVA 1047297lmsrdquo Physica B vol 983092983088983094 no 983094-983095pp 983089983091983088983088ndash983089983091983088983095 983090983088983089983089

[983092983094] C Kittle Introduction to Solid State Physics vol 983092983088983093 John Wiley amp Sons New York NY USA 983089983097983095983089

[983092983095] J D Jackson Classical Electrodynamics John Wiley amp Sons 983091rdedition 983089983097983097983097

[983092983096] M S Dresselhaus Solid State Physics Part II Optical Propertiesof Solids vol 983094 983090983088983088983089

[983092983097] J N Hodgson Optical Absorption and Dispersion in Solids Chapman amp Hall London UK 983089983097983095983089

[983093983088] Y Caglar S Ilican and M Caglar ldquoSingle-oscillator modeland determination o optical constants o spray pyrolyzedamorphous SnO2 thin 1047297lmsrdquo European Physical Journal B vol983093983096 no 983091 pp 983090983093983089ndash983090983093983094 983090983088983088983095

[983093983089] Y Seok Kim Electrical Conductivity of Segregated NetworkPolymer Nanoposites vol 983089983091983095 983090983088983088983095

[983093983090] Y Feldman A Puzenko and Y Ryabov ldquoDielectric relaxationphenomena in complex materialsrdquo in Advances in Chemical

Physics vol 983089983091983091 pp 983089ndash983089983090983093 Department o Applied Physics TeHebrew University o Jerusalem Jerusalem Israel 983090983088983088983094

[983093983091] S Mahendia A K omar R P Chahal P Goyal and S KumarldquoOptical and structural properties o poly(vinyl alcohol) 1047297lmsembedded with citrate-stabilized gold nanoparticlesrdquo Journal of Physics D vol 983092983092 no 983090983088 Article ID 983090983088983093983089983088983093 983090983088983089983089

[983093983092] S H Wemple and M DiDomenico ldquoBehavior o the electronicdielectric constant in covalent and ionic materialsrdquo Physical Review B vol 983091 no 983092 pp 983089983091983091983096ndash983089983091983093983089 983089983097983095983089

7272019 pva films

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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2013Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The ScientifcWorld Journal

Impact Factor 1730

28 Days Fast Track Peer Review

All Subject Areas of Science

Submit at httpwwwtswjcom

7272019 pva films

httpslidepdfcomreaderfullpva-films 311

Journal o Nanomaterials 983091

4 6 8 10 12 14 16 18 20 220

5

10

15

Size of Ag nanoparticles (nm)

S t a t i s t i c a

l d i s t r i b u t i o n

40nm

(a)

4 6 8 10 12 14 16 18 20 220

1

2

3

4

5

6

Size of Ag nanoparticles (nm)

S t a t i s t i c a l d i s t r i b u t i o n

40nm

(b)

4 6 8 10 12 14 16 18 20 220

5

10

15

Size of Ag nanoparticles (nm)

S t a t i s t i c a

l d i s t r i b u t i o n

40nm

(c)

F983145983143983157983154983141 983090 EM image and size distribution o Ag nanoparticle generated in distilled water with laser ablation method (a) S983089 (b) S983090 and (c)S983091

XRD spectrum o the Ag nanoparticles and pure PVApolymer 1047297lms and PVA doped Ag nanoparticles are shownin Figures 983091(a)ndash983091(c) Te diffraction pattern o undopedPVA indicates a diffraction bands at 2907317 = 1388∘ 983089983094983095983094∘983090983093983092∘ 983092983090983089983090∘ and 983092983096983096983096∘ It is well known that the peaks at2907317 lt 20∘ are due to crystalline nature o PVA polymermolecules which may be as a result o strong intermolecularand intramolecular hydrogen banding between the PVAchains [983095 983091983092] Te peaks at angles larger than 983090983088 ∘ may be due to impurities Te X-ray diffraction peaks o Agnanoparticles occur at 2907317 = 3815∘ 983092983092983091983097∘ 983094983092983095983092∘ 983095983095983093∘and 983096983089983094∘ corresponding to re1047298ections rom the ⟨111⟩ ⟨200⟩

⟨220⟩ ⟨311⟩ and ⟨222⟩ planes o Ag FCC lattice structurerespectively [983091983093 983091983094] All peaks observed in the sample o Ag nanoparticles have also been recreated in polymer 1047297lmsdoped with silver nanoparticles Te peaks o polymer X-ray diffraction pattern at 2907317 gt 20∘ have been removed aferdoping Te peak at 2907317 = 4212∘ in pure PVA is observed toshif up by about 983090983093∘ degree in PVA doped Ag nanoparticlesTis shif might be due to changes in the spacing valueso the corresponding planes Te intensity o diffracted X-ray photons rom 1047297lms has been increased noticeably afer thedoping process It may be due to two reasons For 2907317 lt 20∘increasing the peaks intensity is dueto increasing the number

7272019 pva films

httpslidepdfcomreaderfullpva-films 411

983092 Journal o Nanomaterials

10 20 30 40 50 60 70 80 90

0

500

1000

1500

2000

I n t e n s i t y

( a u )

Ag nanoparticles

PVA polymer

S1

2 (∘)

minus500

(a) S983089 (983089983093Jcm2)

10 20 30 40 50 60 70 80 90

0

500

1000

1500

2000

I n t e n s i t y

( a u )

Ag nanoparticles

PVA polymer

S2

2 (∘)

minus500

(b) S983090 (983090 Jcm2)

10 20 30 40 50 60 70 80 90

0

500

1000

1500

2000

I n t e n s i t y

( a u )

Ag nanoparticles

PVA polymer

S3

2 (∘)

minus500

(c) S983091 (983091 Jcm2)

F983145983143983157983154983141 983091 X-ray diffraction patterns o Ag nanoparticles PVA polymer and Ag nanoparticle doped PVA 1047297lms (a) S983089 (b) S983090 and (c) S983091

o PVA chains afer Ag doping Decreasing the intensity o peaks in FIR spectrum con1047297rms that afer doping numbero PVA chains are increased in the structure o the 1047297lmsSame results have been observed by Mahendia et al andGautam and Ram [983095 983091983092] For 2907317 gt 20∘ increasing theintensity o XRD peaks is due to increasing the number o crystallographic planes at certain angles

Te Fourier transorm inrared spectroscopy (FIR)

spectra o pure PVA and doped 1047297lms are shown in Figure 983092All spectra exhibit the characteristic absorption bands o purePVA which are 983091983093983096983088 983090983097983095983092 983089983095983092983088 983089983093983095983088 983089983092983094983088 and 983096983092983093 cmminus1

[983091983095 983091983096] It can be noticed that these treatments cause someobservable changes in the spectral eatures o the samples

in the range 983089983089983088983088ndash983093983088983088 cmminus1 (1047297ngerprint region) apart romnew absorption bands and slight changes in the intensitieso some absorption bands Te new bands may be correlatedlikewise with deects induced by the charge transer reactionbetween the polymer chain and the dopant Te vibrational

peaks at 983091983093983096983088 983090983097983095983092 983089983095983092983088 983089983092983094983088 and 983096983092983093 cmminus1 are assignedto OndashH stretching CndashH stretching C=O stretching CndashH

bend o CH2 and CH rocking o PVA respectively [983091983097983092983088] Further the vibrational peaks ound in the range 983089983089983091983088ndash

983094983093983088 cmminus1 may be attributed to AgndashO which indicate thatsilver nanoparticles doped in the PVA polymer matrix [983091983095]Te experimental data given in Figure 983092 indicate an increasein the vibrations o OndashH CndashH and C=O groups in the PVAmatrix afer adding Ag nanoparticles directly in the PVA1047297lm Such changes in OndashH CndashH and C=O vibrations have

been observed in other report [983092983088] Afer doping Ag somepolymers chains have been broken and some other chainshave been ormed instead Increasing the FIR spectrum in

the range o 983089983092983088983088 to 983089983094983088983088 cmminus1 corresponds to CndashH bondo CH2 and shows the broken chains Ag nanoparticles havegenerated new bonds in this range Decreasing the FIR

spectrum in the range o 983090983093983088983088 to 983091983095983088983088 cmminus1 shows theproduced polymerchains corresponds to OndashH stretching andCndashH stretching bonds

Te variation o transmittance () and re1047298ectance ()as a unction o wavelength or pure PVA polymer 1047297lmand samples 983089 to 983091 were recorded at room temperature and

7272019 pva films

httpslidepdfcomreaderfullpva-films 511

Journal o Nanomaterials 983093

500 1000 1500 2000 2500 3000 3500 40000

20

40

60

80

100

120

T

r a n s m i t t a n c e

Wavenumbers (cmminus1)

PVA

S1

S2

S3

F983145983143983157983154983141 983092 FIR spectrum o PVA pure 1047297lm and Ag nanoparticledoped in PVA polymer 1047297lms

200 400 600 800 1000 1200 1400 1600 1800 20000

01

02

03

04

05

06

07

0809

1

Wavelength (nm)

PVA

S1

S2

S3

Transmittance

Re1047298ectance

F983145983143983157983154983141 983093 Optical transmittance and re1047298ectance spectrum o sam-ples

are shown in Figure 983093 Pure PVA is a colorless polymerwithout any noticeable absorption in the visible range Tesharp increase observed in transmittance spectrum in therange o 983090983089983088 to 983090983092983096 nm is due to the presence o the PVApolymer bandgap [983089] Tis 1047297gure clearly indicates that aferadding nano-Ag in PVA polymer a valley at 983092983089983097 nm hasbeen created that its intensity continuously increasing withincreasing concentration o the dopant Tis new valley is

attributed to the ormation o charge transer complexes [983092983089]Te appearance o this valley in the visible region is dueto the surace plasmon resonance (SPR) nature o the Agnanoparticles embedded in PVA polymer dielectric medium

Aferdoping Ag nanoparticles in PVA polymer the re1047298ec-tion with increasing concentration o silver nanoparticlesdue to local 1047298uctuations charged particles declined

Te optical absorption coefficients o samples are evalu-ated rom the transmittance data using [983092983090]

1038389 = 1 ln 1048667

983131

(1 minus )22 + radic (1 minus )442 + 21048669

983133

(983089)

0 1 2 3 4 5 6 70

5

10

15

20

25

30

35

40

Photon energy (eV)

PVA

S1

S2

S3

A b s o r p t i o n

c o e

ffi c i e n t ( m m minus 1 )

F983145983143983157983154983141 983094 Optical absorption coefficient o 1047297lms

where and are the transmittance and re1047298ection respec-tively 1038389 is the absorption coefficient and is the thickness o the 1047297lms Figure 983094 presents the optical absorption coefficientsor undoped and nano-Ag doped PVA 1047297lms versus photonenergies Te absorption peak at 983090983097983093 eV or Ag nanoparticlesdoped in PVA polymer 1047297lms represents the characteristicsurace plasmon resonance dedicated to silver nanoparticlesTe presence o nanoparticles in the polymer 1047297lms could beconveniently ollowed by monitoringthe plasmon absorptionpeaks in the absorption spectrum Te larger absorptionpeak appeared in UV range is due to the energy gap o the PVA polymer which decreases owing to increasing theconcentration o Ag nanoparticles in the structure o the1047297lms Te position o the absorption edge was determinedby extrapolating the linear part o 1038389 versus ℎ] curves to zeroabsorption value [983092983089] Te band edge showed a decrease withincreasing concentration o Ag nanoparticles in PVA matrixTe absorption edge shifs towards higher wavelength indi-cating the decrease in the optical bandgap orthe doped 1047297lmsShifo the absorptionedgein the UVregionis due tochangesin the electron hole in the conduction and valence bands

Te most used method or estimation o the bandgapenergy rom optical measurement is the one proposed by auc and Grigorovici [983092983091] Te optical bandgap energy o samples was deduced rom the intercept o the extrapolated

linear part o the plot o (1038389)12 versus the photon energy with abscissa (Figure 983095) Tis ollows by the method o aucwhere

1038389 = 1048616 minus 10486171038389 (983090)

In this equation 1038389() is the absorption coefficient isthe photon energy is a actor that depends on transitionprobability and can be assumed to be constant within theoptical requency range and the index that is related tothe distribution o the density o states is an index whichassumes the values 983089983090 983091983090 983090 and 983091 depending on the natureo electronic transition aking = 2 which correspondsto indirectly allowed transition in pure PVA 1047297lm and nano-Ag doped PVA 1047297lms the bandgap energies o 1047297lms were

7272019 pva films

httpslidepdfcomreaderfullpva-films 611

983094 Journal o Nanomaterials

0 1 2 3 4 5 6 70

2

4

6

8

10

12

14

16

Photon energy (eV)

( 1038389 E ) 1 2

( m m minus 1 2 e V 1 2 )

PVA

S1

S2

S3

F983145983143983157983154983141 983095 (1038389)12 versus photon energy to illustrate auc method

calculated In an indirect gap a photon cannot be emittedbecause the electron must pass through an intermediatestate and transer momentum to the crystal lattice Teenergy gap o pure PVA sample is equal to 983092983097983094 eV andwith increasing the concentration o the Ag-nanoparticlesin the structure o 1047297lms bandgap energy is decreased Teextracted bandgap energy o sample are 983092983096983095 983092983096983092 and983092983095983096 eV or sample 983089ndash983091 respectively Te incorporation o the silver nanoparticles irrespective o their methodology o synthesis also affects the bandgap o the involved polymersystem Tis also con1047297rms the presence o the inorganic1047297llers inside the host [983089] Te variation o the calculated

values o optical bandgap re1047298ects the role o ormationo Ag-nanoparticles in modiying the electronic structureo the PVA matrix [983092983089 983092983092] Tese Ag-nanoparticles may be responsible or the ormation o localized electronicstates in the Highest Occupied Molecular Orbital-LowestUnoccupied Molecular Orbital (HOMO-LUMO) gap Teselocalized electronic states dominate the optical and electricalproperties vis-a-vis their role as trapping and recombinationcenters thus enhancing the low energy transitions leadingto the observed change in optical bandgap Te decrease inthe optical bandgap also re1047298ects the increase in the degreeo disorder in the 1047297lms which arises due to the change inpolymer structure [983092983092 983092983093]

Optical properties such as complex reractive index anddielectric constant or a certain range o wavelength betweenultraviolet and near inrared are important criteria or theselection o abricated 1047297lms or various applications Tereractive index is one o the undamental properties o a material because it is closely related to the electronicpolarizability o ions and the local 1047297eld inside the material [983096983097] Tus to urtherunderstand the interaction o Ag nanopar-ticles with PVA matrix optical properties such as complexreractive index and dielectric constant have been calculatedusing the undamental relations o photon transmittance ()re1047298ectance () and absorbance () Te complex reractiveindex is

= + that

is the real part and the extinction

0 1 2 3 4 5 6 713

14

15

16

17

18

19

2

Photon energy (eV)

R e f r a c t i v e i n d e x

PVA

S1

S2

S3

F983145983143983157983154983141 983096 Te reractive index o 1047297lms

coefficient

is the imaginary part Te reractive index

o

the 1047297lms was calculated using the ollowing equation [983092983094]

= 9830801 + 1 minus 983081 + radic 4(1 minus )2 minus 2 (983091)

in which = 110392510383894 Figures 983096 and 983097 show the photonenergy dependence o reractive index and the extinctioncoefficient or pure PVA and nano-Ag doped PVA 1047297lms Itcan be discerned rom Figure 983096 that the reractive index o nano-Ag doped PVA 1047297lms is lower than the reractive indexo pure PVA and it decreases with increasing concentrationo Ag nanoparticles in PVA matrix Tis property is inherentin all conductors and due to localized 1047298uctuation o charged

particles in medium Also decreasing the value o reractiveindex may be an indication o low density o 1047297lms whichleads to increasing the interatomic spacing [983092983093]Tisisduetoormation o intermolecular hydrogen bonding between Ag-nanoparticles and the adjacent OH groups Te dependenceo the reractive index on the 1047297lm density can be discussed by the well-known Clausius-Mossotti relation [983092983094]

Te extinction coefficient describes the properties o the material with respect to light o a given wavelength andindicates the absorption changes when the electromagneticwavepropagates through the material In Figure 983097 the extinc-tion coefficient o the doped samples have a peak at =295 eV which increases with increasing concentration o Ag nanoparticles in PVA dielectric medium Te extinctioncoefficient increases due to surace plasmon absorption indoped samples while the reractive index decreases in thisregion Tere is anomalous dispersion regions when 225 lt lt 2983097983093 eV and gt 485 eV as well as normal dispersionwhen 295 lt lt 345 eV or doped samples

Te complex dielectric unction is = 1103925 + 907317 where1103925 is the real part and 907317 is the imaginary part o dielectricconstant Te real and imaginary parts o dielectric constantare expressed as

1103925 = 2 minus 2907317 = 2 (983092)

7272019 pva films

httpslidepdfcomreaderfullpva-films 711

Journal o Nanomaterials 983095

0 1 2 3 4 5 6 70

1

2

3

4

5

6

7

8

Photon energy (eV)

E x t i n c t i o

n c o e

ffi c i e n t

PVA

S1

S2

S3

times10minus4

F983145983143983157983154983141 983097 Te extinction coefficient spectrum o 1047297lms

0 1 2 3 4 5 6 715

2

25

3

35

4

Photon energy (eV)

PVA

S1

S2

S3

1103925 r

F983145983143983157983154983141 983089983088 Real part o the dielectric constant o pure PVA and Agnanoparticle doped 1047297lms

Te real part o dielectric constant is related to the disper-sion In order to explain the dispersion it is necessary to takeinto account the actual motion o the electrons in the opticalmedium through which the light is traveling Te imaginary part represents the dissipative rate o electromagnetic wavepropagation in the medium Te real and imaginary partsdependences on photon energy o samples are shown in

Figures 983089983088 and 983089983089 respectively It can be concluded that 1103925is larger than 907317 because it mainly depends on 2 Withincreasing the amount o silver nanoparticles in PVA the realpart o dielectric constant is decreased It is due to decreaseo the dielectric property o 1047297lms because o Ag nanoparticlesmetal lattice in the host PVA polymer matrix Te normaldispersion is associated with an increase in Re() with andanomalous dispersion is associated with the reverse mecha-nism Normal dispersion is occurred everywhere expect inthe neighborhood o the resonance requency In this regionthe anomalous dispersion is appreciable Since a positiveimaginary part to 907317 represents dissipation o energy rom theelectromagnetic wave into the medium the regions where

907317

0 1 2 3 4 5 6 70

05

1

15

2

25

Photon energy (eV)

PVA

S1

S2

S3

times10minus3

1103925 i

F983145983143983157983154983141 983089983089 Imaginary part o the dielectric unction o 1047297lms

is large are called regions o resonant absorption [983092983095] Tepeak that appears in Figure 983089983089 at = 295 eV shows theplasmonic absorption

Te complex dielectric unction and complex opticalconductivity are introduced through Maxwellrsquos equationsTe interband transitions have threshold energy at the energy gap Tat is we expect the requency dependence o thereal part o the conductivity 1103925() due to an interbandtransition to exhibit a threshold or an allowed electronictransition [983092983096] In interband transition real 1103925 and imaginary 907317 components o optical conductivity are described as [983092983096ndash983093983088]

1103925 = 9073170907317 = 11039250 (983093)

where is the angular requency o electromagnetic wave and0 is the ree space dielectric constant Te real and imaginary parts o the optical conductivity dependence on the photonenergy are shown in Figures 983089983090 and 983089983091 respectively

Te real optical conductivity in bandgap energy regionafer doping the Ag-nanoparticles in PVA polymer decreasesIt can be due to the segregation effect [983092983089 983093983089] Te segregatedeffect is the dispersion o metallic particles restricted by thepresence o much larger polymeric particles Te observedeffect o Ag nanoparticles on the optical conductivity and

conduction behavior o PVA 1047297lms can be explained on thebasis o charge transer complex ormation involving PVAmolecules and the dopant When PVA polymer is mixedwith Ag nanoparticles as a result the 1047297ller is pushed intointerstitial space between the polymer particles and ormsa segregated network [983093983089] At higher dopant concentrationthere may be segregation o the dopant in the polymermatrix which decreases the conductivity Tus motion o charge carriers or localized 1047298uctuations o charged parti-cles in molecular aggregates impedes optical conductivityMoreover there is a weak peak at = 295 eV that can beseen only in the doped samples Tis new peak is attributedto the ormation o charge transer or the surace plasmon

7272019 pva films

httpslidepdfcomreaderfullpva-films 811

983096 Journal o Nanomaterials

0 1 2 3 4 5 6 70

02

04

06

08

1

12

14

16

18

2

Energy photon (eV)

PVA

S1

S2

S3

times10minus16

907317 r

( S m )

F983145983143983157983154983141 983089983090 Real part o the optical conductivity o pure PVA anddoped 1047297lms

0 1 2 3 4 5 6 70

05

1

15

2

25

3

35

Energy photon (eV)

PVA

S1

S2

S3

times10minus13

907317 i

( S m )

F983145983143983157983154983141 983089983091 Imaginary part o the optical conductivity o pure PVAand doped 1047297lms

silver nanoparticles Another result is that by increasingthe concentration o Ag nanoparticles in PVA matrix theimaginary part o optical conductivity decreases

A dielectric sample in an external electric 1047297eld acquiresa nonzero macroscopic dipole moment indicating that thedielectric is polarized under the in1047298uence o the 1047297eld Polar-ization o dielectric material achieves its equilibrium valuenot instantaneously but rather over a period o time [983093983090]Te dielectric relaxation time can be evaluated using

= infin minus 1103925907317 (983094)

Figure 983089983092 shows the dielectric relaxation time as a unc-tion o photon energy or pure PVA polymer and Agnanoparticle doped PVA 1047297lms Te valley at 983090983097983093 eV ordoped samples increases with increasing the concentrationo Ag nanoparticles in the structure o the 1047297lms In otherwords the relaxation time o dipole orientation decreases

2 25 3 35 4 45 5 550

02

04

06

08

1

12

14

16

18

2

Photon energy (eV)

R e

l a x a t

i o n t i m e

( s )

PVA

S1

S2

S3

times10minus12

F983145983143983157983154983141 983089983092 Relaxation time versus photon energy o 1047297lms

Tis is another reason or decreasing the dielectric unctionand increasing the conductivity o 1047297lms with increasing theconcentration o nanoparticles in their structure [983093983091]

Reractive index dispersion is a determinant actor inoptical materials It is a signi1047297cant actor in opticalcommuni-cation andin designingdevices orspectral dispersion[983091983093]Inthe normal dispersion region the reractive index dispersionhasbeen analyzed using thesingleoscillator model developedby theory o Wemple and DiDomenico [983093983092] Tey intro-duced a dispersion-energy parameter which connectsthe coordination number and the charge distribution withineach unit cell

is closely related to chemical bonding

Also they de1047297ned a single oscillator parameter 0 whichis proportional to the energy o oscillator In terms o thisdispersion energy and single oscillator energy 0 thereractive index at requency can be written as

12 minus 1 = 0

minus 10

(ℎ])2 (983095)

Te values o and 0 can be obtained rom the

intercept and slope o the linear part o (2 minus 1)minus1 plot versus

(ℎ]

)2 as is shown in Figure 983089983093 Also dispersion o reractive

index is controlled by the combined effects o and 0 Tecalculated values o the dispersion parameters (0 and )as well as the corresponding optical constant ( = 2) orthe pure PVA 1047297lm and samples 983089 to 983091 are listed in able 983089Te dispersion energy values decreases with increasing theconcentration o Ag nanoparticles in PVA 1047297lms because theanion strength o the dielectric medium has been declinedTereore the PVA polymer host is less willing to keep theelectrons in their outer layers Te single oscillator energy isan average energy gap as pointed out in many reerences [983093983088]Te 0 value o the 1047297lms is related empirically to the lowestindirect bandgap by 0 asymp 103 Tis relation is in goodagreement with the single oscillator model

7272019 pva films

httpslidepdfcomreaderfullpva-films 911

Journal o Nanomaterials 983097

10 105 11 115 12 125 1302

04

06

08

1

12

14

16

PVA

S1

S2

S3

(

n 2

minus

1 ) minus 1

E2 (eV2)

F983145983143983157983154983141 983089983093Plot o (2minus1) versus squared photon energy o pure PVAand doping samples

983137983138983148983141 983089 Dispersion parameters o 1047297lmsSamples 0

PVA 983089983093983094 983090983092983092 983093983089983097 983095983092983097

S983089 983089983092983096 983090983089983097 983093983088983092 983094983088983091

S983090 983089983091983095 983089983096983097 983092983097983095 983092983092983094

S983091 983089983089983097 983089983092983090 983092983096983095 983090983088983093

4 Conclusions

Preparation o silver nanoparticles by laser ablation methodat different 1047298uencies o laser pulse in pure water is investi-gated Te EM analysis revealed that generated nanoparti-

cles in this experimental condition are almost spherical andtheir average size was 983094ndash983089983090 nm and with increasing the laserpulse 1047298uence the size o nanoparticles is decreased Te X-ray diffraction spectrum reveals that the number o crystal-lographic planes at certain angles is increased afer doping Agnanoparticles in the structure o PVA FIR spectrum peakscorrespond to molecular vibrations and chemical bondsindicate the presence o silver in the PVA polymer structureTe optical bandgap energy o the samples is decreasedwith increasing the concentrations o silver nanoparticlesReractive index and dielectric constant are decreased withincreasing the concentration o Ag nanoparticles Increaseo dopant concentration resulted in a decrease in real part

o the optical conductivity because o segregation effectTe reractive index and consequently the related dispersionparameters o PVA and doped PVA have been determinedand explained using the Wemple-DiDomenico model

References

[983089] A Nimrodh Ananth and S Umapathy ldquoOn the optical andthermal properties o in situex situ reduced Ag NPrsquosPVAcomposites and its role as a simple SPR-based protein sensorrdquo Applied Nanoscience vol 983089 no 983090 pp 983096983095ndash983097983094 983090983088983089983089

[983090] G Nesher G Marom and D Avnir ldquoMetal-polymer compos-ites synthesis and characterization o polyaniline and other

polymer at Silver compositionsrdquo Chemistry of Materialsvol983090983088no 983089983091 pp 983092983092983090983093ndash983092983092983091983090 983090983088983088983096

[983091] P-H Wang Y-Z Wu andQ-R ZhuldquoPolymermetal compositeparticles polymer core and metal shellrdquo Journal of MaterialsScience Letters vol 983090983089 no 983090983091 pp 983089983096983090983093ndash983089983096983090983096 983090983088983088983090

[983092] S Clemenson P Alcouffe L David and E Espuche ldquoStructureand morphology o membranes prepared rom polyvinyl alco-hol and silver nitrate in1047298uence o the annealing treatment ando the 1047297lm thicknessrdquo Desalination vol 983090983088983088 no 983089-983091 pp 983092983091983095ndash983092983091983097 983090983088983088983094

[983093] K Akamatsu S akei M Mizuhata et al ldquoPreparation andcharacterization o polymer thin 1047297lms containing silver andsilver sul1047297de nanoparticlesrdquo Tin Solid Films vol 983091983093983097 no 983089 pp983093983093ndash983094983088 983090983088983088983088

[983094] R Zeng M Z Rong M Q Zhang H C Liang and H MZeng ldquoLaser ablation o polymer-based silver nanocompositesrdquo Applied Surface Science vol 983089983096983095 no 983091-983092 pp 983090983091983097ndash983090983092983095 983090983088983088983090

[983095] S Mahendia A K omar and S Kumar ldquoElectrical conduc-tivity and dielectric spectroscopic studies o PVA-Ag nanocom-posite 1047297lmsrdquo Journal of Alloys and Compounds vol 983093983088983096 no 983090pp 983092983088983094ndash983092983089983089 983090983088983089983088

[983096] N Singh and P K Khanna ldquoIn situ synthesis o silver nano-particles in polymethylmethacrylaterdquo Materials Chemistry and Physics vol 983089983088983092 no 983090-983091 pp 983091983094983095ndash983091983095983090 983090983088983088983095

[983097] P K Khanna R Gokhale V V V S Subbarao A K Vish-wanath B K Das and C V V Satyanarayana ldquoPVA stabilizedgold nanoparticles by use o unexplored albeit conventionalreducing agentrdquo Materials Chemistry and Physics vol 983097983090 no983089 pp 983090983090983097ndash983090983091983091 983090983088983088983093

[983089983088] K Akamatsu S akei M Mizuhata et al ldquoPreparation andcharacterization o polymer thin 1047297lms containing silver andsilver sul1047297de nanoparticlesrdquo Tin Solid Films vol 983091983093983097 no 983089 pp983093983093ndash983094983088 983090983088983088983088

[983089983089] I Hussain M Brust A J Papworth and A I Cooper

ldquoPreparationo acrylate-stabilized goldand silver hydrosols andgold-polymer composite 1047297lmsrdquo Langmuir vol 983089983097 no 983089983089 pp983092983096983091983089ndash983092983096983091983093 983090983088983088983091

[983089983090] S A Zavyalov A N Pivkina and J Schoonman ldquoFormationand characterization o metal-polymer nanostructured com-positesrdquo Solid State Ionics vol 983089983092983095 no 983091-983092 pp 983092983089983093ndash983092983089983097 983090983088983088983090

[983089983091] J Lee D Bhattacharyya A J Easteal and J B Metson ldquoProp-erties o nano-ZnOpoly(vinyl alcohol)poly(ethylene oxide)composite thin 1047297lmsrdquo Current Applied Physics vol 983096 no 983089 pp983092983090ndash983092983095 983090983088983088983096

[983089983092] Z Zhong D Wang Y Cui M W Bockrath and C H LieberldquoNanowire crossbar arrays as address decoders or integratednanosystemsrdquo Science vol 983091983088983090 no 983093983094983092983097 pp 983089983091983095983095ndash983089983091983095983097 983090983088983088983091

[983089983093] D S Hopkins D Pekker P M Goldbart and A Bezryadin

ldquoQuantum intererence device made by DNA templating o superconducting nanowiresrdquo Science vol 983091983088983096 no 983093983095983090983097 pp983089983095983094983090ndash983089983095983094983093 983090983088983088983093

[983089983094] S Clemenson D Leonard D Sage L David and E EspucheldquoMetal nanocomposite 1047297lms prepared in Situ rom PVA andsilver nitrate Study o the nanostructuration process andmorphology as a unction o the in Situ routesrdquo Journal of Polymer Science A vol 983092983094 no 983094 pp 983090983088983094983090ndash983090983088983095983089 983090983088983088983096

[983089983095] M K emgire and S S Joshi ldquoOptical and structural studies o silver nanoparticlesrdquo Radiation Physics and Chemistry vol 983095983089no 983093 pp 983089983088983091983097ndash983089983088983092983092 983090983088983088983092

[983089983096] M Zheng M Gu Y Jin and G Jin ldquoOptical properties o silver-dispersed PVP thin 1047297lmrdquo Materials Research Bulletin vol 983091983094no 983093-983094 pp 983096983093983091ndash983096983093983097 983090983088983088983089

7272019 pva films

httpslidepdfcomreaderfullpva-films 1011

983089983088 Journal o Nanomaterials

[983089983097] O L A Monti J Fourkas and D J Nesbitt ldquoDiffraction-limited photogeneration and characterization o silver nanopar-ticlesrdquo Journal of Physical Chemistry B vol 983089983088983096 no 983093 pp 983089983094983088983092ndash983089983094983089983090 983090983088983088983092

[983090983088] K L Kelly E Coronado L L Zhao and G C Schatz ldquoTeopti-cal properties o metal nanoparticles the in1047298uence o sizeshape and dielectric environmentrdquo Journal of Physical Che-

mistry B vol 983089983088983095 no 983091 pp 983094983094983096ndash983094983095983095 983090983088983088983091

[983090983089] H Weickmann J C iller R Tomann and R MulhauptldquoMetallized organoclays as new intermediates or aqueous nan-ohybrid dispersions nanohybrid catalysts and antimicrobialpolymer hybrid nanocompositesrdquo Macromolecular Materialsand Engineering vol 983090983097983088 no 983097 pp 983096983095983093ndash983096983096983091 983090983088983088983093

[983090983090] U Keirbeg and M Vollmer Optical Properties of Metal Clusters vol 983090983093 o Springer Series in Material Science 983089983097983097983093

[983090983091] S Chen and J M Sommers ldquoAlkanethiolate-protected coppernanoparticles spectroscopy electrochemistry and solid-statemorphological evolutionrdquo Journal of Physical Chemistry B vol983089983088983093 no 983091983095 pp 983096983096983089983094ndash983096983096983090983088 983090983088983088983089

[983090983092] A A Scalisi G Compagnini L DrsquoUrso and O Puglisi ldquoNon-linearopticalactivity in Ag-SiO

2 nanocomposite thin 1047297lms with

different silver concentrationrdquo Applied Surface Science vol 983090983090983094no 983089ndash983091 pp 983090983091983095ndash983090983092983089 983090983088983088983092

[983090983093] G Yang W Wang Y Zhou H Lu G Yang and Z Chen ldquoLin-ear and nonlinear optical properties o Ag nanoclusterBaiO3

composite 1047297lmsrdquo Applied Physics Letters vol 983096983089 no 983090983089 pp983091983097983094983097ndash983091983097983095983089 983090983088983088983090

[983090983094] H B Liao R F Xiao H Wang K S Wong and G K L WongldquoLarge third-order optical nonlinearity in AuiO2 composite1047297lms measured on a emtosecond time scalerdquo Applied PhysicsLetters vol 983095983090 no 983089983093 pp 983089983096983089983095ndash983089983096983089983097 983089983097983097983096

[983090983095] A K Sarychev D J Bergman and Y Yagil ldquoTeory o theoptical and microwave properties o metal-dielectric 1047297lmsrdquoPhysical Review B vol 983093983089 no 983096 pp 983093983091983094983094ndash983093983091983096983093 983089983097983097983093

[983090983096] G Mie ldquoBeitrage zur Optik truber Medien speziell kolloidalerMetallosungenrdquo Annalen der Physik vol 983091983091983088 pp 983091983095983095ndash983092983092983093 983089983097983088983096

[983090983097] R Gans ldquoUber die Form ultramikroskopischer Silberteilchenrdquo Annalen der Physik vol 983091983093983090 no 983089983088 pp 983090983095983088ndash983090983096983092 983089983097983089983093

[983091983088] S Link and M A El-Sayed ldquoSpectral properties and relaxationdynamics o surace plasmon electronic oscillations in gold andsilver nanodots and nanorodsrdquo Journal of Physical Chemistry B vol 983089983088983091 no 983092983088 pp 983096983092983089983088ndash983096983092983090983094 983089983097983097983097

[983091983089] G Fussell J Tomas J Scanlon A Lowman and M Mar-colongo ldquoTe effect o protein-ree versus protein-containingmedium on the mechanical properties and uptake o ions o PVAPVP hydrogelsrdquo Journalof BiomaterialsScience vol983089983094 no983092 pp 983092983096983097ndash983093983088983091 983090983088983088983093

[983091983090] suji Mizuki S Ozono and M suji ldquoLaser-induced sil-

ver nanocrystal ormation in polyvinylpyrrolidone solutionsrdquo Journal of Photochemistry and Photobiology A vol 983090983088983094 no 983090-983091pp 983089983091983092ndash983089983091983097 983090983088983088983097

[983091983091] J-P Sylvestre S Poulin A V Kabashin E Sacher M Meunierand J H Luong ldquoSurace chemistry o gold nanoparticlesproduced by laser ablation in aqueous mediardquo Journal of Physical Chemistry B vol 983089983088983096 no 983092983091 pp 983089983094983096983094983092ndash983089983094983096983094983097 983090983088983088983092

[983091983092] A Gautam and S Ram ldquoPreparation and thermomechanicalproperties o Ag-PVA nanocomposite 1047297lmsrdquo Materials Chem-istry and Physics vol 983089983089983097 no 983089-983090 pp 983090983094983094ndash983090983095983089 983090983088983089983088

[983091983093] I Saini J Rozra N Chandak S Aggarwal P K Sharmaand A Sharma ldquoailoring o electrical optical and structuralproperties o PVA by addition o Ag nanoparticlesrdquo MaterChem Phys vol 983089983091983097 pp 983096983088983090ndash983096983089983088 983090983088983089983091

[983091983094] S Mahendia A K omar and S Kumar ldquoNano-Ag dopinginduced changes in optical and electrical behaviour o PVA1047297lmsrdquo Materials Science and Engineering B vol 983089983095983094 no 983095 pp983093983091983088ndash983093983091983092 983090983088983089983089

[983091983095] M Abdelaziz and E M Abdelrazek ldquoEffect o dopant mixtureon structural optical and electron spin resonance properties o polyvinyl alcoholrdquo Physica B vol 983091983097983088 no 983089-983090 pp 983089ndash983097 983090983088983088983095

[983091983096] B Suo X Su J Wu D Chen A Wang and Z Guo ldquoPoly (vinyl alcohol) thin 1047297lm 1047297lled with CdSe-ZnS quantum dotsabrication characterization and optical propertiesrdquo MaterialsChemistry and Physics vol 983089983089983097 no 983089-983090 pp 983090983091983095ndash983090983092983090 983090983088983089983088

[983091983097] B Karthikeyan ldquoSpectroscopic studies on Ag-polyvinyl alcoholnanocomposite 1047297lmsrdquo Physica B vol 983091983094983092 no 983089ndash983092 pp 983091983090983096ndash983091983091983090983090983088983088983093

[983092983088] A S Kutsenko and V M Granchak ldquoPhotochemical synthesiso silver nanoparticles in polyvinyl alcohol matricesrdquo Teoreti-cal and Experimental Chemistry vol 983092983093no 983093 pp 983091983089983091ndash983091983089983096983090983088983088983097

[983092983089] C U Devi A K Sharma and V V R N Rao ldquoElectrical andoptical properties o pure and silver nitrate-doped polyvinylalcohol 1047297lmsrdquo Materials Letters vol 983093983094 no 983091 pp 983089983094983095ndash983089983095983092 983090983088983088983090

[983092983090] B G Streetman Solid State Electronic Devices Prentice HallNew Jersey NJ USA 983091rd edition 983089983097983097983088

[983092983091] J auc and R Grigorovici ldquoOptical properties and electronicstructure o amorphous germaniumrdquo Physica Status Solidi (B) vol 983089983093 no 983090 pp 983094983090983095ndash983094983091983095 983089983097983094983094

[983092983092] J Rozra I Saini A Sharma et al ldquoCu nanoparticles inducedstructural optical and electrical modi1047297cation in PVArdquo Materi-als Chemistry and Physics vol 983089983091983092 no 983090-983091 pp 983089983089983090983089ndash983089983089983090983094 983090983088983089983090

[983092983093] M Abdelaziz ldquoCerium (III) doping effects on optical andthermal properties o PVA 1047297lmsrdquo Physica B vol 983092983088983094 no 983094-983095pp 983089983091983088983088ndash983089983091983088983095 983090983088983089983089

[983092983094] C Kittle Introduction to Solid State Physics vol 983092983088983093 John Wiley amp Sons New York NY USA 983089983097983095983089

[983092983095] J D Jackson Classical Electrodynamics John Wiley amp Sons 983091rdedition 983089983097983097983097

[983092983096] M S Dresselhaus Solid State Physics Part II Optical Propertiesof Solids vol 983094 983090983088983088983089

[983092983097] J N Hodgson Optical Absorption and Dispersion in Solids Chapman amp Hall London UK 983089983097983095983089

[983093983088] Y Caglar S Ilican and M Caglar ldquoSingle-oscillator modeland determination o optical constants o spray pyrolyzedamorphous SnO2 thin 1047297lmsrdquo European Physical Journal B vol983093983096 no 983091 pp 983090983093983089ndash983090983093983094 983090983088983088983095

[983093983089] Y Seok Kim Electrical Conductivity of Segregated NetworkPolymer Nanoposites vol 983089983091983095 983090983088983088983095

[983093983090] Y Feldman A Puzenko and Y Ryabov ldquoDielectric relaxationphenomena in complex materialsrdquo in Advances in Chemical

Physics vol 983089983091983091 pp 983089ndash983089983090983093 Department o Applied Physics TeHebrew University o Jerusalem Jerusalem Israel 983090983088983088983094

[983093983091] S Mahendia A K omar R P Chahal P Goyal and S KumarldquoOptical and structural properties o poly(vinyl alcohol) 1047297lmsembedded with citrate-stabilized gold nanoparticlesrdquo Journal of Physics D vol 983092983092 no 983090983088 Article ID 983090983088983093983089983088983093 983090983088983089983089

[983093983092] S H Wemple and M DiDomenico ldquoBehavior o the electronicdielectric constant in covalent and ionic materialsrdquo Physical Review B vol 983091 no 983092 pp 983089983091983091983096ndash983089983091983093983089 983089983097983095983089

7272019 pva films

httpslidepdfcomreaderfullpva-films 1111

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2013Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The ScientifcWorld Journal

Impact Factor 1730

28 Days Fast Track Peer Review

All Subject Areas of Science

Submit at httpwwwtswjcom

7272019 pva films

httpslidepdfcomreaderfullpva-films 411

983092 Journal o Nanomaterials

10 20 30 40 50 60 70 80 90

0

500

1000

1500

2000

I n t e n s i t y

( a u )

Ag nanoparticles

PVA polymer

S1

2 (∘)

minus500

(a) S983089 (983089983093Jcm2)

10 20 30 40 50 60 70 80 90

0

500

1000

1500

2000

I n t e n s i t y

( a u )

Ag nanoparticles

PVA polymer

S2

2 (∘)

minus500

(b) S983090 (983090 Jcm2)

10 20 30 40 50 60 70 80 90

0

500

1000

1500

2000

I n t e n s i t y

( a u )

Ag nanoparticles

PVA polymer

S3

2 (∘)

minus500

(c) S983091 (983091 Jcm2)

F983145983143983157983154983141 983091 X-ray diffraction patterns o Ag nanoparticles PVA polymer and Ag nanoparticle doped PVA 1047297lms (a) S983089 (b) S983090 and (c) S983091

o PVA chains afer Ag doping Decreasing the intensity o peaks in FIR spectrum con1047297rms that afer doping numbero PVA chains are increased in the structure o the 1047297lmsSame results have been observed by Mahendia et al andGautam and Ram [983095 983091983092] For 2907317 gt 20∘ increasing theintensity o XRD peaks is due to increasing the number o crystallographic planes at certain angles

Te Fourier transorm inrared spectroscopy (FIR)

spectra o pure PVA and doped 1047297lms are shown in Figure 983092All spectra exhibit the characteristic absorption bands o purePVA which are 983091983093983096983088 983090983097983095983092 983089983095983092983088 983089983093983095983088 983089983092983094983088 and 983096983092983093 cmminus1

[983091983095 983091983096] It can be noticed that these treatments cause someobservable changes in the spectral eatures o the samples

in the range 983089983089983088983088ndash983093983088983088 cmminus1 (1047297ngerprint region) apart romnew absorption bands and slight changes in the intensitieso some absorption bands Te new bands may be correlatedlikewise with deects induced by the charge transer reactionbetween the polymer chain and the dopant Te vibrational

peaks at 983091983093983096983088 983090983097983095983092 983089983095983092983088 983089983092983094983088 and 983096983092983093 cmminus1 are assignedto OndashH stretching CndashH stretching C=O stretching CndashH

bend o CH2 and CH rocking o PVA respectively [983091983097983092983088] Further the vibrational peaks ound in the range 983089983089983091983088ndash

983094983093983088 cmminus1 may be attributed to AgndashO which indicate thatsilver nanoparticles doped in the PVA polymer matrix [983091983095]Te experimental data given in Figure 983092 indicate an increasein the vibrations o OndashH CndashH and C=O groups in the PVAmatrix afer adding Ag nanoparticles directly in the PVA1047297lm Such changes in OndashH CndashH and C=O vibrations have

been observed in other report [983092983088] Afer doping Ag somepolymers chains have been broken and some other chainshave been ormed instead Increasing the FIR spectrum in

the range o 983089983092983088983088 to 983089983094983088983088 cmminus1 corresponds to CndashH bondo CH2 and shows the broken chains Ag nanoparticles havegenerated new bonds in this range Decreasing the FIR

spectrum in the range o 983090983093983088983088 to 983091983095983088983088 cmminus1 shows theproduced polymerchains corresponds to OndashH stretching andCndashH stretching bonds

Te variation o transmittance () and re1047298ectance ()as a unction o wavelength or pure PVA polymer 1047297lmand samples 983089 to 983091 were recorded at room temperature and

7272019 pva films

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Journal o Nanomaterials 983093

500 1000 1500 2000 2500 3000 3500 40000

20

40

60

80

100

120

T

r a n s m i t t a n c e

Wavenumbers (cmminus1)

PVA

S1

S2

S3

F983145983143983157983154983141 983092 FIR spectrum o PVA pure 1047297lm and Ag nanoparticledoped in PVA polymer 1047297lms

200 400 600 800 1000 1200 1400 1600 1800 20000

01

02

03

04

05

06

07

0809

1

Wavelength (nm)

PVA

S1

S2

S3

Transmittance

Re1047298ectance

F983145983143983157983154983141 983093 Optical transmittance and re1047298ectance spectrum o sam-ples

are shown in Figure 983093 Pure PVA is a colorless polymerwithout any noticeable absorption in the visible range Tesharp increase observed in transmittance spectrum in therange o 983090983089983088 to 983090983092983096 nm is due to the presence o the PVApolymer bandgap [983089] Tis 1047297gure clearly indicates that aferadding nano-Ag in PVA polymer a valley at 983092983089983097 nm hasbeen created that its intensity continuously increasing withincreasing concentration o the dopant Tis new valley is

attributed to the ormation o charge transer complexes [983092983089]Te appearance o this valley in the visible region is dueto the surace plasmon resonance (SPR) nature o the Agnanoparticles embedded in PVA polymer dielectric medium

Aferdoping Ag nanoparticles in PVA polymer the re1047298ec-tion with increasing concentration o silver nanoparticlesdue to local 1047298uctuations charged particles declined

Te optical absorption coefficients o samples are evalu-ated rom the transmittance data using [983092983090]

1038389 = 1 ln 1048667

983131

(1 minus )22 + radic (1 minus )442 + 21048669

983133

(983089)

0 1 2 3 4 5 6 70

5

10

15

20

25

30

35

40

Photon energy (eV)

PVA

S1

S2

S3

A b s o r p t i o n

c o e

ffi c i e n t ( m m minus 1 )

F983145983143983157983154983141 983094 Optical absorption coefficient o 1047297lms

where and are the transmittance and re1047298ection respec-tively 1038389 is the absorption coefficient and is the thickness o the 1047297lms Figure 983094 presents the optical absorption coefficientsor undoped and nano-Ag doped PVA 1047297lms versus photonenergies Te absorption peak at 983090983097983093 eV or Ag nanoparticlesdoped in PVA polymer 1047297lms represents the characteristicsurace plasmon resonance dedicated to silver nanoparticlesTe presence o nanoparticles in the polymer 1047297lms could beconveniently ollowed by monitoringthe plasmon absorptionpeaks in the absorption spectrum Te larger absorptionpeak appeared in UV range is due to the energy gap o the PVA polymer which decreases owing to increasing theconcentration o Ag nanoparticles in the structure o the1047297lms Te position o the absorption edge was determinedby extrapolating the linear part o 1038389 versus ℎ] curves to zeroabsorption value [983092983089] Te band edge showed a decrease withincreasing concentration o Ag nanoparticles in PVA matrixTe absorption edge shifs towards higher wavelength indi-cating the decrease in the optical bandgap orthe doped 1047297lmsShifo the absorptionedgein the UVregionis due tochangesin the electron hole in the conduction and valence bands

Te most used method or estimation o the bandgapenergy rom optical measurement is the one proposed by auc and Grigorovici [983092983091] Te optical bandgap energy o samples was deduced rom the intercept o the extrapolated

linear part o the plot o (1038389)12 versus the photon energy with abscissa (Figure 983095) Tis ollows by the method o aucwhere

1038389 = 1048616 minus 10486171038389 (983090)

In this equation 1038389() is the absorption coefficient isthe photon energy is a actor that depends on transitionprobability and can be assumed to be constant within theoptical requency range and the index that is related tothe distribution o the density o states is an index whichassumes the values 983089983090 983091983090 983090 and 983091 depending on the natureo electronic transition aking = 2 which correspondsto indirectly allowed transition in pure PVA 1047297lm and nano-Ag doped PVA 1047297lms the bandgap energies o 1047297lms were

7272019 pva films

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983094 Journal o Nanomaterials

0 1 2 3 4 5 6 70

2

4

6

8

10

12

14

16

Photon energy (eV)

( 1038389 E ) 1 2

( m m minus 1 2 e V 1 2 )

PVA

S1

S2

S3

F983145983143983157983154983141 983095 (1038389)12 versus photon energy to illustrate auc method

calculated In an indirect gap a photon cannot be emittedbecause the electron must pass through an intermediatestate and transer momentum to the crystal lattice Teenergy gap o pure PVA sample is equal to 983092983097983094 eV andwith increasing the concentration o the Ag-nanoparticlesin the structure o 1047297lms bandgap energy is decreased Teextracted bandgap energy o sample are 983092983096983095 983092983096983092 and983092983095983096 eV or sample 983089ndash983091 respectively Te incorporation o the silver nanoparticles irrespective o their methodology o synthesis also affects the bandgap o the involved polymersystem Tis also con1047297rms the presence o the inorganic1047297llers inside the host [983089] Te variation o the calculated

values o optical bandgap re1047298ects the role o ormationo Ag-nanoparticles in modiying the electronic structureo the PVA matrix [983092983089 983092983092] Tese Ag-nanoparticles may be responsible or the ormation o localized electronicstates in the Highest Occupied Molecular Orbital-LowestUnoccupied Molecular Orbital (HOMO-LUMO) gap Teselocalized electronic states dominate the optical and electricalproperties vis-a-vis their role as trapping and recombinationcenters thus enhancing the low energy transitions leadingto the observed change in optical bandgap Te decrease inthe optical bandgap also re1047298ects the increase in the degreeo disorder in the 1047297lms which arises due to the change inpolymer structure [983092983092 983092983093]

Optical properties such as complex reractive index anddielectric constant or a certain range o wavelength betweenultraviolet and near inrared are important criteria or theselection o abricated 1047297lms or various applications Tereractive index is one o the undamental properties o a material because it is closely related to the electronicpolarizability o ions and the local 1047297eld inside the material [983096983097] Tus to urtherunderstand the interaction o Ag nanopar-ticles with PVA matrix optical properties such as complexreractive index and dielectric constant have been calculatedusing the undamental relations o photon transmittance ()re1047298ectance () and absorbance () Te complex reractiveindex is

= + that

is the real part and the extinction

0 1 2 3 4 5 6 713

14

15

16

17

18

19

2

Photon energy (eV)

R e f r a c t i v e i n d e x

PVA

S1

S2

S3

F983145983143983157983154983141 983096 Te reractive index o 1047297lms

coefficient

is the imaginary part Te reractive index

o

the 1047297lms was calculated using the ollowing equation [983092983094]

= 9830801 + 1 minus 983081 + radic 4(1 minus )2 minus 2 (983091)

in which = 110392510383894 Figures 983096 and 983097 show the photonenergy dependence o reractive index and the extinctioncoefficient or pure PVA and nano-Ag doped PVA 1047297lms Itcan be discerned rom Figure 983096 that the reractive index o nano-Ag doped PVA 1047297lms is lower than the reractive indexo pure PVA and it decreases with increasing concentrationo Ag nanoparticles in PVA matrix Tis property is inherentin all conductors and due to localized 1047298uctuation o charged

particles in medium Also decreasing the value o reractiveindex may be an indication o low density o 1047297lms whichleads to increasing the interatomic spacing [983092983093]Tisisduetoormation o intermolecular hydrogen bonding between Ag-nanoparticles and the adjacent OH groups Te dependenceo the reractive index on the 1047297lm density can be discussed by the well-known Clausius-Mossotti relation [983092983094]

Te extinction coefficient describes the properties o the material with respect to light o a given wavelength andindicates the absorption changes when the electromagneticwavepropagates through the material In Figure 983097 the extinc-tion coefficient o the doped samples have a peak at =295 eV which increases with increasing concentration o Ag nanoparticles in PVA dielectric medium Te extinctioncoefficient increases due to surace plasmon absorption indoped samples while the reractive index decreases in thisregion Tere is anomalous dispersion regions when 225 lt lt 2983097983093 eV and gt 485 eV as well as normal dispersionwhen 295 lt lt 345 eV or doped samples

Te complex dielectric unction is = 1103925 + 907317 where1103925 is the real part and 907317 is the imaginary part o dielectricconstant Te real and imaginary parts o dielectric constantare expressed as

1103925 = 2 minus 2907317 = 2 (983092)

7272019 pva films

httpslidepdfcomreaderfullpva-films 711

Journal o Nanomaterials 983095

0 1 2 3 4 5 6 70

1

2

3

4

5

6

7

8

Photon energy (eV)

E x t i n c t i o

n c o e

ffi c i e n t

PVA

S1

S2

S3

times10minus4

F983145983143983157983154983141 983097 Te extinction coefficient spectrum o 1047297lms

0 1 2 3 4 5 6 715

2

25

3

35

4

Photon energy (eV)

PVA

S1

S2

S3

1103925 r

F983145983143983157983154983141 983089983088 Real part o the dielectric constant o pure PVA and Agnanoparticle doped 1047297lms

Te real part o dielectric constant is related to the disper-sion In order to explain the dispersion it is necessary to takeinto account the actual motion o the electrons in the opticalmedium through which the light is traveling Te imaginary part represents the dissipative rate o electromagnetic wavepropagation in the medium Te real and imaginary partsdependences on photon energy o samples are shown in

Figures 983089983088 and 983089983089 respectively It can be concluded that 1103925is larger than 907317 because it mainly depends on 2 Withincreasing the amount o silver nanoparticles in PVA the realpart o dielectric constant is decreased It is due to decreaseo the dielectric property o 1047297lms because o Ag nanoparticlesmetal lattice in the host PVA polymer matrix Te normaldispersion is associated with an increase in Re() with andanomalous dispersion is associated with the reverse mecha-nism Normal dispersion is occurred everywhere expect inthe neighborhood o the resonance requency In this regionthe anomalous dispersion is appreciable Since a positiveimaginary part to 907317 represents dissipation o energy rom theelectromagnetic wave into the medium the regions where

907317

0 1 2 3 4 5 6 70

05

1

15

2

25

Photon energy (eV)

PVA

S1

S2

S3

times10minus3

1103925 i

F983145983143983157983154983141 983089983089 Imaginary part o the dielectric unction o 1047297lms

is large are called regions o resonant absorption [983092983095] Tepeak that appears in Figure 983089983089 at = 295 eV shows theplasmonic absorption

Te complex dielectric unction and complex opticalconductivity are introduced through Maxwellrsquos equationsTe interband transitions have threshold energy at the energy gap Tat is we expect the requency dependence o thereal part o the conductivity 1103925() due to an interbandtransition to exhibit a threshold or an allowed electronictransition [983092983096] In interband transition real 1103925 and imaginary 907317 components o optical conductivity are described as [983092983096ndash983093983088]

1103925 = 9073170907317 = 11039250 (983093)

where is the angular requency o electromagnetic wave and0 is the ree space dielectric constant Te real and imaginary parts o the optical conductivity dependence on the photonenergy are shown in Figures 983089983090 and 983089983091 respectively

Te real optical conductivity in bandgap energy regionafer doping the Ag-nanoparticles in PVA polymer decreasesIt can be due to the segregation effect [983092983089 983093983089] Te segregatedeffect is the dispersion o metallic particles restricted by thepresence o much larger polymeric particles Te observedeffect o Ag nanoparticles on the optical conductivity and

conduction behavior o PVA 1047297lms can be explained on thebasis o charge transer complex ormation involving PVAmolecules and the dopant When PVA polymer is mixedwith Ag nanoparticles as a result the 1047297ller is pushed intointerstitial space between the polymer particles and ormsa segregated network [983093983089] At higher dopant concentrationthere may be segregation o the dopant in the polymermatrix which decreases the conductivity Tus motion o charge carriers or localized 1047298uctuations o charged parti-cles in molecular aggregates impedes optical conductivityMoreover there is a weak peak at = 295 eV that can beseen only in the doped samples Tis new peak is attributedto the ormation o charge transer or the surace plasmon

7272019 pva films

httpslidepdfcomreaderfullpva-films 811

983096 Journal o Nanomaterials

0 1 2 3 4 5 6 70

02

04

06

08

1

12

14

16

18

2

Energy photon (eV)

PVA

S1

S2

S3

times10minus16

907317 r

( S m )

F983145983143983157983154983141 983089983090 Real part o the optical conductivity o pure PVA anddoped 1047297lms

0 1 2 3 4 5 6 70

05

1

15

2

25

3

35

Energy photon (eV)

PVA

S1

S2

S3

times10minus13

907317 i

( S m )

F983145983143983157983154983141 983089983091 Imaginary part o the optical conductivity o pure PVAand doped 1047297lms

silver nanoparticles Another result is that by increasingthe concentration o Ag nanoparticles in PVA matrix theimaginary part o optical conductivity decreases

A dielectric sample in an external electric 1047297eld acquiresa nonzero macroscopic dipole moment indicating that thedielectric is polarized under the in1047298uence o the 1047297eld Polar-ization o dielectric material achieves its equilibrium valuenot instantaneously but rather over a period o time [983093983090]Te dielectric relaxation time can be evaluated using

= infin minus 1103925907317 (983094)

Figure 983089983092 shows the dielectric relaxation time as a unc-tion o photon energy or pure PVA polymer and Agnanoparticle doped PVA 1047297lms Te valley at 983090983097983093 eV ordoped samples increases with increasing the concentrationo Ag nanoparticles in the structure o the 1047297lms In otherwords the relaxation time o dipole orientation decreases

2 25 3 35 4 45 5 550

02

04

06

08

1

12

14

16

18

2

Photon energy (eV)

R e

l a x a t

i o n t i m e

( s )

PVA

S1

S2

S3

times10minus12

F983145983143983157983154983141 983089983092 Relaxation time versus photon energy o 1047297lms

Tis is another reason or decreasing the dielectric unctionand increasing the conductivity o 1047297lms with increasing theconcentration o nanoparticles in their structure [983093983091]

Reractive index dispersion is a determinant actor inoptical materials It is a signi1047297cant actor in opticalcommuni-cation andin designingdevices orspectral dispersion[983091983093]Inthe normal dispersion region the reractive index dispersionhasbeen analyzed using thesingleoscillator model developedby theory o Wemple and DiDomenico [983093983092] Tey intro-duced a dispersion-energy parameter which connectsthe coordination number and the charge distribution withineach unit cell

is closely related to chemical bonding

Also they de1047297ned a single oscillator parameter 0 whichis proportional to the energy o oscillator In terms o thisdispersion energy and single oscillator energy 0 thereractive index at requency can be written as

12 minus 1 = 0

minus 10

(ℎ])2 (983095)

Te values o and 0 can be obtained rom the

intercept and slope o the linear part o (2 minus 1)minus1 plot versus

(ℎ]

)2 as is shown in Figure 983089983093 Also dispersion o reractive

index is controlled by the combined effects o and 0 Tecalculated values o the dispersion parameters (0 and )as well as the corresponding optical constant ( = 2) orthe pure PVA 1047297lm and samples 983089 to 983091 are listed in able 983089Te dispersion energy values decreases with increasing theconcentration o Ag nanoparticles in PVA 1047297lms because theanion strength o the dielectric medium has been declinedTereore the PVA polymer host is less willing to keep theelectrons in their outer layers Te single oscillator energy isan average energy gap as pointed out in many reerences [983093983088]Te 0 value o the 1047297lms is related empirically to the lowestindirect bandgap by 0 asymp 103 Tis relation is in goodagreement with the single oscillator model

7272019 pva films

httpslidepdfcomreaderfullpva-films 911

Journal o Nanomaterials 983097

10 105 11 115 12 125 1302

04

06

08

1

12

14

16

PVA

S1

S2

S3

(

n 2

minus

1 ) minus 1

E2 (eV2)

F983145983143983157983154983141 983089983093Plot o (2minus1) versus squared photon energy o pure PVAand doping samples

983137983138983148983141 983089 Dispersion parameters o 1047297lmsSamples 0

PVA 983089983093983094 983090983092983092 983093983089983097 983095983092983097

S983089 983089983092983096 983090983089983097 983093983088983092 983094983088983091

S983090 983089983091983095 983089983096983097 983092983097983095 983092983092983094

S983091 983089983089983097 983089983092983090 983092983096983095 983090983088983093

4 Conclusions

Preparation o silver nanoparticles by laser ablation methodat different 1047298uencies o laser pulse in pure water is investi-gated Te EM analysis revealed that generated nanoparti-

cles in this experimental condition are almost spherical andtheir average size was 983094ndash983089983090 nm and with increasing the laserpulse 1047298uence the size o nanoparticles is decreased Te X-ray diffraction spectrum reveals that the number o crystal-lographic planes at certain angles is increased afer doping Agnanoparticles in the structure o PVA FIR spectrum peakscorrespond to molecular vibrations and chemical bondsindicate the presence o silver in the PVA polymer structureTe optical bandgap energy o the samples is decreasedwith increasing the concentrations o silver nanoparticlesReractive index and dielectric constant are decreased withincreasing the concentration o Ag nanoparticles Increaseo dopant concentration resulted in a decrease in real part

o the optical conductivity because o segregation effectTe reractive index and consequently the related dispersionparameters o PVA and doped PVA have been determinedand explained using the Wemple-DiDomenico model

References

[983089] A Nimrodh Ananth and S Umapathy ldquoOn the optical andthermal properties o in situex situ reduced Ag NPrsquosPVAcomposites and its role as a simple SPR-based protein sensorrdquo Applied Nanoscience vol 983089 no 983090 pp 983096983095ndash983097983094 983090983088983089983089

[983090] G Nesher G Marom and D Avnir ldquoMetal-polymer compos-ites synthesis and characterization o polyaniline and other

polymer at Silver compositionsrdquo Chemistry of Materialsvol983090983088no 983089983091 pp 983092983092983090983093ndash983092983092983091983090 983090983088983088983096

[983091] P-H Wang Y-Z Wu andQ-R ZhuldquoPolymermetal compositeparticles polymer core and metal shellrdquo Journal of MaterialsScience Letters vol 983090983089 no 983090983091 pp 983089983096983090983093ndash983089983096983090983096 983090983088983088983090

[983092] S Clemenson P Alcouffe L David and E Espuche ldquoStructureand morphology o membranes prepared rom polyvinyl alco-hol and silver nitrate in1047298uence o the annealing treatment ando the 1047297lm thicknessrdquo Desalination vol 983090983088983088 no 983089-983091 pp 983092983091983095ndash983092983091983097 983090983088983088983094

[983093] K Akamatsu S akei M Mizuhata et al ldquoPreparation andcharacterization o polymer thin 1047297lms containing silver andsilver sul1047297de nanoparticlesrdquo Tin Solid Films vol 983091983093983097 no 983089 pp983093983093ndash983094983088 983090983088983088983088

[983094] R Zeng M Z Rong M Q Zhang H C Liang and H MZeng ldquoLaser ablation o polymer-based silver nanocompositesrdquo Applied Surface Science vol 983089983096983095 no 983091-983092 pp 983090983091983097ndash983090983092983095 983090983088983088983090

[983095] S Mahendia A K omar and S Kumar ldquoElectrical conduc-tivity and dielectric spectroscopic studies o PVA-Ag nanocom-posite 1047297lmsrdquo Journal of Alloys and Compounds vol 983093983088983096 no 983090pp 983092983088983094ndash983092983089983089 983090983088983089983088

[983096] N Singh and P K Khanna ldquoIn situ synthesis o silver nano-particles in polymethylmethacrylaterdquo Materials Chemistry and Physics vol 983089983088983092 no 983090-983091 pp 983091983094983095ndash983091983095983090 983090983088983088983095

[983097] P K Khanna R Gokhale V V V S Subbarao A K Vish-wanath B K Das and C V V Satyanarayana ldquoPVA stabilizedgold nanoparticles by use o unexplored albeit conventionalreducing agentrdquo Materials Chemistry and Physics vol 983097983090 no983089 pp 983090983090983097ndash983090983091983091 983090983088983088983093

[983089983088] K Akamatsu S akei M Mizuhata et al ldquoPreparation andcharacterization o polymer thin 1047297lms containing silver andsilver sul1047297de nanoparticlesrdquo Tin Solid Films vol 983091983093983097 no 983089 pp983093983093ndash983094983088 983090983088983088983088

[983089983089] I Hussain M Brust A J Papworth and A I Cooper

ldquoPreparationo acrylate-stabilized goldand silver hydrosols andgold-polymer composite 1047297lmsrdquo Langmuir vol 983089983097 no 983089983089 pp983092983096983091983089ndash983092983096983091983093 983090983088983088983091

[983089983090] S A Zavyalov A N Pivkina and J Schoonman ldquoFormationand characterization o metal-polymer nanostructured com-positesrdquo Solid State Ionics vol 983089983092983095 no 983091-983092 pp 983092983089983093ndash983092983089983097 983090983088983088983090

[983089983091] J Lee D Bhattacharyya A J Easteal and J B Metson ldquoProp-erties o nano-ZnOpoly(vinyl alcohol)poly(ethylene oxide)composite thin 1047297lmsrdquo Current Applied Physics vol 983096 no 983089 pp983092983090ndash983092983095 983090983088983088983096

[983089983092] Z Zhong D Wang Y Cui M W Bockrath and C H LieberldquoNanowire crossbar arrays as address decoders or integratednanosystemsrdquo Science vol 983091983088983090 no 983093983094983092983097 pp 983089983091983095983095ndash983089983091983095983097 983090983088983088983091

[983089983093] D S Hopkins D Pekker P M Goldbart and A Bezryadin

ldquoQuantum intererence device made by DNA templating o superconducting nanowiresrdquo Science vol 983091983088983096 no 983093983095983090983097 pp983089983095983094983090ndash983089983095983094983093 983090983088983088983093

[983089983094] S Clemenson D Leonard D Sage L David and E EspucheldquoMetal nanocomposite 1047297lms prepared in Situ rom PVA andsilver nitrate Study o the nanostructuration process andmorphology as a unction o the in Situ routesrdquo Journal of Polymer Science A vol 983092983094 no 983094 pp 983090983088983094983090ndash983090983088983095983089 983090983088983088983096

[983089983095] M K emgire and S S Joshi ldquoOptical and structural studies o silver nanoparticlesrdquo Radiation Physics and Chemistry vol 983095983089no 983093 pp 983089983088983091983097ndash983089983088983092983092 983090983088983088983092

[983089983096] M Zheng M Gu Y Jin and G Jin ldquoOptical properties o silver-dispersed PVP thin 1047297lmrdquo Materials Research Bulletin vol 983091983094no 983093-983094 pp 983096983093983091ndash983096983093983097 983090983088983088983089

7272019 pva films

httpslidepdfcomreaderfullpva-films 1011

983089983088 Journal o Nanomaterials

[983089983097] O L A Monti J Fourkas and D J Nesbitt ldquoDiffraction-limited photogeneration and characterization o silver nanopar-ticlesrdquo Journal of Physical Chemistry B vol 983089983088983096 no 983093 pp 983089983094983088983092ndash983089983094983089983090 983090983088983088983092

[983090983088] K L Kelly E Coronado L L Zhao and G C Schatz ldquoTeopti-cal properties o metal nanoparticles the in1047298uence o sizeshape and dielectric environmentrdquo Journal of Physical Che-

mistry B vol 983089983088983095 no 983091 pp 983094983094983096ndash983094983095983095 983090983088983088983091

[983090983089] H Weickmann J C iller R Tomann and R MulhauptldquoMetallized organoclays as new intermediates or aqueous nan-ohybrid dispersions nanohybrid catalysts and antimicrobialpolymer hybrid nanocompositesrdquo Macromolecular Materialsand Engineering vol 983090983097983088 no 983097 pp 983096983095983093ndash983096983096983091 983090983088983088983093

[983090983090] U Keirbeg and M Vollmer Optical Properties of Metal Clusters vol 983090983093 o Springer Series in Material Science 983089983097983097983093

[983090983091] S Chen and J M Sommers ldquoAlkanethiolate-protected coppernanoparticles spectroscopy electrochemistry and solid-statemorphological evolutionrdquo Journal of Physical Chemistry B vol983089983088983093 no 983091983095 pp 983096983096983089983094ndash983096983096983090983088 983090983088983088983089

[983090983092] A A Scalisi G Compagnini L DrsquoUrso and O Puglisi ldquoNon-linearopticalactivity in Ag-SiO

2 nanocomposite thin 1047297lms with

different silver concentrationrdquo Applied Surface Science vol 983090983090983094no 983089ndash983091 pp 983090983091983095ndash983090983092983089 983090983088983088983092

[983090983093] G Yang W Wang Y Zhou H Lu G Yang and Z Chen ldquoLin-ear and nonlinear optical properties o Ag nanoclusterBaiO3

composite 1047297lmsrdquo Applied Physics Letters vol 983096983089 no 983090983089 pp983091983097983094983097ndash983091983097983095983089 983090983088983088983090

[983090983094] H B Liao R F Xiao H Wang K S Wong and G K L WongldquoLarge third-order optical nonlinearity in AuiO2 composite1047297lms measured on a emtosecond time scalerdquo Applied PhysicsLetters vol 983095983090 no 983089983093 pp 983089983096983089983095ndash983089983096983089983097 983089983097983097983096

[983090983095] A K Sarychev D J Bergman and Y Yagil ldquoTeory o theoptical and microwave properties o metal-dielectric 1047297lmsrdquoPhysical Review B vol 983093983089 no 983096 pp 983093983091983094983094ndash983093983091983096983093 983089983097983097983093

[983090983096] G Mie ldquoBeitrage zur Optik truber Medien speziell kolloidalerMetallosungenrdquo Annalen der Physik vol 983091983091983088 pp 983091983095983095ndash983092983092983093 983089983097983088983096

[983090983097] R Gans ldquoUber die Form ultramikroskopischer Silberteilchenrdquo Annalen der Physik vol 983091983093983090 no 983089983088 pp 983090983095983088ndash983090983096983092 983089983097983089983093

[983091983088] S Link and M A El-Sayed ldquoSpectral properties and relaxationdynamics o surace plasmon electronic oscillations in gold andsilver nanodots and nanorodsrdquo Journal of Physical Chemistry B vol 983089983088983091 no 983092983088 pp 983096983092983089983088ndash983096983092983090983094 983089983097983097983097

[983091983089] G Fussell J Tomas J Scanlon A Lowman and M Mar-colongo ldquoTe effect o protein-ree versus protein-containingmedium on the mechanical properties and uptake o ions o PVAPVP hydrogelsrdquo Journalof BiomaterialsScience vol983089983094 no983092 pp 983092983096983097ndash983093983088983091 983090983088983088983093

[983091983090] suji Mizuki S Ozono and M suji ldquoLaser-induced sil-

ver nanocrystal ormation in polyvinylpyrrolidone solutionsrdquo Journal of Photochemistry and Photobiology A vol 983090983088983094 no 983090-983091pp 983089983091983092ndash983089983091983097 983090983088983088983097

[983091983091] J-P Sylvestre S Poulin A V Kabashin E Sacher M Meunierand J H Luong ldquoSurace chemistry o gold nanoparticlesproduced by laser ablation in aqueous mediardquo Journal of Physical Chemistry B vol 983089983088983096 no 983092983091 pp 983089983094983096983094983092ndash983089983094983096983094983097 983090983088983088983092

[983091983092] A Gautam and S Ram ldquoPreparation and thermomechanicalproperties o Ag-PVA nanocomposite 1047297lmsrdquo Materials Chem-istry and Physics vol 983089983089983097 no 983089-983090 pp 983090983094983094ndash983090983095983089 983090983088983089983088

[983091983093] I Saini J Rozra N Chandak S Aggarwal P K Sharmaand A Sharma ldquoailoring o electrical optical and structuralproperties o PVA by addition o Ag nanoparticlesrdquo MaterChem Phys vol 983089983091983097 pp 983096983088983090ndash983096983089983088 983090983088983089983091

[983091983094] S Mahendia A K omar and S Kumar ldquoNano-Ag dopinginduced changes in optical and electrical behaviour o PVA1047297lmsrdquo Materials Science and Engineering B vol 983089983095983094 no 983095 pp983093983091983088ndash983093983091983092 983090983088983089983089

[983091983095] M Abdelaziz and E M Abdelrazek ldquoEffect o dopant mixtureon structural optical and electron spin resonance properties o polyvinyl alcoholrdquo Physica B vol 983091983097983088 no 983089-983090 pp 983089ndash983097 983090983088983088983095

[983091983096] B Suo X Su J Wu D Chen A Wang and Z Guo ldquoPoly (vinyl alcohol) thin 1047297lm 1047297lled with CdSe-ZnS quantum dotsabrication characterization and optical propertiesrdquo MaterialsChemistry and Physics vol 983089983089983097 no 983089-983090 pp 983090983091983095ndash983090983092983090 983090983088983089983088

[983091983097] B Karthikeyan ldquoSpectroscopic studies on Ag-polyvinyl alcoholnanocomposite 1047297lmsrdquo Physica B vol 983091983094983092 no 983089ndash983092 pp 983091983090983096ndash983091983091983090983090983088983088983093

[983092983088] A S Kutsenko and V M Granchak ldquoPhotochemical synthesiso silver nanoparticles in polyvinyl alcohol matricesrdquo Teoreti-cal and Experimental Chemistry vol 983092983093no 983093 pp 983091983089983091ndash983091983089983096983090983088983088983097

[983092983089] C U Devi A K Sharma and V V R N Rao ldquoElectrical andoptical properties o pure and silver nitrate-doped polyvinylalcohol 1047297lmsrdquo Materials Letters vol 983093983094 no 983091 pp 983089983094983095ndash983089983095983092 983090983088983088983090

[983092983090] B G Streetman Solid State Electronic Devices Prentice HallNew Jersey NJ USA 983091rd edition 983089983097983097983088

[983092983091] J auc and R Grigorovici ldquoOptical properties and electronicstructure o amorphous germaniumrdquo Physica Status Solidi (B) vol 983089983093 no 983090 pp 983094983090983095ndash983094983091983095 983089983097983094983094

[983092983092] J Rozra I Saini A Sharma et al ldquoCu nanoparticles inducedstructural optical and electrical modi1047297cation in PVArdquo Materi-als Chemistry and Physics vol 983089983091983092 no 983090-983091 pp 983089983089983090983089ndash983089983089983090983094 983090983088983089983090

[983092983093] M Abdelaziz ldquoCerium (III) doping effects on optical andthermal properties o PVA 1047297lmsrdquo Physica B vol 983092983088983094 no 983094-983095pp 983089983091983088983088ndash983089983091983088983095 983090983088983089983089

[983092983094] C Kittle Introduction to Solid State Physics vol 983092983088983093 John Wiley amp Sons New York NY USA 983089983097983095983089

[983092983095] J D Jackson Classical Electrodynamics John Wiley amp Sons 983091rdedition 983089983097983097983097

[983092983096] M S Dresselhaus Solid State Physics Part II Optical Propertiesof Solids vol 983094 983090983088983088983089

[983092983097] J N Hodgson Optical Absorption and Dispersion in Solids Chapman amp Hall London UK 983089983097983095983089

[983093983088] Y Caglar S Ilican and M Caglar ldquoSingle-oscillator modeland determination o optical constants o spray pyrolyzedamorphous SnO2 thin 1047297lmsrdquo European Physical Journal B vol983093983096 no 983091 pp 983090983093983089ndash983090983093983094 983090983088983088983095

[983093983089] Y Seok Kim Electrical Conductivity of Segregated NetworkPolymer Nanoposites vol 983089983091983095 983090983088983088983095

[983093983090] Y Feldman A Puzenko and Y Ryabov ldquoDielectric relaxationphenomena in complex materialsrdquo in Advances in Chemical

Physics vol 983089983091983091 pp 983089ndash983089983090983093 Department o Applied Physics TeHebrew University o Jerusalem Jerusalem Israel 983090983088983088983094

[983093983091] S Mahendia A K omar R P Chahal P Goyal and S KumarldquoOptical and structural properties o poly(vinyl alcohol) 1047297lmsembedded with citrate-stabilized gold nanoparticlesrdquo Journal of Physics D vol 983092983092 no 983090983088 Article ID 983090983088983093983089983088983093 983090983088983089983089

[983093983092] S H Wemple and M DiDomenico ldquoBehavior o the electronicdielectric constant in covalent and ionic materialsrdquo Physical Review B vol 983091 no 983092 pp 983089983091983091983096ndash983089983091983093983089 983089983097983095983089

7272019 pva films

httpslidepdfcomreaderfullpva-films 1111

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2013Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The ScientifcWorld Journal

Impact Factor 1730

28 Days Fast Track Peer Review

All Subject Areas of Science

Submit at httpwwwtswjcom

7272019 pva films

httpslidepdfcomreaderfullpva-films 511

Journal o Nanomaterials 983093

500 1000 1500 2000 2500 3000 3500 40000

20

40

60

80

100

120

T

r a n s m i t t a n c e

Wavenumbers (cmminus1)

PVA

S1

S2

S3

F983145983143983157983154983141 983092 FIR spectrum o PVA pure 1047297lm and Ag nanoparticledoped in PVA polymer 1047297lms

200 400 600 800 1000 1200 1400 1600 1800 20000

01

02

03

04

05

06

07

0809

1

Wavelength (nm)

PVA

S1

S2

S3

Transmittance

Re1047298ectance

F983145983143983157983154983141 983093 Optical transmittance and re1047298ectance spectrum o sam-ples

are shown in Figure 983093 Pure PVA is a colorless polymerwithout any noticeable absorption in the visible range Tesharp increase observed in transmittance spectrum in therange o 983090983089983088 to 983090983092983096 nm is due to the presence o the PVApolymer bandgap [983089] Tis 1047297gure clearly indicates that aferadding nano-Ag in PVA polymer a valley at 983092983089983097 nm hasbeen created that its intensity continuously increasing withincreasing concentration o the dopant Tis new valley is

attributed to the ormation o charge transer complexes [983092983089]Te appearance o this valley in the visible region is dueto the surace plasmon resonance (SPR) nature o the Agnanoparticles embedded in PVA polymer dielectric medium

Aferdoping Ag nanoparticles in PVA polymer the re1047298ec-tion with increasing concentration o silver nanoparticlesdue to local 1047298uctuations charged particles declined

Te optical absorption coefficients o samples are evalu-ated rom the transmittance data using [983092983090]

1038389 = 1 ln 1048667

983131

(1 minus )22 + radic (1 minus )442 + 21048669

983133

(983089)

0 1 2 3 4 5 6 70

5

10

15

20

25

30

35

40

Photon energy (eV)

PVA

S1

S2

S3

A b s o r p t i o n

c o e

ffi c i e n t ( m m minus 1 )

F983145983143983157983154983141 983094 Optical absorption coefficient o 1047297lms

where and are the transmittance and re1047298ection respec-tively 1038389 is the absorption coefficient and is the thickness o the 1047297lms Figure 983094 presents the optical absorption coefficientsor undoped and nano-Ag doped PVA 1047297lms versus photonenergies Te absorption peak at 983090983097983093 eV or Ag nanoparticlesdoped in PVA polymer 1047297lms represents the characteristicsurace plasmon resonance dedicated to silver nanoparticlesTe presence o nanoparticles in the polymer 1047297lms could beconveniently ollowed by monitoringthe plasmon absorptionpeaks in the absorption spectrum Te larger absorptionpeak appeared in UV range is due to the energy gap o the PVA polymer which decreases owing to increasing theconcentration o Ag nanoparticles in the structure o the1047297lms Te position o the absorption edge was determinedby extrapolating the linear part o 1038389 versus ℎ] curves to zeroabsorption value [983092983089] Te band edge showed a decrease withincreasing concentration o Ag nanoparticles in PVA matrixTe absorption edge shifs towards higher wavelength indi-cating the decrease in the optical bandgap orthe doped 1047297lmsShifo the absorptionedgein the UVregionis due tochangesin the electron hole in the conduction and valence bands

Te most used method or estimation o the bandgapenergy rom optical measurement is the one proposed by auc and Grigorovici [983092983091] Te optical bandgap energy o samples was deduced rom the intercept o the extrapolated

linear part o the plot o (1038389)12 versus the photon energy with abscissa (Figure 983095) Tis ollows by the method o aucwhere

1038389 = 1048616 minus 10486171038389 (983090)

In this equation 1038389() is the absorption coefficient isthe photon energy is a actor that depends on transitionprobability and can be assumed to be constant within theoptical requency range and the index that is related tothe distribution o the density o states is an index whichassumes the values 983089983090 983091983090 983090 and 983091 depending on the natureo electronic transition aking = 2 which correspondsto indirectly allowed transition in pure PVA 1047297lm and nano-Ag doped PVA 1047297lms the bandgap energies o 1047297lms were

7272019 pva films

httpslidepdfcomreaderfullpva-films 611

983094 Journal o Nanomaterials

0 1 2 3 4 5 6 70

2

4

6

8

10

12

14

16

Photon energy (eV)

( 1038389 E ) 1 2

( m m minus 1 2 e V 1 2 )

PVA

S1

S2

S3

F983145983143983157983154983141 983095 (1038389)12 versus photon energy to illustrate auc method

calculated In an indirect gap a photon cannot be emittedbecause the electron must pass through an intermediatestate and transer momentum to the crystal lattice Teenergy gap o pure PVA sample is equal to 983092983097983094 eV andwith increasing the concentration o the Ag-nanoparticlesin the structure o 1047297lms bandgap energy is decreased Teextracted bandgap energy o sample are 983092983096983095 983092983096983092 and983092983095983096 eV or sample 983089ndash983091 respectively Te incorporation o the silver nanoparticles irrespective o their methodology o synthesis also affects the bandgap o the involved polymersystem Tis also con1047297rms the presence o the inorganic1047297llers inside the host [983089] Te variation o the calculated

values o optical bandgap re1047298ects the role o ormationo Ag-nanoparticles in modiying the electronic structureo the PVA matrix [983092983089 983092983092] Tese Ag-nanoparticles may be responsible or the ormation o localized electronicstates in the Highest Occupied Molecular Orbital-LowestUnoccupied Molecular Orbital (HOMO-LUMO) gap Teselocalized electronic states dominate the optical and electricalproperties vis-a-vis their role as trapping and recombinationcenters thus enhancing the low energy transitions leadingto the observed change in optical bandgap Te decrease inthe optical bandgap also re1047298ects the increase in the degreeo disorder in the 1047297lms which arises due to the change inpolymer structure [983092983092 983092983093]

Optical properties such as complex reractive index anddielectric constant or a certain range o wavelength betweenultraviolet and near inrared are important criteria or theselection o abricated 1047297lms or various applications Tereractive index is one o the undamental properties o a material because it is closely related to the electronicpolarizability o ions and the local 1047297eld inside the material [983096983097] Tus to urtherunderstand the interaction o Ag nanopar-ticles with PVA matrix optical properties such as complexreractive index and dielectric constant have been calculatedusing the undamental relations o photon transmittance ()re1047298ectance () and absorbance () Te complex reractiveindex is

= + that

is the real part and the extinction

0 1 2 3 4 5 6 713

14

15

16

17

18

19

2

Photon energy (eV)

R e f r a c t i v e i n d e x

PVA

S1

S2

S3

F983145983143983157983154983141 983096 Te reractive index o 1047297lms

coefficient

is the imaginary part Te reractive index

o

the 1047297lms was calculated using the ollowing equation [983092983094]

= 9830801 + 1 minus 983081 + radic 4(1 minus )2 minus 2 (983091)

in which = 110392510383894 Figures 983096 and 983097 show the photonenergy dependence o reractive index and the extinctioncoefficient or pure PVA and nano-Ag doped PVA 1047297lms Itcan be discerned rom Figure 983096 that the reractive index o nano-Ag doped PVA 1047297lms is lower than the reractive indexo pure PVA and it decreases with increasing concentrationo Ag nanoparticles in PVA matrix Tis property is inherentin all conductors and due to localized 1047298uctuation o charged

particles in medium Also decreasing the value o reractiveindex may be an indication o low density o 1047297lms whichleads to increasing the interatomic spacing [983092983093]Tisisduetoormation o intermolecular hydrogen bonding between Ag-nanoparticles and the adjacent OH groups Te dependenceo the reractive index on the 1047297lm density can be discussed by the well-known Clausius-Mossotti relation [983092983094]

Te extinction coefficient describes the properties o the material with respect to light o a given wavelength andindicates the absorption changes when the electromagneticwavepropagates through the material In Figure 983097 the extinc-tion coefficient o the doped samples have a peak at =295 eV which increases with increasing concentration o Ag nanoparticles in PVA dielectric medium Te extinctioncoefficient increases due to surace plasmon absorption indoped samples while the reractive index decreases in thisregion Tere is anomalous dispersion regions when 225 lt lt 2983097983093 eV and gt 485 eV as well as normal dispersionwhen 295 lt lt 345 eV or doped samples

Te complex dielectric unction is = 1103925 + 907317 where1103925 is the real part and 907317 is the imaginary part o dielectricconstant Te real and imaginary parts o dielectric constantare expressed as

1103925 = 2 minus 2907317 = 2 (983092)

7272019 pva films

httpslidepdfcomreaderfullpva-films 711

Journal o Nanomaterials 983095

0 1 2 3 4 5 6 70

1

2

3

4

5

6

7

8

Photon energy (eV)

E x t i n c t i o

n c o e

ffi c i e n t

PVA

S1

S2

S3

times10minus4

F983145983143983157983154983141 983097 Te extinction coefficient spectrum o 1047297lms

0 1 2 3 4 5 6 715

2

25

3

35

4

Photon energy (eV)

PVA

S1

S2

S3

1103925 r

F983145983143983157983154983141 983089983088 Real part o the dielectric constant o pure PVA and Agnanoparticle doped 1047297lms

Te real part o dielectric constant is related to the disper-sion In order to explain the dispersion it is necessary to takeinto account the actual motion o the electrons in the opticalmedium through which the light is traveling Te imaginary part represents the dissipative rate o electromagnetic wavepropagation in the medium Te real and imaginary partsdependences on photon energy o samples are shown in

Figures 983089983088 and 983089983089 respectively It can be concluded that 1103925is larger than 907317 because it mainly depends on 2 Withincreasing the amount o silver nanoparticles in PVA the realpart o dielectric constant is decreased It is due to decreaseo the dielectric property o 1047297lms because o Ag nanoparticlesmetal lattice in the host PVA polymer matrix Te normaldispersion is associated with an increase in Re() with andanomalous dispersion is associated with the reverse mecha-nism Normal dispersion is occurred everywhere expect inthe neighborhood o the resonance requency In this regionthe anomalous dispersion is appreciable Since a positiveimaginary part to 907317 represents dissipation o energy rom theelectromagnetic wave into the medium the regions where

907317

0 1 2 3 4 5 6 70

05

1

15

2

25

Photon energy (eV)

PVA

S1

S2

S3

times10minus3

1103925 i

F983145983143983157983154983141 983089983089 Imaginary part o the dielectric unction o 1047297lms

is large are called regions o resonant absorption [983092983095] Tepeak that appears in Figure 983089983089 at = 295 eV shows theplasmonic absorption

Te complex dielectric unction and complex opticalconductivity are introduced through Maxwellrsquos equationsTe interband transitions have threshold energy at the energy gap Tat is we expect the requency dependence o thereal part o the conductivity 1103925() due to an interbandtransition to exhibit a threshold or an allowed electronictransition [983092983096] In interband transition real 1103925 and imaginary 907317 components o optical conductivity are described as [983092983096ndash983093983088]

1103925 = 9073170907317 = 11039250 (983093)

where is the angular requency o electromagnetic wave and0 is the ree space dielectric constant Te real and imaginary parts o the optical conductivity dependence on the photonenergy are shown in Figures 983089983090 and 983089983091 respectively

Te real optical conductivity in bandgap energy regionafer doping the Ag-nanoparticles in PVA polymer decreasesIt can be due to the segregation effect [983092983089 983093983089] Te segregatedeffect is the dispersion o metallic particles restricted by thepresence o much larger polymeric particles Te observedeffect o Ag nanoparticles on the optical conductivity and

conduction behavior o PVA 1047297lms can be explained on thebasis o charge transer complex ormation involving PVAmolecules and the dopant When PVA polymer is mixedwith Ag nanoparticles as a result the 1047297ller is pushed intointerstitial space between the polymer particles and ormsa segregated network [983093983089] At higher dopant concentrationthere may be segregation o the dopant in the polymermatrix which decreases the conductivity Tus motion o charge carriers or localized 1047298uctuations o charged parti-cles in molecular aggregates impedes optical conductivityMoreover there is a weak peak at = 295 eV that can beseen only in the doped samples Tis new peak is attributedto the ormation o charge transer or the surace plasmon

7272019 pva films

httpslidepdfcomreaderfullpva-films 811

983096 Journal o Nanomaterials

0 1 2 3 4 5 6 70

02

04

06

08

1

12

14

16

18

2

Energy photon (eV)

PVA

S1

S2

S3

times10minus16

907317 r

( S m )

F983145983143983157983154983141 983089983090 Real part o the optical conductivity o pure PVA anddoped 1047297lms

0 1 2 3 4 5 6 70

05

1

15

2

25

3

35

Energy photon (eV)

PVA

S1

S2

S3

times10minus13

907317 i

( S m )

F983145983143983157983154983141 983089983091 Imaginary part o the optical conductivity o pure PVAand doped 1047297lms

silver nanoparticles Another result is that by increasingthe concentration o Ag nanoparticles in PVA matrix theimaginary part o optical conductivity decreases

A dielectric sample in an external electric 1047297eld acquiresa nonzero macroscopic dipole moment indicating that thedielectric is polarized under the in1047298uence o the 1047297eld Polar-ization o dielectric material achieves its equilibrium valuenot instantaneously but rather over a period o time [983093983090]Te dielectric relaxation time can be evaluated using

= infin minus 1103925907317 (983094)

Figure 983089983092 shows the dielectric relaxation time as a unc-tion o photon energy or pure PVA polymer and Agnanoparticle doped PVA 1047297lms Te valley at 983090983097983093 eV ordoped samples increases with increasing the concentrationo Ag nanoparticles in the structure o the 1047297lms In otherwords the relaxation time o dipole orientation decreases

2 25 3 35 4 45 5 550

02

04

06

08

1

12

14

16

18

2

Photon energy (eV)

R e

l a x a t

i o n t i m e

( s )

PVA

S1

S2

S3

times10minus12

F983145983143983157983154983141 983089983092 Relaxation time versus photon energy o 1047297lms

Tis is another reason or decreasing the dielectric unctionand increasing the conductivity o 1047297lms with increasing theconcentration o nanoparticles in their structure [983093983091]

Reractive index dispersion is a determinant actor inoptical materials It is a signi1047297cant actor in opticalcommuni-cation andin designingdevices orspectral dispersion[983091983093]Inthe normal dispersion region the reractive index dispersionhasbeen analyzed using thesingleoscillator model developedby theory o Wemple and DiDomenico [983093983092] Tey intro-duced a dispersion-energy parameter which connectsthe coordination number and the charge distribution withineach unit cell

is closely related to chemical bonding

Also they de1047297ned a single oscillator parameter 0 whichis proportional to the energy o oscillator In terms o thisdispersion energy and single oscillator energy 0 thereractive index at requency can be written as

12 minus 1 = 0

minus 10

(ℎ])2 (983095)

Te values o and 0 can be obtained rom the

intercept and slope o the linear part o (2 minus 1)minus1 plot versus

(ℎ]

)2 as is shown in Figure 983089983093 Also dispersion o reractive

index is controlled by the combined effects o and 0 Tecalculated values o the dispersion parameters (0 and )as well as the corresponding optical constant ( = 2) orthe pure PVA 1047297lm and samples 983089 to 983091 are listed in able 983089Te dispersion energy values decreases with increasing theconcentration o Ag nanoparticles in PVA 1047297lms because theanion strength o the dielectric medium has been declinedTereore the PVA polymer host is less willing to keep theelectrons in their outer layers Te single oscillator energy isan average energy gap as pointed out in many reerences [983093983088]Te 0 value o the 1047297lms is related empirically to the lowestindirect bandgap by 0 asymp 103 Tis relation is in goodagreement with the single oscillator model

7272019 pva films

httpslidepdfcomreaderfullpva-films 911

Journal o Nanomaterials 983097

10 105 11 115 12 125 1302

04

06

08

1

12

14

16

PVA

S1

S2

S3

(

n 2

minus

1 ) minus 1

E2 (eV2)

F983145983143983157983154983141 983089983093Plot o (2minus1) versus squared photon energy o pure PVAand doping samples

983137983138983148983141 983089 Dispersion parameters o 1047297lmsSamples 0

PVA 983089983093983094 983090983092983092 983093983089983097 983095983092983097

S983089 983089983092983096 983090983089983097 983093983088983092 983094983088983091

S983090 983089983091983095 983089983096983097 983092983097983095 983092983092983094

S983091 983089983089983097 983089983092983090 983092983096983095 983090983088983093

4 Conclusions

Preparation o silver nanoparticles by laser ablation methodat different 1047298uencies o laser pulse in pure water is investi-gated Te EM analysis revealed that generated nanoparti-

cles in this experimental condition are almost spherical andtheir average size was 983094ndash983089983090 nm and with increasing the laserpulse 1047298uence the size o nanoparticles is decreased Te X-ray diffraction spectrum reveals that the number o crystal-lographic planes at certain angles is increased afer doping Agnanoparticles in the structure o PVA FIR spectrum peakscorrespond to molecular vibrations and chemical bondsindicate the presence o silver in the PVA polymer structureTe optical bandgap energy o the samples is decreasedwith increasing the concentrations o silver nanoparticlesReractive index and dielectric constant are decreased withincreasing the concentration o Ag nanoparticles Increaseo dopant concentration resulted in a decrease in real part

o the optical conductivity because o segregation effectTe reractive index and consequently the related dispersionparameters o PVA and doped PVA have been determinedand explained using the Wemple-DiDomenico model

References

[983089] A Nimrodh Ananth and S Umapathy ldquoOn the optical andthermal properties o in situex situ reduced Ag NPrsquosPVAcomposites and its role as a simple SPR-based protein sensorrdquo Applied Nanoscience vol 983089 no 983090 pp 983096983095ndash983097983094 983090983088983089983089

[983090] G Nesher G Marom and D Avnir ldquoMetal-polymer compos-ites synthesis and characterization o polyaniline and other

polymer at Silver compositionsrdquo Chemistry of Materialsvol983090983088no 983089983091 pp 983092983092983090983093ndash983092983092983091983090 983090983088983088983096

[983091] P-H Wang Y-Z Wu andQ-R ZhuldquoPolymermetal compositeparticles polymer core and metal shellrdquo Journal of MaterialsScience Letters vol 983090983089 no 983090983091 pp 983089983096983090983093ndash983089983096983090983096 983090983088983088983090

[983092] S Clemenson P Alcouffe L David and E Espuche ldquoStructureand morphology o membranes prepared rom polyvinyl alco-hol and silver nitrate in1047298uence o the annealing treatment ando the 1047297lm thicknessrdquo Desalination vol 983090983088983088 no 983089-983091 pp 983092983091983095ndash983092983091983097 983090983088983088983094

[983093] K Akamatsu S akei M Mizuhata et al ldquoPreparation andcharacterization o polymer thin 1047297lms containing silver andsilver sul1047297de nanoparticlesrdquo Tin Solid Films vol 983091983093983097 no 983089 pp983093983093ndash983094983088 983090983088983088983088

[983094] R Zeng M Z Rong M Q Zhang H C Liang and H MZeng ldquoLaser ablation o polymer-based silver nanocompositesrdquo Applied Surface Science vol 983089983096983095 no 983091-983092 pp 983090983091983097ndash983090983092983095 983090983088983088983090

[983095] S Mahendia A K omar and S Kumar ldquoElectrical conduc-tivity and dielectric spectroscopic studies o PVA-Ag nanocom-posite 1047297lmsrdquo Journal of Alloys and Compounds vol 983093983088983096 no 983090pp 983092983088983094ndash983092983089983089 983090983088983089983088

[983096] N Singh and P K Khanna ldquoIn situ synthesis o silver nano-particles in polymethylmethacrylaterdquo Materials Chemistry and Physics vol 983089983088983092 no 983090-983091 pp 983091983094983095ndash983091983095983090 983090983088983088983095

[983097] P K Khanna R Gokhale V V V S Subbarao A K Vish-wanath B K Das and C V V Satyanarayana ldquoPVA stabilizedgold nanoparticles by use o unexplored albeit conventionalreducing agentrdquo Materials Chemistry and Physics vol 983097983090 no983089 pp 983090983090983097ndash983090983091983091 983090983088983088983093

[983089983088] K Akamatsu S akei M Mizuhata et al ldquoPreparation andcharacterization o polymer thin 1047297lms containing silver andsilver sul1047297de nanoparticlesrdquo Tin Solid Films vol 983091983093983097 no 983089 pp983093983093ndash983094983088 983090983088983088983088

[983089983089] I Hussain M Brust A J Papworth and A I Cooper

ldquoPreparationo acrylate-stabilized goldand silver hydrosols andgold-polymer composite 1047297lmsrdquo Langmuir vol 983089983097 no 983089983089 pp983092983096983091983089ndash983092983096983091983093 983090983088983088983091

[983089983090] S A Zavyalov A N Pivkina and J Schoonman ldquoFormationand characterization o metal-polymer nanostructured com-positesrdquo Solid State Ionics vol 983089983092983095 no 983091-983092 pp 983092983089983093ndash983092983089983097 983090983088983088983090

[983089983091] J Lee D Bhattacharyya A J Easteal and J B Metson ldquoProp-erties o nano-ZnOpoly(vinyl alcohol)poly(ethylene oxide)composite thin 1047297lmsrdquo Current Applied Physics vol 983096 no 983089 pp983092983090ndash983092983095 983090983088983088983096

[983089983092] Z Zhong D Wang Y Cui M W Bockrath and C H LieberldquoNanowire crossbar arrays as address decoders or integratednanosystemsrdquo Science vol 983091983088983090 no 983093983094983092983097 pp 983089983091983095983095ndash983089983091983095983097 983090983088983088983091

[983089983093] D S Hopkins D Pekker P M Goldbart and A Bezryadin

ldquoQuantum intererence device made by DNA templating o superconducting nanowiresrdquo Science vol 983091983088983096 no 983093983095983090983097 pp983089983095983094983090ndash983089983095983094983093 983090983088983088983093

[983089983094] S Clemenson D Leonard D Sage L David and E EspucheldquoMetal nanocomposite 1047297lms prepared in Situ rom PVA andsilver nitrate Study o the nanostructuration process andmorphology as a unction o the in Situ routesrdquo Journal of Polymer Science A vol 983092983094 no 983094 pp 983090983088983094983090ndash983090983088983095983089 983090983088983088983096

[983089983095] M K emgire and S S Joshi ldquoOptical and structural studies o silver nanoparticlesrdquo Radiation Physics and Chemistry vol 983095983089no 983093 pp 983089983088983091983097ndash983089983088983092983092 983090983088983088983092

[983089983096] M Zheng M Gu Y Jin and G Jin ldquoOptical properties o silver-dispersed PVP thin 1047297lmrdquo Materials Research Bulletin vol 983091983094no 983093-983094 pp 983096983093983091ndash983096983093983097 983090983088983088983089

7272019 pva films

httpslidepdfcomreaderfullpva-films 1011

983089983088 Journal o Nanomaterials

[983089983097] O L A Monti J Fourkas and D J Nesbitt ldquoDiffraction-limited photogeneration and characterization o silver nanopar-ticlesrdquo Journal of Physical Chemistry B vol 983089983088983096 no 983093 pp 983089983094983088983092ndash983089983094983089983090 983090983088983088983092

[983090983088] K L Kelly E Coronado L L Zhao and G C Schatz ldquoTeopti-cal properties o metal nanoparticles the in1047298uence o sizeshape and dielectric environmentrdquo Journal of Physical Che-

mistry B vol 983089983088983095 no 983091 pp 983094983094983096ndash983094983095983095 983090983088983088983091

[983090983089] H Weickmann J C iller R Tomann and R MulhauptldquoMetallized organoclays as new intermediates or aqueous nan-ohybrid dispersions nanohybrid catalysts and antimicrobialpolymer hybrid nanocompositesrdquo Macromolecular Materialsand Engineering vol 983090983097983088 no 983097 pp 983096983095983093ndash983096983096983091 983090983088983088983093

[983090983090] U Keirbeg and M Vollmer Optical Properties of Metal Clusters vol 983090983093 o Springer Series in Material Science 983089983097983097983093

[983090983091] S Chen and J M Sommers ldquoAlkanethiolate-protected coppernanoparticles spectroscopy electrochemistry and solid-statemorphological evolutionrdquo Journal of Physical Chemistry B vol983089983088983093 no 983091983095 pp 983096983096983089983094ndash983096983096983090983088 983090983088983088983089

[983090983092] A A Scalisi G Compagnini L DrsquoUrso and O Puglisi ldquoNon-linearopticalactivity in Ag-SiO

2 nanocomposite thin 1047297lms with

different silver concentrationrdquo Applied Surface Science vol 983090983090983094no 983089ndash983091 pp 983090983091983095ndash983090983092983089 983090983088983088983092

[983090983093] G Yang W Wang Y Zhou H Lu G Yang and Z Chen ldquoLin-ear and nonlinear optical properties o Ag nanoclusterBaiO3

composite 1047297lmsrdquo Applied Physics Letters vol 983096983089 no 983090983089 pp983091983097983094983097ndash983091983097983095983089 983090983088983088983090

[983090983094] H B Liao R F Xiao H Wang K S Wong and G K L WongldquoLarge third-order optical nonlinearity in AuiO2 composite1047297lms measured on a emtosecond time scalerdquo Applied PhysicsLetters vol 983095983090 no 983089983093 pp 983089983096983089983095ndash983089983096983089983097 983089983097983097983096

[983090983095] A K Sarychev D J Bergman and Y Yagil ldquoTeory o theoptical and microwave properties o metal-dielectric 1047297lmsrdquoPhysical Review B vol 983093983089 no 983096 pp 983093983091983094983094ndash983093983091983096983093 983089983097983097983093

[983090983096] G Mie ldquoBeitrage zur Optik truber Medien speziell kolloidalerMetallosungenrdquo Annalen der Physik vol 983091983091983088 pp 983091983095983095ndash983092983092983093 983089983097983088983096

[983090983097] R Gans ldquoUber die Form ultramikroskopischer Silberteilchenrdquo Annalen der Physik vol 983091983093983090 no 983089983088 pp 983090983095983088ndash983090983096983092 983089983097983089983093

[983091983088] S Link and M A El-Sayed ldquoSpectral properties and relaxationdynamics o surace plasmon electronic oscillations in gold andsilver nanodots and nanorodsrdquo Journal of Physical Chemistry B vol 983089983088983091 no 983092983088 pp 983096983092983089983088ndash983096983092983090983094 983089983097983097983097

[983091983089] G Fussell J Tomas J Scanlon A Lowman and M Mar-colongo ldquoTe effect o protein-ree versus protein-containingmedium on the mechanical properties and uptake o ions o PVAPVP hydrogelsrdquo Journalof BiomaterialsScience vol983089983094 no983092 pp 983092983096983097ndash983093983088983091 983090983088983088983093

[983091983090] suji Mizuki S Ozono and M suji ldquoLaser-induced sil-

ver nanocrystal ormation in polyvinylpyrrolidone solutionsrdquo Journal of Photochemistry and Photobiology A vol 983090983088983094 no 983090-983091pp 983089983091983092ndash983089983091983097 983090983088983088983097

[983091983091] J-P Sylvestre S Poulin A V Kabashin E Sacher M Meunierand J H Luong ldquoSurace chemistry o gold nanoparticlesproduced by laser ablation in aqueous mediardquo Journal of Physical Chemistry B vol 983089983088983096 no 983092983091 pp 983089983094983096983094983092ndash983089983094983096983094983097 983090983088983088983092

[983091983092] A Gautam and S Ram ldquoPreparation and thermomechanicalproperties o Ag-PVA nanocomposite 1047297lmsrdquo Materials Chem-istry and Physics vol 983089983089983097 no 983089-983090 pp 983090983094983094ndash983090983095983089 983090983088983089983088

[983091983093] I Saini J Rozra N Chandak S Aggarwal P K Sharmaand A Sharma ldquoailoring o electrical optical and structuralproperties o PVA by addition o Ag nanoparticlesrdquo MaterChem Phys vol 983089983091983097 pp 983096983088983090ndash983096983089983088 983090983088983089983091

[983091983094] S Mahendia A K omar and S Kumar ldquoNano-Ag dopinginduced changes in optical and electrical behaviour o PVA1047297lmsrdquo Materials Science and Engineering B vol 983089983095983094 no 983095 pp983093983091983088ndash983093983091983092 983090983088983089983089

[983091983095] M Abdelaziz and E M Abdelrazek ldquoEffect o dopant mixtureon structural optical and electron spin resonance properties o polyvinyl alcoholrdquo Physica B vol 983091983097983088 no 983089-983090 pp 983089ndash983097 983090983088983088983095

[983091983096] B Suo X Su J Wu D Chen A Wang and Z Guo ldquoPoly (vinyl alcohol) thin 1047297lm 1047297lled with CdSe-ZnS quantum dotsabrication characterization and optical propertiesrdquo MaterialsChemistry and Physics vol 983089983089983097 no 983089-983090 pp 983090983091983095ndash983090983092983090 983090983088983089983088

[983091983097] B Karthikeyan ldquoSpectroscopic studies on Ag-polyvinyl alcoholnanocomposite 1047297lmsrdquo Physica B vol 983091983094983092 no 983089ndash983092 pp 983091983090983096ndash983091983091983090983090983088983088983093

[983092983088] A S Kutsenko and V M Granchak ldquoPhotochemical synthesiso silver nanoparticles in polyvinyl alcohol matricesrdquo Teoreti-cal and Experimental Chemistry vol 983092983093no 983093 pp 983091983089983091ndash983091983089983096983090983088983088983097

[983092983089] C U Devi A K Sharma and V V R N Rao ldquoElectrical andoptical properties o pure and silver nitrate-doped polyvinylalcohol 1047297lmsrdquo Materials Letters vol 983093983094 no 983091 pp 983089983094983095ndash983089983095983092 983090983088983088983090

[983092983090] B G Streetman Solid State Electronic Devices Prentice HallNew Jersey NJ USA 983091rd edition 983089983097983097983088

[983092983091] J auc and R Grigorovici ldquoOptical properties and electronicstructure o amorphous germaniumrdquo Physica Status Solidi (B) vol 983089983093 no 983090 pp 983094983090983095ndash983094983091983095 983089983097983094983094

[983092983092] J Rozra I Saini A Sharma et al ldquoCu nanoparticles inducedstructural optical and electrical modi1047297cation in PVArdquo Materi-als Chemistry and Physics vol 983089983091983092 no 983090-983091 pp 983089983089983090983089ndash983089983089983090983094 983090983088983089983090

[983092983093] M Abdelaziz ldquoCerium (III) doping effects on optical andthermal properties o PVA 1047297lmsrdquo Physica B vol 983092983088983094 no 983094-983095pp 983089983091983088983088ndash983089983091983088983095 983090983088983089983089

[983092983094] C Kittle Introduction to Solid State Physics vol 983092983088983093 John Wiley amp Sons New York NY USA 983089983097983095983089

[983092983095] J D Jackson Classical Electrodynamics John Wiley amp Sons 983091rdedition 983089983097983097983097

[983092983096] M S Dresselhaus Solid State Physics Part II Optical Propertiesof Solids vol 983094 983090983088983088983089

[983092983097] J N Hodgson Optical Absorption and Dispersion in Solids Chapman amp Hall London UK 983089983097983095983089

[983093983088] Y Caglar S Ilican and M Caglar ldquoSingle-oscillator modeland determination o optical constants o spray pyrolyzedamorphous SnO2 thin 1047297lmsrdquo European Physical Journal B vol983093983096 no 983091 pp 983090983093983089ndash983090983093983094 983090983088983088983095

[983093983089] Y Seok Kim Electrical Conductivity of Segregated NetworkPolymer Nanoposites vol 983089983091983095 983090983088983088983095

[983093983090] Y Feldman A Puzenko and Y Ryabov ldquoDielectric relaxationphenomena in complex materialsrdquo in Advances in Chemical

Physics vol 983089983091983091 pp 983089ndash983089983090983093 Department o Applied Physics TeHebrew University o Jerusalem Jerusalem Israel 983090983088983088983094

[983093983091] S Mahendia A K omar R P Chahal P Goyal and S KumarldquoOptical and structural properties o poly(vinyl alcohol) 1047297lmsembedded with citrate-stabilized gold nanoparticlesrdquo Journal of Physics D vol 983092983092 no 983090983088 Article ID 983090983088983093983089983088983093 983090983088983089983089

[983093983092] S H Wemple and M DiDomenico ldquoBehavior o the electronicdielectric constant in covalent and ionic materialsrdquo Physical Review B vol 983091 no 983092 pp 983089983091983091983096ndash983089983091983093983089 983089983097983095983089

7272019 pva films

httpslidepdfcomreaderfullpva-films 1111

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2013Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The ScientifcWorld Journal

Impact Factor 1730

28 Days Fast Track Peer Review

All Subject Areas of Science

Submit at httpwwwtswjcom

7272019 pva films

httpslidepdfcomreaderfullpva-films 611

983094 Journal o Nanomaterials

0 1 2 3 4 5 6 70

2

4

6

8

10

12

14

16

Photon energy (eV)

( 1038389 E ) 1 2

( m m minus 1 2 e V 1 2 )

PVA

S1

S2

S3

F983145983143983157983154983141 983095 (1038389)12 versus photon energy to illustrate auc method

calculated In an indirect gap a photon cannot be emittedbecause the electron must pass through an intermediatestate and transer momentum to the crystal lattice Teenergy gap o pure PVA sample is equal to 983092983097983094 eV andwith increasing the concentration o the Ag-nanoparticlesin the structure o 1047297lms bandgap energy is decreased Teextracted bandgap energy o sample are 983092983096983095 983092983096983092 and983092983095983096 eV or sample 983089ndash983091 respectively Te incorporation o the silver nanoparticles irrespective o their methodology o synthesis also affects the bandgap o the involved polymersystem Tis also con1047297rms the presence o the inorganic1047297llers inside the host [983089] Te variation o the calculated

values o optical bandgap re1047298ects the role o ormationo Ag-nanoparticles in modiying the electronic structureo the PVA matrix [983092983089 983092983092] Tese Ag-nanoparticles may be responsible or the ormation o localized electronicstates in the Highest Occupied Molecular Orbital-LowestUnoccupied Molecular Orbital (HOMO-LUMO) gap Teselocalized electronic states dominate the optical and electricalproperties vis-a-vis their role as trapping and recombinationcenters thus enhancing the low energy transitions leadingto the observed change in optical bandgap Te decrease inthe optical bandgap also re1047298ects the increase in the degreeo disorder in the 1047297lms which arises due to the change inpolymer structure [983092983092 983092983093]

Optical properties such as complex reractive index anddielectric constant or a certain range o wavelength betweenultraviolet and near inrared are important criteria or theselection o abricated 1047297lms or various applications Tereractive index is one o the undamental properties o a material because it is closely related to the electronicpolarizability o ions and the local 1047297eld inside the material [983096983097] Tus to urtherunderstand the interaction o Ag nanopar-ticles with PVA matrix optical properties such as complexreractive index and dielectric constant have been calculatedusing the undamental relations o photon transmittance ()re1047298ectance () and absorbance () Te complex reractiveindex is

= + that

is the real part and the extinction

0 1 2 3 4 5 6 713

14

15

16

17

18

19

2

Photon energy (eV)

R e f r a c t i v e i n d e x

PVA

S1

S2

S3

F983145983143983157983154983141 983096 Te reractive index o 1047297lms

coefficient

is the imaginary part Te reractive index

o

the 1047297lms was calculated using the ollowing equation [983092983094]

= 9830801 + 1 minus 983081 + radic 4(1 minus )2 minus 2 (983091)

in which = 110392510383894 Figures 983096 and 983097 show the photonenergy dependence o reractive index and the extinctioncoefficient or pure PVA and nano-Ag doped PVA 1047297lms Itcan be discerned rom Figure 983096 that the reractive index o nano-Ag doped PVA 1047297lms is lower than the reractive indexo pure PVA and it decreases with increasing concentrationo Ag nanoparticles in PVA matrix Tis property is inherentin all conductors and due to localized 1047298uctuation o charged

particles in medium Also decreasing the value o reractiveindex may be an indication o low density o 1047297lms whichleads to increasing the interatomic spacing [983092983093]Tisisduetoormation o intermolecular hydrogen bonding between Ag-nanoparticles and the adjacent OH groups Te dependenceo the reractive index on the 1047297lm density can be discussed by the well-known Clausius-Mossotti relation [983092983094]

Te extinction coefficient describes the properties o the material with respect to light o a given wavelength andindicates the absorption changes when the electromagneticwavepropagates through the material In Figure 983097 the extinc-tion coefficient o the doped samples have a peak at =295 eV which increases with increasing concentration o Ag nanoparticles in PVA dielectric medium Te extinctioncoefficient increases due to surace plasmon absorption indoped samples while the reractive index decreases in thisregion Tere is anomalous dispersion regions when 225 lt lt 2983097983093 eV and gt 485 eV as well as normal dispersionwhen 295 lt lt 345 eV or doped samples

Te complex dielectric unction is = 1103925 + 907317 where1103925 is the real part and 907317 is the imaginary part o dielectricconstant Te real and imaginary parts o dielectric constantare expressed as

1103925 = 2 minus 2907317 = 2 (983092)

7272019 pva films

httpslidepdfcomreaderfullpva-films 711

Journal o Nanomaterials 983095

0 1 2 3 4 5 6 70

1

2

3

4

5

6

7

8

Photon energy (eV)

E x t i n c t i o

n c o e

ffi c i e n t

PVA

S1

S2

S3

times10minus4

F983145983143983157983154983141 983097 Te extinction coefficient spectrum o 1047297lms

0 1 2 3 4 5 6 715

2

25

3

35

4

Photon energy (eV)

PVA

S1

S2

S3

1103925 r

F983145983143983157983154983141 983089983088 Real part o the dielectric constant o pure PVA and Agnanoparticle doped 1047297lms

Te real part o dielectric constant is related to the disper-sion In order to explain the dispersion it is necessary to takeinto account the actual motion o the electrons in the opticalmedium through which the light is traveling Te imaginary part represents the dissipative rate o electromagnetic wavepropagation in the medium Te real and imaginary partsdependences on photon energy o samples are shown in

Figures 983089983088 and 983089983089 respectively It can be concluded that 1103925is larger than 907317 because it mainly depends on 2 Withincreasing the amount o silver nanoparticles in PVA the realpart o dielectric constant is decreased It is due to decreaseo the dielectric property o 1047297lms because o Ag nanoparticlesmetal lattice in the host PVA polymer matrix Te normaldispersion is associated with an increase in Re() with andanomalous dispersion is associated with the reverse mecha-nism Normal dispersion is occurred everywhere expect inthe neighborhood o the resonance requency In this regionthe anomalous dispersion is appreciable Since a positiveimaginary part to 907317 represents dissipation o energy rom theelectromagnetic wave into the medium the regions where

907317

0 1 2 3 4 5 6 70

05

1

15

2

25

Photon energy (eV)

PVA

S1

S2

S3

times10minus3

1103925 i

F983145983143983157983154983141 983089983089 Imaginary part o the dielectric unction o 1047297lms

is large are called regions o resonant absorption [983092983095] Tepeak that appears in Figure 983089983089 at = 295 eV shows theplasmonic absorption

Te complex dielectric unction and complex opticalconductivity are introduced through Maxwellrsquos equationsTe interband transitions have threshold energy at the energy gap Tat is we expect the requency dependence o thereal part o the conductivity 1103925() due to an interbandtransition to exhibit a threshold or an allowed electronictransition [983092983096] In interband transition real 1103925 and imaginary 907317 components o optical conductivity are described as [983092983096ndash983093983088]

1103925 = 9073170907317 = 11039250 (983093)

where is the angular requency o electromagnetic wave and0 is the ree space dielectric constant Te real and imaginary parts o the optical conductivity dependence on the photonenergy are shown in Figures 983089983090 and 983089983091 respectively

Te real optical conductivity in bandgap energy regionafer doping the Ag-nanoparticles in PVA polymer decreasesIt can be due to the segregation effect [983092983089 983093983089] Te segregatedeffect is the dispersion o metallic particles restricted by thepresence o much larger polymeric particles Te observedeffect o Ag nanoparticles on the optical conductivity and

conduction behavior o PVA 1047297lms can be explained on thebasis o charge transer complex ormation involving PVAmolecules and the dopant When PVA polymer is mixedwith Ag nanoparticles as a result the 1047297ller is pushed intointerstitial space between the polymer particles and ormsa segregated network [983093983089] At higher dopant concentrationthere may be segregation o the dopant in the polymermatrix which decreases the conductivity Tus motion o charge carriers or localized 1047298uctuations o charged parti-cles in molecular aggregates impedes optical conductivityMoreover there is a weak peak at = 295 eV that can beseen only in the doped samples Tis new peak is attributedto the ormation o charge transer or the surace plasmon

7272019 pva films

httpslidepdfcomreaderfullpva-films 811

983096 Journal o Nanomaterials

0 1 2 3 4 5 6 70

02

04

06

08

1

12

14

16

18

2

Energy photon (eV)

PVA

S1

S2

S3

times10minus16

907317 r

( S m )

F983145983143983157983154983141 983089983090 Real part o the optical conductivity o pure PVA anddoped 1047297lms

0 1 2 3 4 5 6 70

05

1

15

2

25

3

35

Energy photon (eV)

PVA

S1

S2

S3

times10minus13

907317 i

( S m )

F983145983143983157983154983141 983089983091 Imaginary part o the optical conductivity o pure PVAand doped 1047297lms

silver nanoparticles Another result is that by increasingthe concentration o Ag nanoparticles in PVA matrix theimaginary part o optical conductivity decreases

A dielectric sample in an external electric 1047297eld acquiresa nonzero macroscopic dipole moment indicating that thedielectric is polarized under the in1047298uence o the 1047297eld Polar-ization o dielectric material achieves its equilibrium valuenot instantaneously but rather over a period o time [983093983090]Te dielectric relaxation time can be evaluated using

= infin minus 1103925907317 (983094)

Figure 983089983092 shows the dielectric relaxation time as a unc-tion o photon energy or pure PVA polymer and Agnanoparticle doped PVA 1047297lms Te valley at 983090983097983093 eV ordoped samples increases with increasing the concentrationo Ag nanoparticles in the structure o the 1047297lms In otherwords the relaxation time o dipole orientation decreases

2 25 3 35 4 45 5 550

02

04

06

08

1

12

14

16

18

2

Photon energy (eV)

R e

l a x a t

i o n t i m e

( s )

PVA

S1

S2

S3

times10minus12

F983145983143983157983154983141 983089983092 Relaxation time versus photon energy o 1047297lms

Tis is another reason or decreasing the dielectric unctionand increasing the conductivity o 1047297lms with increasing theconcentration o nanoparticles in their structure [983093983091]

Reractive index dispersion is a determinant actor inoptical materials It is a signi1047297cant actor in opticalcommuni-cation andin designingdevices orspectral dispersion[983091983093]Inthe normal dispersion region the reractive index dispersionhasbeen analyzed using thesingleoscillator model developedby theory o Wemple and DiDomenico [983093983092] Tey intro-duced a dispersion-energy parameter which connectsthe coordination number and the charge distribution withineach unit cell

is closely related to chemical bonding

Also they de1047297ned a single oscillator parameter 0 whichis proportional to the energy o oscillator In terms o thisdispersion energy and single oscillator energy 0 thereractive index at requency can be written as

12 minus 1 = 0

minus 10

(ℎ])2 (983095)

Te values o and 0 can be obtained rom the

intercept and slope o the linear part o (2 minus 1)minus1 plot versus

(ℎ]

)2 as is shown in Figure 983089983093 Also dispersion o reractive

index is controlled by the combined effects o and 0 Tecalculated values o the dispersion parameters (0 and )as well as the corresponding optical constant ( = 2) orthe pure PVA 1047297lm and samples 983089 to 983091 are listed in able 983089Te dispersion energy values decreases with increasing theconcentration o Ag nanoparticles in PVA 1047297lms because theanion strength o the dielectric medium has been declinedTereore the PVA polymer host is less willing to keep theelectrons in their outer layers Te single oscillator energy isan average energy gap as pointed out in many reerences [983093983088]Te 0 value o the 1047297lms is related empirically to the lowestindirect bandgap by 0 asymp 103 Tis relation is in goodagreement with the single oscillator model

7272019 pva films

httpslidepdfcomreaderfullpva-films 911

Journal o Nanomaterials 983097

10 105 11 115 12 125 1302

04

06

08

1

12

14

16

PVA

S1

S2

S3

(

n 2

minus

1 ) minus 1

E2 (eV2)

F983145983143983157983154983141 983089983093Plot o (2minus1) versus squared photon energy o pure PVAand doping samples

983137983138983148983141 983089 Dispersion parameters o 1047297lmsSamples 0

PVA 983089983093983094 983090983092983092 983093983089983097 983095983092983097

S983089 983089983092983096 983090983089983097 983093983088983092 983094983088983091

S983090 983089983091983095 983089983096983097 983092983097983095 983092983092983094

S983091 983089983089983097 983089983092983090 983092983096983095 983090983088983093

4 Conclusions

Preparation o silver nanoparticles by laser ablation methodat different 1047298uencies o laser pulse in pure water is investi-gated Te EM analysis revealed that generated nanoparti-

cles in this experimental condition are almost spherical andtheir average size was 983094ndash983089983090 nm and with increasing the laserpulse 1047298uence the size o nanoparticles is decreased Te X-ray diffraction spectrum reveals that the number o crystal-lographic planes at certain angles is increased afer doping Agnanoparticles in the structure o PVA FIR spectrum peakscorrespond to molecular vibrations and chemical bondsindicate the presence o silver in the PVA polymer structureTe optical bandgap energy o the samples is decreasedwith increasing the concentrations o silver nanoparticlesReractive index and dielectric constant are decreased withincreasing the concentration o Ag nanoparticles Increaseo dopant concentration resulted in a decrease in real part

o the optical conductivity because o segregation effectTe reractive index and consequently the related dispersionparameters o PVA and doped PVA have been determinedand explained using the Wemple-DiDomenico model

References

[983089] A Nimrodh Ananth and S Umapathy ldquoOn the optical andthermal properties o in situex situ reduced Ag NPrsquosPVAcomposites and its role as a simple SPR-based protein sensorrdquo Applied Nanoscience vol 983089 no 983090 pp 983096983095ndash983097983094 983090983088983089983089

[983090] G Nesher G Marom and D Avnir ldquoMetal-polymer compos-ites synthesis and characterization o polyaniline and other

polymer at Silver compositionsrdquo Chemistry of Materialsvol983090983088no 983089983091 pp 983092983092983090983093ndash983092983092983091983090 983090983088983088983096

[983091] P-H Wang Y-Z Wu andQ-R ZhuldquoPolymermetal compositeparticles polymer core and metal shellrdquo Journal of MaterialsScience Letters vol 983090983089 no 983090983091 pp 983089983096983090983093ndash983089983096983090983096 983090983088983088983090

[983092] S Clemenson P Alcouffe L David and E Espuche ldquoStructureand morphology o membranes prepared rom polyvinyl alco-hol and silver nitrate in1047298uence o the annealing treatment ando the 1047297lm thicknessrdquo Desalination vol 983090983088983088 no 983089-983091 pp 983092983091983095ndash983092983091983097 983090983088983088983094

[983093] K Akamatsu S akei M Mizuhata et al ldquoPreparation andcharacterization o polymer thin 1047297lms containing silver andsilver sul1047297de nanoparticlesrdquo Tin Solid Films vol 983091983093983097 no 983089 pp983093983093ndash983094983088 983090983088983088983088

[983094] R Zeng M Z Rong M Q Zhang H C Liang and H MZeng ldquoLaser ablation o polymer-based silver nanocompositesrdquo Applied Surface Science vol 983089983096983095 no 983091-983092 pp 983090983091983097ndash983090983092983095 983090983088983088983090

[983095] S Mahendia A K omar and S Kumar ldquoElectrical conduc-tivity and dielectric spectroscopic studies o PVA-Ag nanocom-posite 1047297lmsrdquo Journal of Alloys and Compounds vol 983093983088983096 no 983090pp 983092983088983094ndash983092983089983089 983090983088983089983088

[983096] N Singh and P K Khanna ldquoIn situ synthesis o silver nano-particles in polymethylmethacrylaterdquo Materials Chemistry and Physics vol 983089983088983092 no 983090-983091 pp 983091983094983095ndash983091983095983090 983090983088983088983095

[983097] P K Khanna R Gokhale V V V S Subbarao A K Vish-wanath B K Das and C V V Satyanarayana ldquoPVA stabilizedgold nanoparticles by use o unexplored albeit conventionalreducing agentrdquo Materials Chemistry and Physics vol 983097983090 no983089 pp 983090983090983097ndash983090983091983091 983090983088983088983093

[983089983088] K Akamatsu S akei M Mizuhata et al ldquoPreparation andcharacterization o polymer thin 1047297lms containing silver andsilver sul1047297de nanoparticlesrdquo Tin Solid Films vol 983091983093983097 no 983089 pp983093983093ndash983094983088 983090983088983088983088

[983089983089] I Hussain M Brust A J Papworth and A I Cooper

ldquoPreparationo acrylate-stabilized goldand silver hydrosols andgold-polymer composite 1047297lmsrdquo Langmuir vol 983089983097 no 983089983089 pp983092983096983091983089ndash983092983096983091983093 983090983088983088983091

[983089983090] S A Zavyalov A N Pivkina and J Schoonman ldquoFormationand characterization o metal-polymer nanostructured com-positesrdquo Solid State Ionics vol 983089983092983095 no 983091-983092 pp 983092983089983093ndash983092983089983097 983090983088983088983090

[983089983091] J Lee D Bhattacharyya A J Easteal and J B Metson ldquoProp-erties o nano-ZnOpoly(vinyl alcohol)poly(ethylene oxide)composite thin 1047297lmsrdquo Current Applied Physics vol 983096 no 983089 pp983092983090ndash983092983095 983090983088983088983096

[983089983092] Z Zhong D Wang Y Cui M W Bockrath and C H LieberldquoNanowire crossbar arrays as address decoders or integratednanosystemsrdquo Science vol 983091983088983090 no 983093983094983092983097 pp 983089983091983095983095ndash983089983091983095983097 983090983088983088983091

[983089983093] D S Hopkins D Pekker P M Goldbart and A Bezryadin

ldquoQuantum intererence device made by DNA templating o superconducting nanowiresrdquo Science vol 983091983088983096 no 983093983095983090983097 pp983089983095983094983090ndash983089983095983094983093 983090983088983088983093

[983089983094] S Clemenson D Leonard D Sage L David and E EspucheldquoMetal nanocomposite 1047297lms prepared in Situ rom PVA andsilver nitrate Study o the nanostructuration process andmorphology as a unction o the in Situ routesrdquo Journal of Polymer Science A vol 983092983094 no 983094 pp 983090983088983094983090ndash983090983088983095983089 983090983088983088983096

[983089983095] M K emgire and S S Joshi ldquoOptical and structural studies o silver nanoparticlesrdquo Radiation Physics and Chemistry vol 983095983089no 983093 pp 983089983088983091983097ndash983089983088983092983092 983090983088983088983092

[983089983096] M Zheng M Gu Y Jin and G Jin ldquoOptical properties o silver-dispersed PVP thin 1047297lmrdquo Materials Research Bulletin vol 983091983094no 983093-983094 pp 983096983093983091ndash983096983093983097 983090983088983088983089

7272019 pva films

httpslidepdfcomreaderfullpva-films 1011

983089983088 Journal o Nanomaterials

[983089983097] O L A Monti J Fourkas and D J Nesbitt ldquoDiffraction-limited photogeneration and characterization o silver nanopar-ticlesrdquo Journal of Physical Chemistry B vol 983089983088983096 no 983093 pp 983089983094983088983092ndash983089983094983089983090 983090983088983088983092

[983090983088] K L Kelly E Coronado L L Zhao and G C Schatz ldquoTeopti-cal properties o metal nanoparticles the in1047298uence o sizeshape and dielectric environmentrdquo Journal of Physical Che-

mistry B vol 983089983088983095 no 983091 pp 983094983094983096ndash983094983095983095 983090983088983088983091

[983090983089] H Weickmann J C iller R Tomann and R MulhauptldquoMetallized organoclays as new intermediates or aqueous nan-ohybrid dispersions nanohybrid catalysts and antimicrobialpolymer hybrid nanocompositesrdquo Macromolecular Materialsand Engineering vol 983090983097983088 no 983097 pp 983096983095983093ndash983096983096983091 983090983088983088983093

[983090983090] U Keirbeg and M Vollmer Optical Properties of Metal Clusters vol 983090983093 o Springer Series in Material Science 983089983097983097983093

[983090983091] S Chen and J M Sommers ldquoAlkanethiolate-protected coppernanoparticles spectroscopy electrochemistry and solid-statemorphological evolutionrdquo Journal of Physical Chemistry B vol983089983088983093 no 983091983095 pp 983096983096983089983094ndash983096983096983090983088 983090983088983088983089

[983090983092] A A Scalisi G Compagnini L DrsquoUrso and O Puglisi ldquoNon-linearopticalactivity in Ag-SiO

2 nanocomposite thin 1047297lms with

different silver concentrationrdquo Applied Surface Science vol 983090983090983094no 983089ndash983091 pp 983090983091983095ndash983090983092983089 983090983088983088983092

[983090983093] G Yang W Wang Y Zhou H Lu G Yang and Z Chen ldquoLin-ear and nonlinear optical properties o Ag nanoclusterBaiO3

composite 1047297lmsrdquo Applied Physics Letters vol 983096983089 no 983090983089 pp983091983097983094983097ndash983091983097983095983089 983090983088983088983090

[983090983094] H B Liao R F Xiao H Wang K S Wong and G K L WongldquoLarge third-order optical nonlinearity in AuiO2 composite1047297lms measured on a emtosecond time scalerdquo Applied PhysicsLetters vol 983095983090 no 983089983093 pp 983089983096983089983095ndash983089983096983089983097 983089983097983097983096

[983090983095] A K Sarychev D J Bergman and Y Yagil ldquoTeory o theoptical and microwave properties o metal-dielectric 1047297lmsrdquoPhysical Review B vol 983093983089 no 983096 pp 983093983091983094983094ndash983093983091983096983093 983089983097983097983093

[983090983096] G Mie ldquoBeitrage zur Optik truber Medien speziell kolloidalerMetallosungenrdquo Annalen der Physik vol 983091983091983088 pp 983091983095983095ndash983092983092983093 983089983097983088983096

[983090983097] R Gans ldquoUber die Form ultramikroskopischer Silberteilchenrdquo Annalen der Physik vol 983091983093983090 no 983089983088 pp 983090983095983088ndash983090983096983092 983089983097983089983093

[983091983088] S Link and M A El-Sayed ldquoSpectral properties and relaxationdynamics o surace plasmon electronic oscillations in gold andsilver nanodots and nanorodsrdquo Journal of Physical Chemistry B vol 983089983088983091 no 983092983088 pp 983096983092983089983088ndash983096983092983090983094 983089983097983097983097

[983091983089] G Fussell J Tomas J Scanlon A Lowman and M Mar-colongo ldquoTe effect o protein-ree versus protein-containingmedium on the mechanical properties and uptake o ions o PVAPVP hydrogelsrdquo Journalof BiomaterialsScience vol983089983094 no983092 pp 983092983096983097ndash983093983088983091 983090983088983088983093

[983091983090] suji Mizuki S Ozono and M suji ldquoLaser-induced sil-

ver nanocrystal ormation in polyvinylpyrrolidone solutionsrdquo Journal of Photochemistry and Photobiology A vol 983090983088983094 no 983090-983091pp 983089983091983092ndash983089983091983097 983090983088983088983097

[983091983091] J-P Sylvestre S Poulin A V Kabashin E Sacher M Meunierand J H Luong ldquoSurace chemistry o gold nanoparticlesproduced by laser ablation in aqueous mediardquo Journal of Physical Chemistry B vol 983089983088983096 no 983092983091 pp 983089983094983096983094983092ndash983089983094983096983094983097 983090983088983088983092

[983091983092] A Gautam and S Ram ldquoPreparation and thermomechanicalproperties o Ag-PVA nanocomposite 1047297lmsrdquo Materials Chem-istry and Physics vol 983089983089983097 no 983089-983090 pp 983090983094983094ndash983090983095983089 983090983088983089983088

[983091983093] I Saini J Rozra N Chandak S Aggarwal P K Sharmaand A Sharma ldquoailoring o electrical optical and structuralproperties o PVA by addition o Ag nanoparticlesrdquo MaterChem Phys vol 983089983091983097 pp 983096983088983090ndash983096983089983088 983090983088983089983091

[983091983094] S Mahendia A K omar and S Kumar ldquoNano-Ag dopinginduced changes in optical and electrical behaviour o PVA1047297lmsrdquo Materials Science and Engineering B vol 983089983095983094 no 983095 pp983093983091983088ndash983093983091983092 983090983088983089983089

[983091983095] M Abdelaziz and E M Abdelrazek ldquoEffect o dopant mixtureon structural optical and electron spin resonance properties o polyvinyl alcoholrdquo Physica B vol 983091983097983088 no 983089-983090 pp 983089ndash983097 983090983088983088983095

[983091983096] B Suo X Su J Wu D Chen A Wang and Z Guo ldquoPoly (vinyl alcohol) thin 1047297lm 1047297lled with CdSe-ZnS quantum dotsabrication characterization and optical propertiesrdquo MaterialsChemistry and Physics vol 983089983089983097 no 983089-983090 pp 983090983091983095ndash983090983092983090 983090983088983089983088

[983091983097] B Karthikeyan ldquoSpectroscopic studies on Ag-polyvinyl alcoholnanocomposite 1047297lmsrdquo Physica B vol 983091983094983092 no 983089ndash983092 pp 983091983090983096ndash983091983091983090983090983088983088983093

[983092983088] A S Kutsenko and V M Granchak ldquoPhotochemical synthesiso silver nanoparticles in polyvinyl alcohol matricesrdquo Teoreti-cal and Experimental Chemistry vol 983092983093no 983093 pp 983091983089983091ndash983091983089983096983090983088983088983097

[983092983089] C U Devi A K Sharma and V V R N Rao ldquoElectrical andoptical properties o pure and silver nitrate-doped polyvinylalcohol 1047297lmsrdquo Materials Letters vol 983093983094 no 983091 pp 983089983094983095ndash983089983095983092 983090983088983088983090

[983092983090] B G Streetman Solid State Electronic Devices Prentice HallNew Jersey NJ USA 983091rd edition 983089983097983097983088

[983092983091] J auc and R Grigorovici ldquoOptical properties and electronicstructure o amorphous germaniumrdquo Physica Status Solidi (B) vol 983089983093 no 983090 pp 983094983090983095ndash983094983091983095 983089983097983094983094

[983092983092] J Rozra I Saini A Sharma et al ldquoCu nanoparticles inducedstructural optical and electrical modi1047297cation in PVArdquo Materi-als Chemistry and Physics vol 983089983091983092 no 983090-983091 pp 983089983089983090983089ndash983089983089983090983094 983090983088983089983090

[983092983093] M Abdelaziz ldquoCerium (III) doping effects on optical andthermal properties o PVA 1047297lmsrdquo Physica B vol 983092983088983094 no 983094-983095pp 983089983091983088983088ndash983089983091983088983095 983090983088983089983089

[983092983094] C Kittle Introduction to Solid State Physics vol 983092983088983093 John Wiley amp Sons New York NY USA 983089983097983095983089

[983092983095] J D Jackson Classical Electrodynamics John Wiley amp Sons 983091rdedition 983089983097983097983097

[983092983096] M S Dresselhaus Solid State Physics Part II Optical Propertiesof Solids vol 983094 983090983088983088983089

[983092983097] J N Hodgson Optical Absorption and Dispersion in Solids Chapman amp Hall London UK 983089983097983095983089

[983093983088] Y Caglar S Ilican and M Caglar ldquoSingle-oscillator modeland determination o optical constants o spray pyrolyzedamorphous SnO2 thin 1047297lmsrdquo European Physical Journal B vol983093983096 no 983091 pp 983090983093983089ndash983090983093983094 983090983088983088983095

[983093983089] Y Seok Kim Electrical Conductivity of Segregated NetworkPolymer Nanoposites vol 983089983091983095 983090983088983088983095

[983093983090] Y Feldman A Puzenko and Y Ryabov ldquoDielectric relaxationphenomena in complex materialsrdquo in Advances in Chemical

Physics vol 983089983091983091 pp 983089ndash983089983090983093 Department o Applied Physics TeHebrew University o Jerusalem Jerusalem Israel 983090983088983088983094

[983093983091] S Mahendia A K omar R P Chahal P Goyal and S KumarldquoOptical and structural properties o poly(vinyl alcohol) 1047297lmsembedded with citrate-stabilized gold nanoparticlesrdquo Journal of Physics D vol 983092983092 no 983090983088 Article ID 983090983088983093983089983088983093 983090983088983089983089

[983093983092] S H Wemple and M DiDomenico ldquoBehavior o the electronicdielectric constant in covalent and ionic materialsrdquo Physical Review B vol 983091 no 983092 pp 983089983091983091983096ndash983089983091983093983089 983089983097983095983089

7272019 pva films

httpslidepdfcomreaderfullpva-films 1111

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2013Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The ScientifcWorld Journal

Impact Factor 1730

28 Days Fast Track Peer Review

All Subject Areas of Science

Submit at httpwwwtswjcom

7272019 pva films

httpslidepdfcomreaderfullpva-films 711

Journal o Nanomaterials 983095

0 1 2 3 4 5 6 70

1

2

3

4

5

6

7

8

Photon energy (eV)

E x t i n c t i o

n c o e

ffi c i e n t

PVA

S1

S2

S3

times10minus4

F983145983143983157983154983141 983097 Te extinction coefficient spectrum o 1047297lms

0 1 2 3 4 5 6 715

2

25

3

35

4

Photon energy (eV)

PVA

S1

S2

S3

1103925 r

F983145983143983157983154983141 983089983088 Real part o the dielectric constant o pure PVA and Agnanoparticle doped 1047297lms

Te real part o dielectric constant is related to the disper-sion In order to explain the dispersion it is necessary to takeinto account the actual motion o the electrons in the opticalmedium through which the light is traveling Te imaginary part represents the dissipative rate o electromagnetic wavepropagation in the medium Te real and imaginary partsdependences on photon energy o samples are shown in

Figures 983089983088 and 983089983089 respectively It can be concluded that 1103925is larger than 907317 because it mainly depends on 2 Withincreasing the amount o silver nanoparticles in PVA the realpart o dielectric constant is decreased It is due to decreaseo the dielectric property o 1047297lms because o Ag nanoparticlesmetal lattice in the host PVA polymer matrix Te normaldispersion is associated with an increase in Re() with andanomalous dispersion is associated with the reverse mecha-nism Normal dispersion is occurred everywhere expect inthe neighborhood o the resonance requency In this regionthe anomalous dispersion is appreciable Since a positiveimaginary part to 907317 represents dissipation o energy rom theelectromagnetic wave into the medium the regions where

907317

0 1 2 3 4 5 6 70

05

1

15

2

25

Photon energy (eV)

PVA

S1

S2

S3

times10minus3

1103925 i

F983145983143983157983154983141 983089983089 Imaginary part o the dielectric unction o 1047297lms

is large are called regions o resonant absorption [983092983095] Tepeak that appears in Figure 983089983089 at = 295 eV shows theplasmonic absorption

Te complex dielectric unction and complex opticalconductivity are introduced through Maxwellrsquos equationsTe interband transitions have threshold energy at the energy gap Tat is we expect the requency dependence o thereal part o the conductivity 1103925() due to an interbandtransition to exhibit a threshold or an allowed electronictransition [983092983096] In interband transition real 1103925 and imaginary 907317 components o optical conductivity are described as [983092983096ndash983093983088]

1103925 = 9073170907317 = 11039250 (983093)

where is the angular requency o electromagnetic wave and0 is the ree space dielectric constant Te real and imaginary parts o the optical conductivity dependence on the photonenergy are shown in Figures 983089983090 and 983089983091 respectively

Te real optical conductivity in bandgap energy regionafer doping the Ag-nanoparticles in PVA polymer decreasesIt can be due to the segregation effect [983092983089 983093983089] Te segregatedeffect is the dispersion o metallic particles restricted by thepresence o much larger polymeric particles Te observedeffect o Ag nanoparticles on the optical conductivity and

conduction behavior o PVA 1047297lms can be explained on thebasis o charge transer complex ormation involving PVAmolecules and the dopant When PVA polymer is mixedwith Ag nanoparticles as a result the 1047297ller is pushed intointerstitial space between the polymer particles and ormsa segregated network [983093983089] At higher dopant concentrationthere may be segregation o the dopant in the polymermatrix which decreases the conductivity Tus motion o charge carriers or localized 1047298uctuations o charged parti-cles in molecular aggregates impedes optical conductivityMoreover there is a weak peak at = 295 eV that can beseen only in the doped samples Tis new peak is attributedto the ormation o charge transer or the surace plasmon

7272019 pva films

httpslidepdfcomreaderfullpva-films 811

983096 Journal o Nanomaterials

0 1 2 3 4 5 6 70

02

04

06

08

1

12

14

16

18

2

Energy photon (eV)

PVA

S1

S2

S3

times10minus16

907317 r

( S m )

F983145983143983157983154983141 983089983090 Real part o the optical conductivity o pure PVA anddoped 1047297lms

0 1 2 3 4 5 6 70

05

1

15

2

25

3

35

Energy photon (eV)

PVA

S1

S2

S3

times10minus13

907317 i

( S m )

F983145983143983157983154983141 983089983091 Imaginary part o the optical conductivity o pure PVAand doped 1047297lms

silver nanoparticles Another result is that by increasingthe concentration o Ag nanoparticles in PVA matrix theimaginary part o optical conductivity decreases

A dielectric sample in an external electric 1047297eld acquiresa nonzero macroscopic dipole moment indicating that thedielectric is polarized under the in1047298uence o the 1047297eld Polar-ization o dielectric material achieves its equilibrium valuenot instantaneously but rather over a period o time [983093983090]Te dielectric relaxation time can be evaluated using

= infin minus 1103925907317 (983094)

Figure 983089983092 shows the dielectric relaxation time as a unc-tion o photon energy or pure PVA polymer and Agnanoparticle doped PVA 1047297lms Te valley at 983090983097983093 eV ordoped samples increases with increasing the concentrationo Ag nanoparticles in the structure o the 1047297lms In otherwords the relaxation time o dipole orientation decreases

2 25 3 35 4 45 5 550

02

04

06

08

1

12

14

16

18

2

Photon energy (eV)

R e

l a x a t

i o n t i m e

( s )

PVA

S1

S2

S3

times10minus12

F983145983143983157983154983141 983089983092 Relaxation time versus photon energy o 1047297lms

Tis is another reason or decreasing the dielectric unctionand increasing the conductivity o 1047297lms with increasing theconcentration o nanoparticles in their structure [983093983091]

Reractive index dispersion is a determinant actor inoptical materials It is a signi1047297cant actor in opticalcommuni-cation andin designingdevices orspectral dispersion[983091983093]Inthe normal dispersion region the reractive index dispersionhasbeen analyzed using thesingleoscillator model developedby theory o Wemple and DiDomenico [983093983092] Tey intro-duced a dispersion-energy parameter which connectsthe coordination number and the charge distribution withineach unit cell

is closely related to chemical bonding

Also they de1047297ned a single oscillator parameter 0 whichis proportional to the energy o oscillator In terms o thisdispersion energy and single oscillator energy 0 thereractive index at requency can be written as

12 minus 1 = 0

minus 10

(ℎ])2 (983095)

Te values o and 0 can be obtained rom the

intercept and slope o the linear part o (2 minus 1)minus1 plot versus

(ℎ]

)2 as is shown in Figure 983089983093 Also dispersion o reractive

index is controlled by the combined effects o and 0 Tecalculated values o the dispersion parameters (0 and )as well as the corresponding optical constant ( = 2) orthe pure PVA 1047297lm and samples 983089 to 983091 are listed in able 983089Te dispersion energy values decreases with increasing theconcentration o Ag nanoparticles in PVA 1047297lms because theanion strength o the dielectric medium has been declinedTereore the PVA polymer host is less willing to keep theelectrons in their outer layers Te single oscillator energy isan average energy gap as pointed out in many reerences [983093983088]Te 0 value o the 1047297lms is related empirically to the lowestindirect bandgap by 0 asymp 103 Tis relation is in goodagreement with the single oscillator model

7272019 pva films

httpslidepdfcomreaderfullpva-films 911

Journal o Nanomaterials 983097

10 105 11 115 12 125 1302

04

06

08

1

12

14

16

PVA

S1

S2

S3

(

n 2

minus

1 ) minus 1

E2 (eV2)

F983145983143983157983154983141 983089983093Plot o (2minus1) versus squared photon energy o pure PVAand doping samples

983137983138983148983141 983089 Dispersion parameters o 1047297lmsSamples 0

PVA 983089983093983094 983090983092983092 983093983089983097 983095983092983097

S983089 983089983092983096 983090983089983097 983093983088983092 983094983088983091

S983090 983089983091983095 983089983096983097 983092983097983095 983092983092983094

S983091 983089983089983097 983089983092983090 983092983096983095 983090983088983093

4 Conclusions

Preparation o silver nanoparticles by laser ablation methodat different 1047298uencies o laser pulse in pure water is investi-gated Te EM analysis revealed that generated nanoparti-

cles in this experimental condition are almost spherical andtheir average size was 983094ndash983089983090 nm and with increasing the laserpulse 1047298uence the size o nanoparticles is decreased Te X-ray diffraction spectrum reveals that the number o crystal-lographic planes at certain angles is increased afer doping Agnanoparticles in the structure o PVA FIR spectrum peakscorrespond to molecular vibrations and chemical bondsindicate the presence o silver in the PVA polymer structureTe optical bandgap energy o the samples is decreasedwith increasing the concentrations o silver nanoparticlesReractive index and dielectric constant are decreased withincreasing the concentration o Ag nanoparticles Increaseo dopant concentration resulted in a decrease in real part

o the optical conductivity because o segregation effectTe reractive index and consequently the related dispersionparameters o PVA and doped PVA have been determinedand explained using the Wemple-DiDomenico model

References

[983089] A Nimrodh Ananth and S Umapathy ldquoOn the optical andthermal properties o in situex situ reduced Ag NPrsquosPVAcomposites and its role as a simple SPR-based protein sensorrdquo Applied Nanoscience vol 983089 no 983090 pp 983096983095ndash983097983094 983090983088983089983089

[983090] G Nesher G Marom and D Avnir ldquoMetal-polymer compos-ites synthesis and characterization o polyaniline and other

polymer at Silver compositionsrdquo Chemistry of Materialsvol983090983088no 983089983091 pp 983092983092983090983093ndash983092983092983091983090 983090983088983088983096

[983091] P-H Wang Y-Z Wu andQ-R ZhuldquoPolymermetal compositeparticles polymer core and metal shellrdquo Journal of MaterialsScience Letters vol 983090983089 no 983090983091 pp 983089983096983090983093ndash983089983096983090983096 983090983088983088983090

[983092] S Clemenson P Alcouffe L David and E Espuche ldquoStructureand morphology o membranes prepared rom polyvinyl alco-hol and silver nitrate in1047298uence o the annealing treatment ando the 1047297lm thicknessrdquo Desalination vol 983090983088983088 no 983089-983091 pp 983092983091983095ndash983092983091983097 983090983088983088983094

[983093] K Akamatsu S akei M Mizuhata et al ldquoPreparation andcharacterization o polymer thin 1047297lms containing silver andsilver sul1047297de nanoparticlesrdquo Tin Solid Films vol 983091983093983097 no 983089 pp983093983093ndash983094983088 983090983088983088983088

[983094] R Zeng M Z Rong M Q Zhang H C Liang and H MZeng ldquoLaser ablation o polymer-based silver nanocompositesrdquo Applied Surface Science vol 983089983096983095 no 983091-983092 pp 983090983091983097ndash983090983092983095 983090983088983088983090

[983095] S Mahendia A K omar and S Kumar ldquoElectrical conduc-tivity and dielectric spectroscopic studies o PVA-Ag nanocom-posite 1047297lmsrdquo Journal of Alloys and Compounds vol 983093983088983096 no 983090pp 983092983088983094ndash983092983089983089 983090983088983089983088

[983096] N Singh and P K Khanna ldquoIn situ synthesis o silver nano-particles in polymethylmethacrylaterdquo Materials Chemistry and Physics vol 983089983088983092 no 983090-983091 pp 983091983094983095ndash983091983095983090 983090983088983088983095

[983097] P K Khanna R Gokhale V V V S Subbarao A K Vish-wanath B K Das and C V V Satyanarayana ldquoPVA stabilizedgold nanoparticles by use o unexplored albeit conventionalreducing agentrdquo Materials Chemistry and Physics vol 983097983090 no983089 pp 983090983090983097ndash983090983091983091 983090983088983088983093

[983089983088] K Akamatsu S akei M Mizuhata et al ldquoPreparation andcharacterization o polymer thin 1047297lms containing silver andsilver sul1047297de nanoparticlesrdquo Tin Solid Films vol 983091983093983097 no 983089 pp983093983093ndash983094983088 983090983088983088983088

[983089983089] I Hussain M Brust A J Papworth and A I Cooper

ldquoPreparationo acrylate-stabilized goldand silver hydrosols andgold-polymer composite 1047297lmsrdquo Langmuir vol 983089983097 no 983089983089 pp983092983096983091983089ndash983092983096983091983093 983090983088983088983091

[983089983090] S A Zavyalov A N Pivkina and J Schoonman ldquoFormationand characterization o metal-polymer nanostructured com-positesrdquo Solid State Ionics vol 983089983092983095 no 983091-983092 pp 983092983089983093ndash983092983089983097 983090983088983088983090

[983089983091] J Lee D Bhattacharyya A J Easteal and J B Metson ldquoProp-erties o nano-ZnOpoly(vinyl alcohol)poly(ethylene oxide)composite thin 1047297lmsrdquo Current Applied Physics vol 983096 no 983089 pp983092983090ndash983092983095 983090983088983088983096

[983089983092] Z Zhong D Wang Y Cui M W Bockrath and C H LieberldquoNanowire crossbar arrays as address decoders or integratednanosystemsrdquo Science vol 983091983088983090 no 983093983094983092983097 pp 983089983091983095983095ndash983089983091983095983097 983090983088983088983091

[983089983093] D S Hopkins D Pekker P M Goldbart and A Bezryadin

ldquoQuantum intererence device made by DNA templating o superconducting nanowiresrdquo Science vol 983091983088983096 no 983093983095983090983097 pp983089983095983094983090ndash983089983095983094983093 983090983088983088983093

[983089983094] S Clemenson D Leonard D Sage L David and E EspucheldquoMetal nanocomposite 1047297lms prepared in Situ rom PVA andsilver nitrate Study o the nanostructuration process andmorphology as a unction o the in Situ routesrdquo Journal of Polymer Science A vol 983092983094 no 983094 pp 983090983088983094983090ndash983090983088983095983089 983090983088983088983096

[983089983095] M K emgire and S S Joshi ldquoOptical and structural studies o silver nanoparticlesrdquo Radiation Physics and Chemistry vol 983095983089no 983093 pp 983089983088983091983097ndash983089983088983092983092 983090983088983088983092

[983089983096] M Zheng M Gu Y Jin and G Jin ldquoOptical properties o silver-dispersed PVP thin 1047297lmrdquo Materials Research Bulletin vol 983091983094no 983093-983094 pp 983096983093983091ndash983096983093983097 983090983088983088983089

7272019 pva films

httpslidepdfcomreaderfullpva-films 1011

983089983088 Journal o Nanomaterials

[983089983097] O L A Monti J Fourkas and D J Nesbitt ldquoDiffraction-limited photogeneration and characterization o silver nanopar-ticlesrdquo Journal of Physical Chemistry B vol 983089983088983096 no 983093 pp 983089983094983088983092ndash983089983094983089983090 983090983088983088983092

[983090983088] K L Kelly E Coronado L L Zhao and G C Schatz ldquoTeopti-cal properties o metal nanoparticles the in1047298uence o sizeshape and dielectric environmentrdquo Journal of Physical Che-

mistry B vol 983089983088983095 no 983091 pp 983094983094983096ndash983094983095983095 983090983088983088983091

[983090983089] H Weickmann J C iller R Tomann and R MulhauptldquoMetallized organoclays as new intermediates or aqueous nan-ohybrid dispersions nanohybrid catalysts and antimicrobialpolymer hybrid nanocompositesrdquo Macromolecular Materialsand Engineering vol 983090983097983088 no 983097 pp 983096983095983093ndash983096983096983091 983090983088983088983093

[983090983090] U Keirbeg and M Vollmer Optical Properties of Metal Clusters vol 983090983093 o Springer Series in Material Science 983089983097983097983093

[983090983091] S Chen and J M Sommers ldquoAlkanethiolate-protected coppernanoparticles spectroscopy electrochemistry and solid-statemorphological evolutionrdquo Journal of Physical Chemistry B vol983089983088983093 no 983091983095 pp 983096983096983089983094ndash983096983096983090983088 983090983088983088983089

[983090983092] A A Scalisi G Compagnini L DrsquoUrso and O Puglisi ldquoNon-linearopticalactivity in Ag-SiO

2 nanocomposite thin 1047297lms with

different silver concentrationrdquo Applied Surface Science vol 983090983090983094no 983089ndash983091 pp 983090983091983095ndash983090983092983089 983090983088983088983092

[983090983093] G Yang W Wang Y Zhou H Lu G Yang and Z Chen ldquoLin-ear and nonlinear optical properties o Ag nanoclusterBaiO3

composite 1047297lmsrdquo Applied Physics Letters vol 983096983089 no 983090983089 pp983091983097983094983097ndash983091983097983095983089 983090983088983088983090

[983090983094] H B Liao R F Xiao H Wang K S Wong and G K L WongldquoLarge third-order optical nonlinearity in AuiO2 composite1047297lms measured on a emtosecond time scalerdquo Applied PhysicsLetters vol 983095983090 no 983089983093 pp 983089983096983089983095ndash983089983096983089983097 983089983097983097983096

[983090983095] A K Sarychev D J Bergman and Y Yagil ldquoTeory o theoptical and microwave properties o metal-dielectric 1047297lmsrdquoPhysical Review B vol 983093983089 no 983096 pp 983093983091983094983094ndash983093983091983096983093 983089983097983097983093

[983090983096] G Mie ldquoBeitrage zur Optik truber Medien speziell kolloidalerMetallosungenrdquo Annalen der Physik vol 983091983091983088 pp 983091983095983095ndash983092983092983093 983089983097983088983096

[983090983097] R Gans ldquoUber die Form ultramikroskopischer Silberteilchenrdquo Annalen der Physik vol 983091983093983090 no 983089983088 pp 983090983095983088ndash983090983096983092 983089983097983089983093

[983091983088] S Link and M A El-Sayed ldquoSpectral properties and relaxationdynamics o surace plasmon electronic oscillations in gold andsilver nanodots and nanorodsrdquo Journal of Physical Chemistry B vol 983089983088983091 no 983092983088 pp 983096983092983089983088ndash983096983092983090983094 983089983097983097983097

[983091983089] G Fussell J Tomas J Scanlon A Lowman and M Mar-colongo ldquoTe effect o protein-ree versus protein-containingmedium on the mechanical properties and uptake o ions o PVAPVP hydrogelsrdquo Journalof BiomaterialsScience vol983089983094 no983092 pp 983092983096983097ndash983093983088983091 983090983088983088983093

[983091983090] suji Mizuki S Ozono and M suji ldquoLaser-induced sil-

ver nanocrystal ormation in polyvinylpyrrolidone solutionsrdquo Journal of Photochemistry and Photobiology A vol 983090983088983094 no 983090-983091pp 983089983091983092ndash983089983091983097 983090983088983088983097

[983091983091] J-P Sylvestre S Poulin A V Kabashin E Sacher M Meunierand J H Luong ldquoSurace chemistry o gold nanoparticlesproduced by laser ablation in aqueous mediardquo Journal of Physical Chemistry B vol 983089983088983096 no 983092983091 pp 983089983094983096983094983092ndash983089983094983096983094983097 983090983088983088983092

[983091983092] A Gautam and S Ram ldquoPreparation and thermomechanicalproperties o Ag-PVA nanocomposite 1047297lmsrdquo Materials Chem-istry and Physics vol 983089983089983097 no 983089-983090 pp 983090983094983094ndash983090983095983089 983090983088983089983088

[983091983093] I Saini J Rozra N Chandak S Aggarwal P K Sharmaand A Sharma ldquoailoring o electrical optical and structuralproperties o PVA by addition o Ag nanoparticlesrdquo MaterChem Phys vol 983089983091983097 pp 983096983088983090ndash983096983089983088 983090983088983089983091

[983091983094] S Mahendia A K omar and S Kumar ldquoNano-Ag dopinginduced changes in optical and electrical behaviour o PVA1047297lmsrdquo Materials Science and Engineering B vol 983089983095983094 no 983095 pp983093983091983088ndash983093983091983092 983090983088983089983089

[983091983095] M Abdelaziz and E M Abdelrazek ldquoEffect o dopant mixtureon structural optical and electron spin resonance properties o polyvinyl alcoholrdquo Physica B vol 983091983097983088 no 983089-983090 pp 983089ndash983097 983090983088983088983095

[983091983096] B Suo X Su J Wu D Chen A Wang and Z Guo ldquoPoly (vinyl alcohol) thin 1047297lm 1047297lled with CdSe-ZnS quantum dotsabrication characterization and optical propertiesrdquo MaterialsChemistry and Physics vol 983089983089983097 no 983089-983090 pp 983090983091983095ndash983090983092983090 983090983088983089983088

[983091983097] B Karthikeyan ldquoSpectroscopic studies on Ag-polyvinyl alcoholnanocomposite 1047297lmsrdquo Physica B vol 983091983094983092 no 983089ndash983092 pp 983091983090983096ndash983091983091983090983090983088983088983093

[983092983088] A S Kutsenko and V M Granchak ldquoPhotochemical synthesiso silver nanoparticles in polyvinyl alcohol matricesrdquo Teoreti-cal and Experimental Chemistry vol 983092983093no 983093 pp 983091983089983091ndash983091983089983096983090983088983088983097

[983092983089] C U Devi A K Sharma and V V R N Rao ldquoElectrical andoptical properties o pure and silver nitrate-doped polyvinylalcohol 1047297lmsrdquo Materials Letters vol 983093983094 no 983091 pp 983089983094983095ndash983089983095983092 983090983088983088983090

[983092983090] B G Streetman Solid State Electronic Devices Prentice HallNew Jersey NJ USA 983091rd edition 983089983097983097983088

[983092983091] J auc and R Grigorovici ldquoOptical properties and electronicstructure o amorphous germaniumrdquo Physica Status Solidi (B) vol 983089983093 no 983090 pp 983094983090983095ndash983094983091983095 983089983097983094983094

[983092983092] J Rozra I Saini A Sharma et al ldquoCu nanoparticles inducedstructural optical and electrical modi1047297cation in PVArdquo Materi-als Chemistry and Physics vol 983089983091983092 no 983090-983091 pp 983089983089983090983089ndash983089983089983090983094 983090983088983089983090

[983092983093] M Abdelaziz ldquoCerium (III) doping effects on optical andthermal properties o PVA 1047297lmsrdquo Physica B vol 983092983088983094 no 983094-983095pp 983089983091983088983088ndash983089983091983088983095 983090983088983089983089

[983092983094] C Kittle Introduction to Solid State Physics vol 983092983088983093 John Wiley amp Sons New York NY USA 983089983097983095983089

[983092983095] J D Jackson Classical Electrodynamics John Wiley amp Sons 983091rdedition 983089983097983097983097

[983092983096] M S Dresselhaus Solid State Physics Part II Optical Propertiesof Solids vol 983094 983090983088983088983089

[983092983097] J N Hodgson Optical Absorption and Dispersion in Solids Chapman amp Hall London UK 983089983097983095983089

[983093983088] Y Caglar S Ilican and M Caglar ldquoSingle-oscillator modeland determination o optical constants o spray pyrolyzedamorphous SnO2 thin 1047297lmsrdquo European Physical Journal B vol983093983096 no 983091 pp 983090983093983089ndash983090983093983094 983090983088983088983095

[983093983089] Y Seok Kim Electrical Conductivity of Segregated NetworkPolymer Nanoposites vol 983089983091983095 983090983088983088983095

[983093983090] Y Feldman A Puzenko and Y Ryabov ldquoDielectric relaxationphenomena in complex materialsrdquo in Advances in Chemical

Physics vol 983089983091983091 pp 983089ndash983089983090983093 Department o Applied Physics TeHebrew University o Jerusalem Jerusalem Israel 983090983088983088983094

[983093983091] S Mahendia A K omar R P Chahal P Goyal and S KumarldquoOptical and structural properties o poly(vinyl alcohol) 1047297lmsembedded with citrate-stabilized gold nanoparticlesrdquo Journal of Physics D vol 983092983092 no 983090983088 Article ID 983090983088983093983089983088983093 983090983088983089983089

[983093983092] S H Wemple and M DiDomenico ldquoBehavior o the electronicdielectric constant in covalent and ionic materialsrdquo Physical Review B vol 983091 no 983092 pp 983089983091983091983096ndash983089983091983093983089 983089983097983095983089

7272019 pva films

httpslidepdfcomreaderfullpva-films 1111

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2013Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The ScientifcWorld Journal

Impact Factor 1730

28 Days Fast Track Peer Review

All Subject Areas of Science

Submit at httpwwwtswjcom

7272019 pva films

httpslidepdfcomreaderfullpva-films 811

983096 Journal o Nanomaterials

0 1 2 3 4 5 6 70

02

04

06

08

1

12

14

16

18

2

Energy photon (eV)

PVA

S1

S2

S3

times10minus16

907317 r

( S m )

F983145983143983157983154983141 983089983090 Real part o the optical conductivity o pure PVA anddoped 1047297lms

0 1 2 3 4 5 6 70

05

1

15

2

25

3

35

Energy photon (eV)

PVA

S1

S2

S3

times10minus13

907317 i

( S m )

F983145983143983157983154983141 983089983091 Imaginary part o the optical conductivity o pure PVAand doped 1047297lms

silver nanoparticles Another result is that by increasingthe concentration o Ag nanoparticles in PVA matrix theimaginary part o optical conductivity decreases

A dielectric sample in an external electric 1047297eld acquiresa nonzero macroscopic dipole moment indicating that thedielectric is polarized under the in1047298uence o the 1047297eld Polar-ization o dielectric material achieves its equilibrium valuenot instantaneously but rather over a period o time [983093983090]Te dielectric relaxation time can be evaluated using

= infin minus 1103925907317 (983094)

Figure 983089983092 shows the dielectric relaxation time as a unc-tion o photon energy or pure PVA polymer and Agnanoparticle doped PVA 1047297lms Te valley at 983090983097983093 eV ordoped samples increases with increasing the concentrationo Ag nanoparticles in the structure o the 1047297lms In otherwords the relaxation time o dipole orientation decreases

2 25 3 35 4 45 5 550

02

04

06

08

1

12

14

16

18

2

Photon energy (eV)

R e

l a x a t

i o n t i m e

( s )

PVA

S1

S2

S3

times10minus12

F983145983143983157983154983141 983089983092 Relaxation time versus photon energy o 1047297lms

Tis is another reason or decreasing the dielectric unctionand increasing the conductivity o 1047297lms with increasing theconcentration o nanoparticles in their structure [983093983091]

Reractive index dispersion is a determinant actor inoptical materials It is a signi1047297cant actor in opticalcommuni-cation andin designingdevices orspectral dispersion[983091983093]Inthe normal dispersion region the reractive index dispersionhasbeen analyzed using thesingleoscillator model developedby theory o Wemple and DiDomenico [983093983092] Tey intro-duced a dispersion-energy parameter which connectsthe coordination number and the charge distribution withineach unit cell

is closely related to chemical bonding

Also they de1047297ned a single oscillator parameter 0 whichis proportional to the energy o oscillator In terms o thisdispersion energy and single oscillator energy 0 thereractive index at requency can be written as

12 minus 1 = 0

minus 10

(ℎ])2 (983095)

Te values o and 0 can be obtained rom the

intercept and slope o the linear part o (2 minus 1)minus1 plot versus

(ℎ]

)2 as is shown in Figure 983089983093 Also dispersion o reractive

index is controlled by the combined effects o and 0 Tecalculated values o the dispersion parameters (0 and )as well as the corresponding optical constant ( = 2) orthe pure PVA 1047297lm and samples 983089 to 983091 are listed in able 983089Te dispersion energy values decreases with increasing theconcentration o Ag nanoparticles in PVA 1047297lms because theanion strength o the dielectric medium has been declinedTereore the PVA polymer host is less willing to keep theelectrons in their outer layers Te single oscillator energy isan average energy gap as pointed out in many reerences [983093983088]Te 0 value o the 1047297lms is related empirically to the lowestindirect bandgap by 0 asymp 103 Tis relation is in goodagreement with the single oscillator model

7272019 pva films

httpslidepdfcomreaderfullpva-films 911

Journal o Nanomaterials 983097

10 105 11 115 12 125 1302

04

06

08

1

12

14

16

PVA

S1

S2

S3

(

n 2

minus

1 ) minus 1

E2 (eV2)

F983145983143983157983154983141 983089983093Plot o (2minus1) versus squared photon energy o pure PVAand doping samples

983137983138983148983141 983089 Dispersion parameters o 1047297lmsSamples 0

PVA 983089983093983094 983090983092983092 983093983089983097 983095983092983097

S983089 983089983092983096 983090983089983097 983093983088983092 983094983088983091

S983090 983089983091983095 983089983096983097 983092983097983095 983092983092983094

S983091 983089983089983097 983089983092983090 983092983096983095 983090983088983093

4 Conclusions

Preparation o silver nanoparticles by laser ablation methodat different 1047298uencies o laser pulse in pure water is investi-gated Te EM analysis revealed that generated nanoparti-

cles in this experimental condition are almost spherical andtheir average size was 983094ndash983089983090 nm and with increasing the laserpulse 1047298uence the size o nanoparticles is decreased Te X-ray diffraction spectrum reveals that the number o crystal-lographic planes at certain angles is increased afer doping Agnanoparticles in the structure o PVA FIR spectrum peakscorrespond to molecular vibrations and chemical bondsindicate the presence o silver in the PVA polymer structureTe optical bandgap energy o the samples is decreasedwith increasing the concentrations o silver nanoparticlesReractive index and dielectric constant are decreased withincreasing the concentration o Ag nanoparticles Increaseo dopant concentration resulted in a decrease in real part

o the optical conductivity because o segregation effectTe reractive index and consequently the related dispersionparameters o PVA and doped PVA have been determinedand explained using the Wemple-DiDomenico model

References

[983089] A Nimrodh Ananth and S Umapathy ldquoOn the optical andthermal properties o in situex situ reduced Ag NPrsquosPVAcomposites and its role as a simple SPR-based protein sensorrdquo Applied Nanoscience vol 983089 no 983090 pp 983096983095ndash983097983094 983090983088983089983089

[983090] G Nesher G Marom and D Avnir ldquoMetal-polymer compos-ites synthesis and characterization o polyaniline and other

polymer at Silver compositionsrdquo Chemistry of Materialsvol983090983088no 983089983091 pp 983092983092983090983093ndash983092983092983091983090 983090983088983088983096

[983091] P-H Wang Y-Z Wu andQ-R ZhuldquoPolymermetal compositeparticles polymer core and metal shellrdquo Journal of MaterialsScience Letters vol 983090983089 no 983090983091 pp 983089983096983090983093ndash983089983096983090983096 983090983088983088983090

[983092] S Clemenson P Alcouffe L David and E Espuche ldquoStructureand morphology o membranes prepared rom polyvinyl alco-hol and silver nitrate in1047298uence o the annealing treatment ando the 1047297lm thicknessrdquo Desalination vol 983090983088983088 no 983089-983091 pp 983092983091983095ndash983092983091983097 983090983088983088983094

[983093] K Akamatsu S akei M Mizuhata et al ldquoPreparation andcharacterization o polymer thin 1047297lms containing silver andsilver sul1047297de nanoparticlesrdquo Tin Solid Films vol 983091983093983097 no 983089 pp983093983093ndash983094983088 983090983088983088983088

[983094] R Zeng M Z Rong M Q Zhang H C Liang and H MZeng ldquoLaser ablation o polymer-based silver nanocompositesrdquo Applied Surface Science vol 983089983096983095 no 983091-983092 pp 983090983091983097ndash983090983092983095 983090983088983088983090

[983095] S Mahendia A K omar and S Kumar ldquoElectrical conduc-tivity and dielectric spectroscopic studies o PVA-Ag nanocom-posite 1047297lmsrdquo Journal of Alloys and Compounds vol 983093983088983096 no 983090pp 983092983088983094ndash983092983089983089 983090983088983089983088

[983096] N Singh and P K Khanna ldquoIn situ synthesis o silver nano-particles in polymethylmethacrylaterdquo Materials Chemistry and Physics vol 983089983088983092 no 983090-983091 pp 983091983094983095ndash983091983095983090 983090983088983088983095

[983097] P K Khanna R Gokhale V V V S Subbarao A K Vish-wanath B K Das and C V V Satyanarayana ldquoPVA stabilizedgold nanoparticles by use o unexplored albeit conventionalreducing agentrdquo Materials Chemistry and Physics vol 983097983090 no983089 pp 983090983090983097ndash983090983091983091 983090983088983088983093

[983089983088] K Akamatsu S akei M Mizuhata et al ldquoPreparation andcharacterization o polymer thin 1047297lms containing silver andsilver sul1047297de nanoparticlesrdquo Tin Solid Films vol 983091983093983097 no 983089 pp983093983093ndash983094983088 983090983088983088983088

[983089983089] I Hussain M Brust A J Papworth and A I Cooper

ldquoPreparationo acrylate-stabilized goldand silver hydrosols andgold-polymer composite 1047297lmsrdquo Langmuir vol 983089983097 no 983089983089 pp983092983096983091983089ndash983092983096983091983093 983090983088983088983091

[983089983090] S A Zavyalov A N Pivkina and J Schoonman ldquoFormationand characterization o metal-polymer nanostructured com-positesrdquo Solid State Ionics vol 983089983092983095 no 983091-983092 pp 983092983089983093ndash983092983089983097 983090983088983088983090

[983089983091] J Lee D Bhattacharyya A J Easteal and J B Metson ldquoProp-erties o nano-ZnOpoly(vinyl alcohol)poly(ethylene oxide)composite thin 1047297lmsrdquo Current Applied Physics vol 983096 no 983089 pp983092983090ndash983092983095 983090983088983088983096

[983089983092] Z Zhong D Wang Y Cui M W Bockrath and C H LieberldquoNanowire crossbar arrays as address decoders or integratednanosystemsrdquo Science vol 983091983088983090 no 983093983094983092983097 pp 983089983091983095983095ndash983089983091983095983097 983090983088983088983091

[983089983093] D S Hopkins D Pekker P M Goldbart and A Bezryadin

ldquoQuantum intererence device made by DNA templating o superconducting nanowiresrdquo Science vol 983091983088983096 no 983093983095983090983097 pp983089983095983094983090ndash983089983095983094983093 983090983088983088983093

[983089983094] S Clemenson D Leonard D Sage L David and E EspucheldquoMetal nanocomposite 1047297lms prepared in Situ rom PVA andsilver nitrate Study o the nanostructuration process andmorphology as a unction o the in Situ routesrdquo Journal of Polymer Science A vol 983092983094 no 983094 pp 983090983088983094983090ndash983090983088983095983089 983090983088983088983096

[983089983095] M K emgire and S S Joshi ldquoOptical and structural studies o silver nanoparticlesrdquo Radiation Physics and Chemistry vol 983095983089no 983093 pp 983089983088983091983097ndash983089983088983092983092 983090983088983088983092

[983089983096] M Zheng M Gu Y Jin and G Jin ldquoOptical properties o silver-dispersed PVP thin 1047297lmrdquo Materials Research Bulletin vol 983091983094no 983093-983094 pp 983096983093983091ndash983096983093983097 983090983088983088983089

7272019 pva films

httpslidepdfcomreaderfullpva-films 1011

983089983088 Journal o Nanomaterials

[983089983097] O L A Monti J Fourkas and D J Nesbitt ldquoDiffraction-limited photogeneration and characterization o silver nanopar-ticlesrdquo Journal of Physical Chemistry B vol 983089983088983096 no 983093 pp 983089983094983088983092ndash983089983094983089983090 983090983088983088983092

[983090983088] K L Kelly E Coronado L L Zhao and G C Schatz ldquoTeopti-cal properties o metal nanoparticles the in1047298uence o sizeshape and dielectric environmentrdquo Journal of Physical Che-

mistry B vol 983089983088983095 no 983091 pp 983094983094983096ndash983094983095983095 983090983088983088983091

[983090983089] H Weickmann J C iller R Tomann and R MulhauptldquoMetallized organoclays as new intermediates or aqueous nan-ohybrid dispersions nanohybrid catalysts and antimicrobialpolymer hybrid nanocompositesrdquo Macromolecular Materialsand Engineering vol 983090983097983088 no 983097 pp 983096983095983093ndash983096983096983091 983090983088983088983093

[983090983090] U Keirbeg and M Vollmer Optical Properties of Metal Clusters vol 983090983093 o Springer Series in Material Science 983089983097983097983093

[983090983091] S Chen and J M Sommers ldquoAlkanethiolate-protected coppernanoparticles spectroscopy electrochemistry and solid-statemorphological evolutionrdquo Journal of Physical Chemistry B vol983089983088983093 no 983091983095 pp 983096983096983089983094ndash983096983096983090983088 983090983088983088983089

[983090983092] A A Scalisi G Compagnini L DrsquoUrso and O Puglisi ldquoNon-linearopticalactivity in Ag-SiO

2 nanocomposite thin 1047297lms with

different silver concentrationrdquo Applied Surface Science vol 983090983090983094no 983089ndash983091 pp 983090983091983095ndash983090983092983089 983090983088983088983092

[983090983093] G Yang W Wang Y Zhou H Lu G Yang and Z Chen ldquoLin-ear and nonlinear optical properties o Ag nanoclusterBaiO3

composite 1047297lmsrdquo Applied Physics Letters vol 983096983089 no 983090983089 pp983091983097983094983097ndash983091983097983095983089 983090983088983088983090

[983090983094] H B Liao R F Xiao H Wang K S Wong and G K L WongldquoLarge third-order optical nonlinearity in AuiO2 composite1047297lms measured on a emtosecond time scalerdquo Applied PhysicsLetters vol 983095983090 no 983089983093 pp 983089983096983089983095ndash983089983096983089983097 983089983097983097983096

[983090983095] A K Sarychev D J Bergman and Y Yagil ldquoTeory o theoptical and microwave properties o metal-dielectric 1047297lmsrdquoPhysical Review B vol 983093983089 no 983096 pp 983093983091983094983094ndash983093983091983096983093 983089983097983097983093

[983090983096] G Mie ldquoBeitrage zur Optik truber Medien speziell kolloidalerMetallosungenrdquo Annalen der Physik vol 983091983091983088 pp 983091983095983095ndash983092983092983093 983089983097983088983096

[983090983097] R Gans ldquoUber die Form ultramikroskopischer Silberteilchenrdquo Annalen der Physik vol 983091983093983090 no 983089983088 pp 983090983095983088ndash983090983096983092 983089983097983089983093

[983091983088] S Link and M A El-Sayed ldquoSpectral properties and relaxationdynamics o surace plasmon electronic oscillations in gold andsilver nanodots and nanorodsrdquo Journal of Physical Chemistry B vol 983089983088983091 no 983092983088 pp 983096983092983089983088ndash983096983092983090983094 983089983097983097983097

[983091983089] G Fussell J Tomas J Scanlon A Lowman and M Mar-colongo ldquoTe effect o protein-ree versus protein-containingmedium on the mechanical properties and uptake o ions o PVAPVP hydrogelsrdquo Journalof BiomaterialsScience vol983089983094 no983092 pp 983092983096983097ndash983093983088983091 983090983088983088983093

[983091983090] suji Mizuki S Ozono and M suji ldquoLaser-induced sil-

ver nanocrystal ormation in polyvinylpyrrolidone solutionsrdquo Journal of Photochemistry and Photobiology A vol 983090983088983094 no 983090-983091pp 983089983091983092ndash983089983091983097 983090983088983088983097

[983091983091] J-P Sylvestre S Poulin A V Kabashin E Sacher M Meunierand J H Luong ldquoSurace chemistry o gold nanoparticlesproduced by laser ablation in aqueous mediardquo Journal of Physical Chemistry B vol 983089983088983096 no 983092983091 pp 983089983094983096983094983092ndash983089983094983096983094983097 983090983088983088983092

[983091983092] A Gautam and S Ram ldquoPreparation and thermomechanicalproperties o Ag-PVA nanocomposite 1047297lmsrdquo Materials Chem-istry and Physics vol 983089983089983097 no 983089-983090 pp 983090983094983094ndash983090983095983089 983090983088983089983088

[983091983093] I Saini J Rozra N Chandak S Aggarwal P K Sharmaand A Sharma ldquoailoring o electrical optical and structuralproperties o PVA by addition o Ag nanoparticlesrdquo MaterChem Phys vol 983089983091983097 pp 983096983088983090ndash983096983089983088 983090983088983089983091

[983091983094] S Mahendia A K omar and S Kumar ldquoNano-Ag dopinginduced changes in optical and electrical behaviour o PVA1047297lmsrdquo Materials Science and Engineering B vol 983089983095983094 no 983095 pp983093983091983088ndash983093983091983092 983090983088983089983089

[983091983095] M Abdelaziz and E M Abdelrazek ldquoEffect o dopant mixtureon structural optical and electron spin resonance properties o polyvinyl alcoholrdquo Physica B vol 983091983097983088 no 983089-983090 pp 983089ndash983097 983090983088983088983095

[983091983096] B Suo X Su J Wu D Chen A Wang and Z Guo ldquoPoly (vinyl alcohol) thin 1047297lm 1047297lled with CdSe-ZnS quantum dotsabrication characterization and optical propertiesrdquo MaterialsChemistry and Physics vol 983089983089983097 no 983089-983090 pp 983090983091983095ndash983090983092983090 983090983088983089983088

[983091983097] B Karthikeyan ldquoSpectroscopic studies on Ag-polyvinyl alcoholnanocomposite 1047297lmsrdquo Physica B vol 983091983094983092 no 983089ndash983092 pp 983091983090983096ndash983091983091983090983090983088983088983093

[983092983088] A S Kutsenko and V M Granchak ldquoPhotochemical synthesiso silver nanoparticles in polyvinyl alcohol matricesrdquo Teoreti-cal and Experimental Chemistry vol 983092983093no 983093 pp 983091983089983091ndash983091983089983096983090983088983088983097

[983092983089] C U Devi A K Sharma and V V R N Rao ldquoElectrical andoptical properties o pure and silver nitrate-doped polyvinylalcohol 1047297lmsrdquo Materials Letters vol 983093983094 no 983091 pp 983089983094983095ndash983089983095983092 983090983088983088983090

[983092983090] B G Streetman Solid State Electronic Devices Prentice HallNew Jersey NJ USA 983091rd edition 983089983097983097983088

[983092983091] J auc and R Grigorovici ldquoOptical properties and electronicstructure o amorphous germaniumrdquo Physica Status Solidi (B) vol 983089983093 no 983090 pp 983094983090983095ndash983094983091983095 983089983097983094983094

[983092983092] J Rozra I Saini A Sharma et al ldquoCu nanoparticles inducedstructural optical and electrical modi1047297cation in PVArdquo Materi-als Chemistry and Physics vol 983089983091983092 no 983090-983091 pp 983089983089983090983089ndash983089983089983090983094 983090983088983089983090

[983092983093] M Abdelaziz ldquoCerium (III) doping effects on optical andthermal properties o PVA 1047297lmsrdquo Physica B vol 983092983088983094 no 983094-983095pp 983089983091983088983088ndash983089983091983088983095 983090983088983089983089

[983092983094] C Kittle Introduction to Solid State Physics vol 983092983088983093 John Wiley amp Sons New York NY USA 983089983097983095983089

[983092983095] J D Jackson Classical Electrodynamics John Wiley amp Sons 983091rdedition 983089983097983097983097

[983092983096] M S Dresselhaus Solid State Physics Part II Optical Propertiesof Solids vol 983094 983090983088983088983089

[983092983097] J N Hodgson Optical Absorption and Dispersion in Solids Chapman amp Hall London UK 983089983097983095983089

[983093983088] Y Caglar S Ilican and M Caglar ldquoSingle-oscillator modeland determination o optical constants o spray pyrolyzedamorphous SnO2 thin 1047297lmsrdquo European Physical Journal B vol983093983096 no 983091 pp 983090983093983089ndash983090983093983094 983090983088983088983095

[983093983089] Y Seok Kim Electrical Conductivity of Segregated NetworkPolymer Nanoposites vol 983089983091983095 983090983088983088983095

[983093983090] Y Feldman A Puzenko and Y Ryabov ldquoDielectric relaxationphenomena in complex materialsrdquo in Advances in Chemical

Physics vol 983089983091983091 pp 983089ndash983089983090983093 Department o Applied Physics TeHebrew University o Jerusalem Jerusalem Israel 983090983088983088983094

[983093983091] S Mahendia A K omar R P Chahal P Goyal and S KumarldquoOptical and structural properties o poly(vinyl alcohol) 1047297lmsembedded with citrate-stabilized gold nanoparticlesrdquo Journal of Physics D vol 983092983092 no 983090983088 Article ID 983090983088983093983089983088983093 983090983088983089983089

[983093983092] S H Wemple and M DiDomenico ldquoBehavior o the electronicdielectric constant in covalent and ionic materialsrdquo Physical Review B vol 983091 no 983092 pp 983089983091983091983096ndash983089983091983093983089 983089983097983095983089

7272019 pva films

httpslidepdfcomreaderfullpva-films 1111

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2013Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The ScientifcWorld Journal

Impact Factor 1730

28 Days Fast Track Peer Review

All Subject Areas of Science

Submit at httpwwwtswjcom

7272019 pva films

httpslidepdfcomreaderfullpva-films 911

Journal o Nanomaterials 983097

10 105 11 115 12 125 1302

04

06

08

1

12

14

16

PVA

S1

S2

S3

(

n 2

minus

1 ) minus 1

E2 (eV2)

F983145983143983157983154983141 983089983093Plot o (2minus1) versus squared photon energy o pure PVAand doping samples

983137983138983148983141 983089 Dispersion parameters o 1047297lmsSamples 0

PVA 983089983093983094 983090983092983092 983093983089983097 983095983092983097

S983089 983089983092983096 983090983089983097 983093983088983092 983094983088983091

S983090 983089983091983095 983089983096983097 983092983097983095 983092983092983094

S983091 983089983089983097 983089983092983090 983092983096983095 983090983088983093

4 Conclusions

Preparation o silver nanoparticles by laser ablation methodat different 1047298uencies o laser pulse in pure water is investi-gated Te EM analysis revealed that generated nanoparti-

cles in this experimental condition are almost spherical andtheir average size was 983094ndash983089983090 nm and with increasing the laserpulse 1047298uence the size o nanoparticles is decreased Te X-ray diffraction spectrum reveals that the number o crystal-lographic planes at certain angles is increased afer doping Agnanoparticles in the structure o PVA FIR spectrum peakscorrespond to molecular vibrations and chemical bondsindicate the presence o silver in the PVA polymer structureTe optical bandgap energy o the samples is decreasedwith increasing the concentrations o silver nanoparticlesReractive index and dielectric constant are decreased withincreasing the concentration o Ag nanoparticles Increaseo dopant concentration resulted in a decrease in real part

o the optical conductivity because o segregation effectTe reractive index and consequently the related dispersionparameters o PVA and doped PVA have been determinedand explained using the Wemple-DiDomenico model

References

[983089] A Nimrodh Ananth and S Umapathy ldquoOn the optical andthermal properties o in situex situ reduced Ag NPrsquosPVAcomposites and its role as a simple SPR-based protein sensorrdquo Applied Nanoscience vol 983089 no 983090 pp 983096983095ndash983097983094 983090983088983089983089

[983090] G Nesher G Marom and D Avnir ldquoMetal-polymer compos-ites synthesis and characterization o polyaniline and other

polymer at Silver compositionsrdquo Chemistry of Materialsvol983090983088no 983089983091 pp 983092983092983090983093ndash983092983092983091983090 983090983088983088983096

[983091] P-H Wang Y-Z Wu andQ-R ZhuldquoPolymermetal compositeparticles polymer core and metal shellrdquo Journal of MaterialsScience Letters vol 983090983089 no 983090983091 pp 983089983096983090983093ndash983089983096983090983096 983090983088983088983090

[983092] S Clemenson P Alcouffe L David and E Espuche ldquoStructureand morphology o membranes prepared rom polyvinyl alco-hol and silver nitrate in1047298uence o the annealing treatment ando the 1047297lm thicknessrdquo Desalination vol 983090983088983088 no 983089-983091 pp 983092983091983095ndash983092983091983097 983090983088983088983094

[983093] K Akamatsu S akei M Mizuhata et al ldquoPreparation andcharacterization o polymer thin 1047297lms containing silver andsilver sul1047297de nanoparticlesrdquo Tin Solid Films vol 983091983093983097 no 983089 pp983093983093ndash983094983088 983090983088983088983088

[983094] R Zeng M Z Rong M Q Zhang H C Liang and H MZeng ldquoLaser ablation o polymer-based silver nanocompositesrdquo Applied Surface Science vol 983089983096983095 no 983091-983092 pp 983090983091983097ndash983090983092983095 983090983088983088983090

[983095] S Mahendia A K omar and S Kumar ldquoElectrical conduc-tivity and dielectric spectroscopic studies o PVA-Ag nanocom-posite 1047297lmsrdquo Journal of Alloys and Compounds vol 983093983088983096 no 983090pp 983092983088983094ndash983092983089983089 983090983088983089983088

[983096] N Singh and P K Khanna ldquoIn situ synthesis o silver nano-particles in polymethylmethacrylaterdquo Materials Chemistry and Physics vol 983089983088983092 no 983090-983091 pp 983091983094983095ndash983091983095983090 983090983088983088983095

[983097] P K Khanna R Gokhale V V V S Subbarao A K Vish-wanath B K Das and C V V Satyanarayana ldquoPVA stabilizedgold nanoparticles by use o unexplored albeit conventionalreducing agentrdquo Materials Chemistry and Physics vol 983097983090 no983089 pp 983090983090983097ndash983090983091983091 983090983088983088983093

[983089983088] K Akamatsu S akei M Mizuhata et al ldquoPreparation andcharacterization o polymer thin 1047297lms containing silver andsilver sul1047297de nanoparticlesrdquo Tin Solid Films vol 983091983093983097 no 983089 pp983093983093ndash983094983088 983090983088983088983088

[983089983089] I Hussain M Brust A J Papworth and A I Cooper

ldquoPreparationo acrylate-stabilized goldand silver hydrosols andgold-polymer composite 1047297lmsrdquo Langmuir vol 983089983097 no 983089983089 pp983092983096983091983089ndash983092983096983091983093 983090983088983088983091

[983089983090] S A Zavyalov A N Pivkina and J Schoonman ldquoFormationand characterization o metal-polymer nanostructured com-positesrdquo Solid State Ionics vol 983089983092983095 no 983091-983092 pp 983092983089983093ndash983092983089983097 983090983088983088983090

[983089983091] J Lee D Bhattacharyya A J Easteal and J B Metson ldquoProp-erties o nano-ZnOpoly(vinyl alcohol)poly(ethylene oxide)composite thin 1047297lmsrdquo Current Applied Physics vol 983096 no 983089 pp983092983090ndash983092983095 983090983088983088983096

[983089983092] Z Zhong D Wang Y Cui M W Bockrath and C H LieberldquoNanowire crossbar arrays as address decoders or integratednanosystemsrdquo Science vol 983091983088983090 no 983093983094983092983097 pp 983089983091983095983095ndash983089983091983095983097 983090983088983088983091

[983089983093] D S Hopkins D Pekker P M Goldbart and A Bezryadin

ldquoQuantum intererence device made by DNA templating o superconducting nanowiresrdquo Science vol 983091983088983096 no 983093983095983090983097 pp983089983095983094983090ndash983089983095983094983093 983090983088983088983093

[983089983094] S Clemenson D Leonard D Sage L David and E EspucheldquoMetal nanocomposite 1047297lms prepared in Situ rom PVA andsilver nitrate Study o the nanostructuration process andmorphology as a unction o the in Situ routesrdquo Journal of Polymer Science A vol 983092983094 no 983094 pp 983090983088983094983090ndash983090983088983095983089 983090983088983088983096

[983089983095] M K emgire and S S Joshi ldquoOptical and structural studies o silver nanoparticlesrdquo Radiation Physics and Chemistry vol 983095983089no 983093 pp 983089983088983091983097ndash983089983088983092983092 983090983088983088983092

[983089983096] M Zheng M Gu Y Jin and G Jin ldquoOptical properties o silver-dispersed PVP thin 1047297lmrdquo Materials Research Bulletin vol 983091983094no 983093-983094 pp 983096983093983091ndash983096983093983097 983090983088983088983089

7272019 pva films

httpslidepdfcomreaderfullpva-films 1011

983089983088 Journal o Nanomaterials

[983089983097] O L A Monti J Fourkas and D J Nesbitt ldquoDiffraction-limited photogeneration and characterization o silver nanopar-ticlesrdquo Journal of Physical Chemistry B vol 983089983088983096 no 983093 pp 983089983094983088983092ndash983089983094983089983090 983090983088983088983092

[983090983088] K L Kelly E Coronado L L Zhao and G C Schatz ldquoTeopti-cal properties o metal nanoparticles the in1047298uence o sizeshape and dielectric environmentrdquo Journal of Physical Che-

mistry B vol 983089983088983095 no 983091 pp 983094983094983096ndash983094983095983095 983090983088983088983091

[983090983089] H Weickmann J C iller R Tomann and R MulhauptldquoMetallized organoclays as new intermediates or aqueous nan-ohybrid dispersions nanohybrid catalysts and antimicrobialpolymer hybrid nanocompositesrdquo Macromolecular Materialsand Engineering vol 983090983097983088 no 983097 pp 983096983095983093ndash983096983096983091 983090983088983088983093

[983090983090] U Keirbeg and M Vollmer Optical Properties of Metal Clusters vol 983090983093 o Springer Series in Material Science 983089983097983097983093

[983090983091] S Chen and J M Sommers ldquoAlkanethiolate-protected coppernanoparticles spectroscopy electrochemistry and solid-statemorphological evolutionrdquo Journal of Physical Chemistry B vol983089983088983093 no 983091983095 pp 983096983096983089983094ndash983096983096983090983088 983090983088983088983089

[983090983092] A A Scalisi G Compagnini L DrsquoUrso and O Puglisi ldquoNon-linearopticalactivity in Ag-SiO

2 nanocomposite thin 1047297lms with

different silver concentrationrdquo Applied Surface Science vol 983090983090983094no 983089ndash983091 pp 983090983091983095ndash983090983092983089 983090983088983088983092

[983090983093] G Yang W Wang Y Zhou H Lu G Yang and Z Chen ldquoLin-ear and nonlinear optical properties o Ag nanoclusterBaiO3

composite 1047297lmsrdquo Applied Physics Letters vol 983096983089 no 983090983089 pp983091983097983094983097ndash983091983097983095983089 983090983088983088983090

[983090983094] H B Liao R F Xiao H Wang K S Wong and G K L WongldquoLarge third-order optical nonlinearity in AuiO2 composite1047297lms measured on a emtosecond time scalerdquo Applied PhysicsLetters vol 983095983090 no 983089983093 pp 983089983096983089983095ndash983089983096983089983097 983089983097983097983096

[983090983095] A K Sarychev D J Bergman and Y Yagil ldquoTeory o theoptical and microwave properties o metal-dielectric 1047297lmsrdquoPhysical Review B vol 983093983089 no 983096 pp 983093983091983094983094ndash983093983091983096983093 983089983097983097983093

[983090983096] G Mie ldquoBeitrage zur Optik truber Medien speziell kolloidalerMetallosungenrdquo Annalen der Physik vol 983091983091983088 pp 983091983095983095ndash983092983092983093 983089983097983088983096

[983090983097] R Gans ldquoUber die Form ultramikroskopischer Silberteilchenrdquo Annalen der Physik vol 983091983093983090 no 983089983088 pp 983090983095983088ndash983090983096983092 983089983097983089983093

[983091983088] S Link and M A El-Sayed ldquoSpectral properties and relaxationdynamics o surace plasmon electronic oscillations in gold andsilver nanodots and nanorodsrdquo Journal of Physical Chemistry B vol 983089983088983091 no 983092983088 pp 983096983092983089983088ndash983096983092983090983094 983089983097983097983097

[983091983089] G Fussell J Tomas J Scanlon A Lowman and M Mar-colongo ldquoTe effect o protein-ree versus protein-containingmedium on the mechanical properties and uptake o ions o PVAPVP hydrogelsrdquo Journalof BiomaterialsScience vol983089983094 no983092 pp 983092983096983097ndash983093983088983091 983090983088983088983093

[983091983090] suji Mizuki S Ozono and M suji ldquoLaser-induced sil-

ver nanocrystal ormation in polyvinylpyrrolidone solutionsrdquo Journal of Photochemistry and Photobiology A vol 983090983088983094 no 983090-983091pp 983089983091983092ndash983089983091983097 983090983088983088983097

[983091983091] J-P Sylvestre S Poulin A V Kabashin E Sacher M Meunierand J H Luong ldquoSurace chemistry o gold nanoparticlesproduced by laser ablation in aqueous mediardquo Journal of Physical Chemistry B vol 983089983088983096 no 983092983091 pp 983089983094983096983094983092ndash983089983094983096983094983097 983090983088983088983092

[983091983092] A Gautam and S Ram ldquoPreparation and thermomechanicalproperties o Ag-PVA nanocomposite 1047297lmsrdquo Materials Chem-istry and Physics vol 983089983089983097 no 983089-983090 pp 983090983094983094ndash983090983095983089 983090983088983089983088

[983091983093] I Saini J Rozra N Chandak S Aggarwal P K Sharmaand A Sharma ldquoailoring o electrical optical and structuralproperties o PVA by addition o Ag nanoparticlesrdquo MaterChem Phys vol 983089983091983097 pp 983096983088983090ndash983096983089983088 983090983088983089983091

[983091983094] S Mahendia A K omar and S Kumar ldquoNano-Ag dopinginduced changes in optical and electrical behaviour o PVA1047297lmsrdquo Materials Science and Engineering B vol 983089983095983094 no 983095 pp983093983091983088ndash983093983091983092 983090983088983089983089

[983091983095] M Abdelaziz and E M Abdelrazek ldquoEffect o dopant mixtureon structural optical and electron spin resonance properties o polyvinyl alcoholrdquo Physica B vol 983091983097983088 no 983089-983090 pp 983089ndash983097 983090983088983088983095

[983091983096] B Suo X Su J Wu D Chen A Wang and Z Guo ldquoPoly (vinyl alcohol) thin 1047297lm 1047297lled with CdSe-ZnS quantum dotsabrication characterization and optical propertiesrdquo MaterialsChemistry and Physics vol 983089983089983097 no 983089-983090 pp 983090983091983095ndash983090983092983090 983090983088983089983088

[983091983097] B Karthikeyan ldquoSpectroscopic studies on Ag-polyvinyl alcoholnanocomposite 1047297lmsrdquo Physica B vol 983091983094983092 no 983089ndash983092 pp 983091983090983096ndash983091983091983090983090983088983088983093

[983092983088] A S Kutsenko and V M Granchak ldquoPhotochemical synthesiso silver nanoparticles in polyvinyl alcohol matricesrdquo Teoreti-cal and Experimental Chemistry vol 983092983093no 983093 pp 983091983089983091ndash983091983089983096983090983088983088983097

[983092983089] C U Devi A K Sharma and V V R N Rao ldquoElectrical andoptical properties o pure and silver nitrate-doped polyvinylalcohol 1047297lmsrdquo Materials Letters vol 983093983094 no 983091 pp 983089983094983095ndash983089983095983092 983090983088983088983090

[983092983090] B G Streetman Solid State Electronic Devices Prentice HallNew Jersey NJ USA 983091rd edition 983089983097983097983088

[983092983091] J auc and R Grigorovici ldquoOptical properties and electronicstructure o amorphous germaniumrdquo Physica Status Solidi (B) vol 983089983093 no 983090 pp 983094983090983095ndash983094983091983095 983089983097983094983094

[983092983092] J Rozra I Saini A Sharma et al ldquoCu nanoparticles inducedstructural optical and electrical modi1047297cation in PVArdquo Materi-als Chemistry and Physics vol 983089983091983092 no 983090-983091 pp 983089983089983090983089ndash983089983089983090983094 983090983088983089983090

[983092983093] M Abdelaziz ldquoCerium (III) doping effects on optical andthermal properties o PVA 1047297lmsrdquo Physica B vol 983092983088983094 no 983094-983095pp 983089983091983088983088ndash983089983091983088983095 983090983088983089983089

[983092983094] C Kittle Introduction to Solid State Physics vol 983092983088983093 John Wiley amp Sons New York NY USA 983089983097983095983089

[983092983095] J D Jackson Classical Electrodynamics John Wiley amp Sons 983091rdedition 983089983097983097983097

[983092983096] M S Dresselhaus Solid State Physics Part II Optical Propertiesof Solids vol 983094 983090983088983088983089

[983092983097] J N Hodgson Optical Absorption and Dispersion in Solids Chapman amp Hall London UK 983089983097983095983089

[983093983088] Y Caglar S Ilican and M Caglar ldquoSingle-oscillator modeland determination o optical constants o spray pyrolyzedamorphous SnO2 thin 1047297lmsrdquo European Physical Journal B vol983093983096 no 983091 pp 983090983093983089ndash983090983093983094 983090983088983088983095

[983093983089] Y Seok Kim Electrical Conductivity of Segregated NetworkPolymer Nanoposites vol 983089983091983095 983090983088983088983095

[983093983090] Y Feldman A Puzenko and Y Ryabov ldquoDielectric relaxationphenomena in complex materialsrdquo in Advances in Chemical

Physics vol 983089983091983091 pp 983089ndash983089983090983093 Department o Applied Physics TeHebrew University o Jerusalem Jerusalem Israel 983090983088983088983094

[983093983091] S Mahendia A K omar R P Chahal P Goyal and S KumarldquoOptical and structural properties o poly(vinyl alcohol) 1047297lmsembedded with citrate-stabilized gold nanoparticlesrdquo Journal of Physics D vol 983092983092 no 983090983088 Article ID 983090983088983093983089983088983093 983090983088983089983089

[983093983092] S H Wemple and M DiDomenico ldquoBehavior o the electronicdielectric constant in covalent and ionic materialsrdquo Physical Review B vol 983091 no 983092 pp 983089983091983091983096ndash983089983091983093983089 983089983097983095983089

7272019 pva films

httpslidepdfcomreaderfullpva-films 1111

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2013Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The ScientifcWorld Journal

Impact Factor 1730

28 Days Fast Track Peer Review

All Subject Areas of Science

Submit at httpwwwtswjcom

7272019 pva films

httpslidepdfcomreaderfullpva-films 1011

983089983088 Journal o Nanomaterials

[983089983097] O L A Monti J Fourkas and D J Nesbitt ldquoDiffraction-limited photogeneration and characterization o silver nanopar-ticlesrdquo Journal of Physical Chemistry B vol 983089983088983096 no 983093 pp 983089983094983088983092ndash983089983094983089983090 983090983088983088983092

[983090983088] K L Kelly E Coronado L L Zhao and G C Schatz ldquoTeopti-cal properties o metal nanoparticles the in1047298uence o sizeshape and dielectric environmentrdquo Journal of Physical Che-

mistry B vol 983089983088983095 no 983091 pp 983094983094983096ndash983094983095983095 983090983088983088983091

[983090983089] H Weickmann J C iller R Tomann and R MulhauptldquoMetallized organoclays as new intermediates or aqueous nan-ohybrid dispersions nanohybrid catalysts and antimicrobialpolymer hybrid nanocompositesrdquo Macromolecular Materialsand Engineering vol 983090983097983088 no 983097 pp 983096983095983093ndash983096983096983091 983090983088983088983093

[983090983090] U Keirbeg and M Vollmer Optical Properties of Metal Clusters vol 983090983093 o Springer Series in Material Science 983089983097983097983093

[983090983091] S Chen and J M Sommers ldquoAlkanethiolate-protected coppernanoparticles spectroscopy electrochemistry and solid-statemorphological evolutionrdquo Journal of Physical Chemistry B vol983089983088983093 no 983091983095 pp 983096983096983089983094ndash983096983096983090983088 983090983088983088983089

[983090983092] A A Scalisi G Compagnini L DrsquoUrso and O Puglisi ldquoNon-linearopticalactivity in Ag-SiO

2 nanocomposite thin 1047297lms with

different silver concentrationrdquo Applied Surface Science vol 983090983090983094no 983089ndash983091 pp 983090983091983095ndash983090983092983089 983090983088983088983092

[983090983093] G Yang W Wang Y Zhou H Lu G Yang and Z Chen ldquoLin-ear and nonlinear optical properties o Ag nanoclusterBaiO3

composite 1047297lmsrdquo Applied Physics Letters vol 983096983089 no 983090983089 pp983091983097983094983097ndash983091983097983095983089 983090983088983088983090

[983090983094] H B Liao R F Xiao H Wang K S Wong and G K L WongldquoLarge third-order optical nonlinearity in AuiO2 composite1047297lms measured on a emtosecond time scalerdquo Applied PhysicsLetters vol 983095983090 no 983089983093 pp 983089983096983089983095ndash983089983096983089983097 983089983097983097983096

[983090983095] A K Sarychev D J Bergman and Y Yagil ldquoTeory o theoptical and microwave properties o metal-dielectric 1047297lmsrdquoPhysical Review B vol 983093983089 no 983096 pp 983093983091983094983094ndash983093983091983096983093 983089983097983097983093

[983090983096] G Mie ldquoBeitrage zur Optik truber Medien speziell kolloidalerMetallosungenrdquo Annalen der Physik vol 983091983091983088 pp 983091983095983095ndash983092983092983093 983089983097983088983096

[983090983097] R Gans ldquoUber die Form ultramikroskopischer Silberteilchenrdquo Annalen der Physik vol 983091983093983090 no 983089983088 pp 983090983095983088ndash983090983096983092 983089983097983089983093

[983091983088] S Link and M A El-Sayed ldquoSpectral properties and relaxationdynamics o surace plasmon electronic oscillations in gold andsilver nanodots and nanorodsrdquo Journal of Physical Chemistry B vol 983089983088983091 no 983092983088 pp 983096983092983089983088ndash983096983092983090983094 983089983097983097983097

[983091983089] G Fussell J Tomas J Scanlon A Lowman and M Mar-colongo ldquoTe effect o protein-ree versus protein-containingmedium on the mechanical properties and uptake o ions o PVAPVP hydrogelsrdquo Journalof BiomaterialsScience vol983089983094 no983092 pp 983092983096983097ndash983093983088983091 983090983088983088983093

[983091983090] suji Mizuki S Ozono and M suji ldquoLaser-induced sil-

ver nanocrystal ormation in polyvinylpyrrolidone solutionsrdquo Journal of Photochemistry and Photobiology A vol 983090983088983094 no 983090-983091pp 983089983091983092ndash983089983091983097 983090983088983088983097

[983091983091] J-P Sylvestre S Poulin A V Kabashin E Sacher M Meunierand J H Luong ldquoSurace chemistry o gold nanoparticlesproduced by laser ablation in aqueous mediardquo Journal of Physical Chemistry B vol 983089983088983096 no 983092983091 pp 983089983094983096983094983092ndash983089983094983096983094983097 983090983088983088983092

[983091983092] A Gautam and S Ram ldquoPreparation and thermomechanicalproperties o Ag-PVA nanocomposite 1047297lmsrdquo Materials Chem-istry and Physics vol 983089983089983097 no 983089-983090 pp 983090983094983094ndash983090983095983089 983090983088983089983088

[983091983093] I Saini J Rozra N Chandak S Aggarwal P K Sharmaand A Sharma ldquoailoring o electrical optical and structuralproperties o PVA by addition o Ag nanoparticlesrdquo MaterChem Phys vol 983089983091983097 pp 983096983088983090ndash983096983089983088 983090983088983089983091

[983091983094] S Mahendia A K omar and S Kumar ldquoNano-Ag dopinginduced changes in optical and electrical behaviour o PVA1047297lmsrdquo Materials Science and Engineering B vol 983089983095983094 no 983095 pp983093983091983088ndash983093983091983092 983090983088983089983089

[983091983095] M Abdelaziz and E M Abdelrazek ldquoEffect o dopant mixtureon structural optical and electron spin resonance properties o polyvinyl alcoholrdquo Physica B vol 983091983097983088 no 983089-983090 pp 983089ndash983097 983090983088983088983095

[983091983096] B Suo X Su J Wu D Chen A Wang and Z Guo ldquoPoly (vinyl alcohol) thin 1047297lm 1047297lled with CdSe-ZnS quantum dotsabrication characterization and optical propertiesrdquo MaterialsChemistry and Physics vol 983089983089983097 no 983089-983090 pp 983090983091983095ndash983090983092983090 983090983088983089983088

[983091983097] B Karthikeyan ldquoSpectroscopic studies on Ag-polyvinyl alcoholnanocomposite 1047297lmsrdquo Physica B vol 983091983094983092 no 983089ndash983092 pp 983091983090983096ndash983091983091983090983090983088983088983093

[983092983088] A S Kutsenko and V M Granchak ldquoPhotochemical synthesiso silver nanoparticles in polyvinyl alcohol matricesrdquo Teoreti-cal and Experimental Chemistry vol 983092983093no 983093 pp 983091983089983091ndash983091983089983096983090983088983088983097

[983092983089] C U Devi A K Sharma and V V R N Rao ldquoElectrical andoptical properties o pure and silver nitrate-doped polyvinylalcohol 1047297lmsrdquo Materials Letters vol 983093983094 no 983091 pp 983089983094983095ndash983089983095983092 983090983088983088983090

[983092983090] B G Streetman Solid State Electronic Devices Prentice HallNew Jersey NJ USA 983091rd edition 983089983097983097983088

[983092983091] J auc and R Grigorovici ldquoOptical properties and electronicstructure o amorphous germaniumrdquo Physica Status Solidi (B) vol 983089983093 no 983090 pp 983094983090983095ndash983094983091983095 983089983097983094983094

[983092983092] J Rozra I Saini A Sharma et al ldquoCu nanoparticles inducedstructural optical and electrical modi1047297cation in PVArdquo Materi-als Chemistry and Physics vol 983089983091983092 no 983090-983091 pp 983089983089983090983089ndash983089983089983090983094 983090983088983089983090

[983092983093] M Abdelaziz ldquoCerium (III) doping effects on optical andthermal properties o PVA 1047297lmsrdquo Physica B vol 983092983088983094 no 983094-983095pp 983089983091983088983088ndash983089983091983088983095 983090983088983089983089

[983092983094] C Kittle Introduction to Solid State Physics vol 983092983088983093 John Wiley amp Sons New York NY USA 983089983097983095983089

[983092983095] J D Jackson Classical Electrodynamics John Wiley amp Sons 983091rdedition 983089983097983097983097

[983092983096] M S Dresselhaus Solid State Physics Part II Optical Propertiesof Solids vol 983094 983090983088983088983089

[983092983097] J N Hodgson Optical Absorption and Dispersion in Solids Chapman amp Hall London UK 983089983097983095983089

[983093983088] Y Caglar S Ilican and M Caglar ldquoSingle-oscillator modeland determination o optical constants o spray pyrolyzedamorphous SnO2 thin 1047297lmsrdquo European Physical Journal B vol983093983096 no 983091 pp 983090983093983089ndash983090983093983094 983090983088983088983095

[983093983089] Y Seok Kim Electrical Conductivity of Segregated NetworkPolymer Nanoposites vol 983089983091983095 983090983088983088983095

[983093983090] Y Feldman A Puzenko and Y Ryabov ldquoDielectric relaxationphenomena in complex materialsrdquo in Advances in Chemical

Physics vol 983089983091983091 pp 983089ndash983089983090983093 Department o Applied Physics TeHebrew University o Jerusalem Jerusalem Israel 983090983088983088983094

[983093983091] S Mahendia A K omar R P Chahal P Goyal and S KumarldquoOptical and structural properties o poly(vinyl alcohol) 1047297lmsembedded with citrate-stabilized gold nanoparticlesrdquo Journal of Physics D vol 983092983092 no 983090983088 Article ID 983090983088983093983089983088983093 983090983088983089983089

[983093983092] S H Wemple and M DiDomenico ldquoBehavior o the electronicdielectric constant in covalent and ionic materialsrdquo Physical Review B vol 983091 no 983092 pp 983089983091983091983096ndash983089983091983093983089 983089983097983095983089

7272019 pva films

httpslidepdfcomreaderfullpva-films 1111

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2013Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The ScientifcWorld Journal

Impact Factor 1730

28 Days Fast Track Peer Review

All Subject Areas of Science

Submit at httpwwwtswjcom

7272019 pva films

httpslidepdfcomreaderfullpva-films 1111

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2013Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The ScientifcWorld Journal

Impact Factor 1730

28 Days Fast Track Peer Review

All Subject Areas of Science

Submit at httpwwwtswjcom