Aromatic Diimides – Potential Dyes for Use in Smart Films ...

Aromatic Diimides – Potential Dyes for Use in Smart Films and Fibers

New aromatic diimide fluorescent dyes have been prepared with potential for use as chemical sensors and in chromogenic polymers. These dyes have been designed to utilize excited state electron transfer reactions as the means for sensing chemical species. For example, an aniline end-capped anthryl diimides functions effectively as an “on-off’ sensor for pH and the detection of phosphoryl halide based chemical warfare agents, such as Sarin. In the absence of analytes, fluorescence from this dye is completely quenched by excited state electron transfer from the terminal amines. Reaction of these amines inhibits electron transfer and activates the fluorescence of the dye. Another substituted anthryl diimide is presented with the capability to detect pH and nitroaromatic compounds, such as TNT. Films prepared by doping small amounts (less than 0.1 weight percent) of several of these dyes in polymers such as linear low density polyethylene exhibit thermochromism. At room temperature, these films fluoresce reddish-orange. Upon heating, the fluorescence turns green. This process is reversible – cooling the films to room temperature restores the orange emission.

1

National Aeronautics and Space Administration

www.nasa.gov

Aromatic Diimides –

Potential Dyes for Use in Smart Films and Fibers

Advances in Colorants, Chemicals, Finishes and Fibrous Materials

Symposium Greenville, SC June 3-4, 2008

Michael A. Meador, Daniel S. Tyson, Faysal

Ilhan, Ashley Carbaugh

Polymers BranchStructures and Materials Division

NASA Glenn Research CenterCleveland, OH 44135

[email protected](216) 433-9518

mailto:[email protected]

2


www.nasa.gov

Polymers Branch Overview

Propulsion Materials•

High use temperature polymers and composites

•

Material concepts for fan containment

•

New polymers and composites for COPVs

Thermal Control Materials•

High conductivity polymers and composites for radiators and heat exchangers

• Durable, lightweight insulation•

Low permeability, microcrack

resistant polymers and composites

Nanostructured

Materials• Nanocomposites (clay, graphene)• Nanotube based composites• Durable, polymer cross-linked aerogels

Functional Polymers• Adaptive polymers• Fluorescent sensors• Conductive membranes

Enable:• Reduced Mass• Enhanced Performance• Improved Durability• Reduced Cost

Design

ProcessingSynthesis

Characterization

3


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450 500 550 600 650 700 750 8000.0

0.2

0.4

0.6

0.8

1.0

Emis

sion

Inte

nsity

(mV)

Wavelength (nm)

SOCl2

Φ

= 0.12Cl2

Φ

= 0.19Cl2

S Φ

= 0.20

Cl Φ

= 0.11Me Φ

= 0.00

Organic Materials for Molecular SensorsTechnology Background

Fluorescence based methods are highly sensitive for the detection of chemical and biological species and can be used for the determination of strain and/or degradation in materials.

Fluorescent dye enhanced photomicrocraph

of Alfalfa Root

Fluorescence based strain sensors –

courtesy CWRU

NASA Applications

•

Astronaut Health Management

•

Air & Water Quality Monitoring

•

Integrated Vehicle Health Management

Research and Results

Developed route to novel diimide

materials with potential use in molecular sensors, electronics and electroluminescent devices

Tyson, Ilhan

and Meador Journal of the American Chemical Society 2006, 128, 702-703

NN

O

O

Ph

Ph O

O

H2N NH2

NO Fluorescence

NN

O

O

Ph

Ph O

O

+H3N NH3+

H+

Fluorescent

+ BaseDiamine + Acid

+ Acetyl ClP

O

O

O

POCl

O

O

POCl

O

Cl

PCl

S

Cl

POF

O

Sarin

Methylphosphonic dichloride (Cl2)

Dimethylphosphinic chloride (Cl)

Dimethyl methylphosphonate (Me)

Ethyl dichlorothiophosphate (Cl2S)

“On-Off”

Fluorescent Sensor for pH and Chemical Warfare Agents

Ilhan, Tyson and Meador Chemisty of Materials 2004, 16, 2978-80

N

N

O

O

O

O

R

R

Perylene

Crystals

Perylene

Doped Polystyrene

Perylene

in Solution

Novel Perylene

Diimide

Has Potential as Strain Sensor

Red Luminesence

in Solid State Due to Exciplex


www.nasa.gov

Photoenolization

of o-Methylphenyl

KetonesCH3

Ph

O CH2

Ph

OH 3*

CH2

OH

Ph

CH2

Ph

OH

hν

iscisc

EHO Ph

E

EE

Z

E

o-MeBP

Porter, G.; Tchir, M. J. Chem. Soc. A 1971, 3772Yang, N.C; Rivas, C.J. J. Am. Chem. Soc. 1961, 83, 2213

•

Clean, high yield route to fused 6-membered rings

Regio- and stereospecific• Not applied to polymer synthesis


www.nasa.gov

Diels-Alder Trapping of Bis(o-xylylenol)s is Versatile

C H 3

C H 3

A r

O

A r

O

" "

h ν

EE

E

E

E

E

H O P h

P h O H

X

XP h O H

P h O Hn

O H

P h

H O

P h


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Chemical Yields for Bisadduct

Formation are High

Ar'

O

Ar

O

X

Y

Y

XHO Ar'

HO Ar

1 2 (X=CO2Me, Y=H)3 (X=Y=CO2Me)

hν

Ar Ar’ X Y 2 3Ph Ph MeAcry E H 25+56Ph Ph Me2Fum E E 86

4-Me 4-Me MeAcry E H 904-Me 4-Me Me2Fum E E 82

4-OMe 4-OMe MeAcry E H 754-OMe 4-OMe Me2Fum E E 86

4-OC12H25 4-OC12H25 MeAcry E H 804-OC12H25 4-OC12H25 Me2Fum E E 80

4-CN 4-CN MeAcry E H 97


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Reaction Progess

Can Be Monitored by 1H nmr

CH3

CH3

Ph

O

Ph

O

Ph OHCO2Me

MeO2CPh OH

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Mono-

and Bisadduct

Quantum Yield Effected by Extent of

Diketone

Conversion

% Conversion of 1

0 20 40 60 80 100

Φ

0.0

0.2

0.4

0.6

0.8

1.0

Bisadduct formationMonoaddduct formationLoss of Diketone

MeO2CCO2Me

O

Ph

Ph OHCO2Me

CO2Me

hν Ph OHCO2Me

CO2MePh OH

MeO2C

MeO2C

1

O

Ph

O

PhMeO2C

CO2Me

hν

E/Z photoenol

formation is 1:1 →

Maximum theoretical quantum yield for monoadduct

formation is 0.5

Φ

= moles of photoproductEinstein of light


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Bisadducts

are Readily Converted into Anthracenes

Ar OH

Ar OH

X

Y

Y

X

X

Y

Ar

Ar

X

Y

Ar

X

Y

Ar

X

Y

HCl/Ac2O

N2Reflux, 3h

2 3

4

DDQ/PhClN2

Reflux, 18h Ar X Y 3 4Ph E H 90 96Ph E E 100 80

4-MeOPh E H 87 814-MeOPh E E 80 80

4-FPh E H 89 724-FPh E E 68 70

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Versatile Route to Arenes

CH3

O

Ph

H3CO

Ph

Ph Ph

Ph Ph

NN

O

O

O

O

R R

Ph

Ph

N

N

O

O

R

O

O

R

Ph

Ph

N

N

O

O

R

O

OR

N

N

Ph

Ph

O

O

O

O

R

R

Ph

PhPh

PhN N

NN

O R R O

OO

O

OO

O

R R

N

N N

O

O

R

O

O

R

O

R O

NOR

O Ph

Ph

Ph

Ph

J. Am. Chem. Soc. 2006, 128, 702-703 Org. Lett. 2006, 8, 577-80.

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New Approaches to Perylene

Diimides

N

N

O

O

O

O

R

R

N

ONO

O O

R

RZ-Shaped

Linear

Ph

O

Ph

O

N

O

O

n-C8H17

6

hν N

N

O

n-C8H17

O

HO Ph

HO Ph

O

O

n-C8H175

+

hνPh

HO

Ph

OH

7

8

1. p-TsOH/Toluene, reflux, N2

2. DDQ/Chlorobenzene, reflux, N2

R= n-C8H1

N

N

O

n-C8H17

O

Ph

Ph

O

O

n-C8H17

•

Perylene

diimides are used in a wide array of materials, including electron transfer systems, liquid crystals, photovoltaics, and fluorescent sensors.

•

Conventional synthetic routes to perylene

dimides

focused on linear derivatives –

commercial availability of dianhydride.• New approach provides route to Z-shaped perylene

bisimides

12


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Absorption and Emission Spectra of Various Z-shaped Perylene

Diimides

350 400 450 500 5500.0

0.2

0.4

0.6

0.8

1.0

Nor

mal

ized

Abs

orpt

ion

Wavelength (nm)

Hexyloxy Octyl Methoxy

500 550 600 650 7000.0

0.2

0.4

0.6

0.8

1.0

Nor

mal

ized

PL

Wavelength (nm)

Hexyloxy Octyl Methoxy

N

N

X

X

O

R

O

O

R

O

Hexyloxy

R=p-C6

H13

O-Ph, X = HOctyl

R = n-C8

H17

, X=HMethoxy

R = n-C8

H17

, X=OCH3

Φf

(CH2

Cl2

)Octyl

= 0.67p- Hexyloxyphenyl

= 0.031

13


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Perylene

Diimide

Exhibits Excimer

Fluorescence in the Solid State

Perylene

Crystals

Perylene

Doped

Polystyrene

Perylene

in Solution

•

Difference in emission color due to the formation of excited state complexes (exciplexes) in which perylenes

form stacks•

Potential to use this phenomenon in the design of thermo-

and mechanochromic

polymers

14


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Preparation of N-Octyl

Benzo[e]pyrene

Diimide

Ph O

OPhhν

N

O

R

O

N

N

O

O

R

R

O

O

HOPh

HOPh

N

N

O

O

R

R

O

O

Ph

Ph

N

N

O

O

R

R

O

O

Ph

Ph

11

12

132

R = n-C8H17 p-TsOH/TolueneReflux

16h

S8/Ph2O

Reflux, 4h

81%

96%52%

15


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Absorption and Emission of Phenanthrene

and Benzo[e]pyrene

Bisimides

and Benzo[e]pyrene

300 400 500 6000

5000

10000

15000

20000

25000

Wavelength (nm)

Extin

ctio

n C

oeffi

cien

t (M

-1cm

-1)

0.0

0.2

0.4

0.6

0.8

1.0

Norm

alized PL

N

N

O

O

n-C8H17

n-C8H17

O

O

N

N

O

O

n-C8H17

n-C8H17

O

O

1

2

3

23

1

Φ = 0.24

Φ = 0.037

Φ = 0.054

Spectra and quantum yields measured in CH2

Cl2

16


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Synthesis of Anthracene Diimides

CH3

OO

H3C

X

X

N

O

O

R

NN

O

OO

O

R R

NN

O

OO

O

R RNN

O

OO

O

R R

HO

OH

X

X

X

X

X

X

hν

p-TsOH/ TolueneReflux, N2

Sulfur/ Ph2O

Reflux, N2

88-97%

77-98%26-71%

X = H, OCH3, CNR = n-C8H17, Ph, 4-MeOPh, 4- (C6H13O)Ph, 4-NO2Ph

17


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Synthesis of Tetraaryl

Diimides –

Trapping Unaffected by Steric

Hindrance

O

O

X

Y

X

Y

hν (Pyrex)

N

O

O

R

NN

O

R

O

OH O

R

OOH

X

X

Y

NN

O

R

O

O

R

O

X

X

Y

Y

NN

O

R

O

O

R

O

X

X

Y

Y

71-88%Y

p-TsOH/ TolueneReflux

76-96%63-71%

X = H, OCH3,Y = H, OCH3, CNR = n-C8H17, p-(C6H13O)Ph

Benzene, N2

Sulfur/ Ph2O

Reflux/N218h

18


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Substituent

and Solvent Effects on Photophysics

of Anthryl

Diimides

NNR

O

O

O

R

O

X

X

Effect of Solvent on Fluorescence Quantum Yields

R = Octyl R = Aryl R=Aryl, X=OMe R= Aryl, X=CN

Φf

0.0

0.1

0.2

0.3

0.4

Toluene THF Acetone

450 500 550 600 650 700 7500.0

0.2

0.4

0.6

0.8

1.0

1.2

Nor

. PL

(mV)

Wavelength (nm)

Tol CHCl3 EA THF DCE ACE

425 450 475 500 525 5500.0

0.2

0.4

0.6

0.8

1.0

1.2

Nor

. PL

(mV)

Wavelength (nm)

tol Cl3 EA THF DCE ACE ACN

R = Octyl

OC6H13R =

19


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Substituent

and Solvent Effects on the Photophysics

of Diimides

NNR

O

O

O

R

O

X

X

Y

Y

Fluorescence Quantum Yields

R = Octyl R = Aryl X,Y= OMe X= OMe, Y=CN

Φf

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

Toluene THF Acetone

450 500 550 600 650 700 7500.0

0.2

0.4

0.6

0.8

1.0

1.2

Nor

. PL

(mV)

Wavelength (nm)

Tol Cl3 EA THF DCE Ace ACN

500 600 7000.0

0.4

0.8

Nor

. PL

(mV)

Wavelength (nm)

Tol Cl3 EA THF DCE Ace ACN

X, Y = H

X, Y = OMe

20


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Twisting of N-Aryl Group Inhibits Charge Transfer

NNR

O

O

O

R

O

21


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Low Temperature Emission Spectra

450 500 550 6000.0

0.2

0.4

0.6

0.8

1.0

Nor

. PL

(mV)

Wavelength (nm)

DM DP DPO DC

Spectra measured in MeTHF

at 77°K

Reducing temperature:•

Reduces rotational motion

•

Inhibits charge transfer

22


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NN

O

O

R R

O

O

X

X

Steric

and Electronic Effects Regulate Excited State Photophysics

SWLW

e-

Donor R’sPolar Solvents

e-

Acceptor R’sRestricted Rotation

Only SW observed• N-octyl

diimides•

Sterically

crowded N-aryl R’s

• Low temperatures

e-

Donor X’s

e-

Acceptor X’s

Only LW ObservedElectron donating N-aryls

+Electron withdrawing X

+Polar solvents

Dual emissionElectron donating N-aryls

+Electron donating X

OrElectron donating N-aryl

+ Non-polar solvents

23


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Anthracene Diimide

Provides Platform for Charge Transfer Mediated Fluorescent Sensors

NN

O

O

O

O

RR

X

XElectron donors that are tailored to interact with given analyte

Tune absorption and emission

24


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New Anthracene Diimide

Molecular Sensor

• Charge Transfer from NH2

quenches fluorescence•

Protonation

or acetylation

of the NH2 prevents charge transfer, activates fluorescence

• Potential use as:sensor for pH, chemical agents (nerve gas)polymer cure monitoring

Ilhan, Tyson and Meador Chem. Mater. 2004

NN

O

O

Ph

Ph O

O

H2N NH2

NO Fluorescence

NN

O

O

Ph

Ph O

O

+H3N NH3+

H+

Fluorescent

25


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PO

O

O

POCl

O

O

POCl

O

Cl

PCl

S

Cl

POF

O

Sarin

Methylphosphonic dichloride (Cl2)

Dimethylphosphinic chloride (Cl)

Dimethyl methylphosphonate (Me)

Ethyl dichlorothiophosphate (Cl2S)

Diimide

Can Detect Organophosphates

450 500 550 600 650 700 750 8000.0

0.2

0.4

0.6

0.8

1.0

Emis

sion

Inte

nsity

(mV)

Wavelength (nm)

SOCl2

Φ

= 0.12

Cl2

Φ

= 0.19

Cl2

S Φ

= 0.20

Cl Φ

= 0.11

Me Φ

= 0.00

26


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Sensor Effective for Both Liquids and Vapors

27


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Anthracene Diimide

Provides Platform for Charge Transfer Mediated Fluorescent Sensors

NN

O

O

O

O

RR

X

XElectron donors that are tailored to interact with given analyte

Tune absorption and emission

28


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Anthracene Dianhydride

is Key to Tailoring Sensor Specificity

CH3

H3CO

OCO2MeMeO2C

CO2Me

CO2MeMeO2C

MeO2CPh OH

Ph OH

Ph

Ph

MeO2C

MeO2C

CO2Me

CO2Me

hν (Pyrex)

10 eq.C6H6, N2

33%

HCl/Ac2OReflux, 18h

N2

92%

Ph

Ph

HO2C

HO2C

CO2H

CO2H

NaOH/H2O + EtOH

Reflux, 18hN2

93%

Ph

Ph

OO

O

O

O

O

Ac2OReflux, 18h

N2

94%

Enables attachment of substituents to imide N that might be photosensitive, e.g., pyridyl groups

29


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Absorption and Emission Spectra

NN

O

O

O

O

NN

400 500 600 7000.0

0.2

0.4

0.6

0.8

1.0

Wavelength (nm)

Nor

mal

ized

Abs

.

0.0

0.2

0.4

0.6

0.8

1.0

Norm

alized PL

Absorption and Emission Spectra in Toluene and 1,2-Dichloroethane

Φf

= 0.035 in Tolueneτf

= 90ps

30


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Diimide

Fluoresence

Shows Solvatochromic Behavior

Effect of Solvent Polarity on Emission Spectra

Wavelength, nm

450 500 550 600 650 700 750 800

Rel

. Int

ensi

ty

0.0

0.2

0.4

0.6

0.8

1.0

1.2

TolueneChloroformTHFEtCl2

400 nm excitation

31


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Stern Volmer Quenching with 2,4-DNT

[Q], M

0.00 0.01 0.02 0.03 0.04 0.05 0.06

I 0/I

0.8

1.0

1.2

1.4

1.6

1.8

Diimide

Fluorescence Quenched by Nitroaromatics

Excited state charge transfer from dye to nitroaromatics

quenches fluorescence

500 550 600 650 700 750 8000

200000

400000

600000

800000

1000000

1200000

1400000

1600000

1800000

PL (m

A)

Wavelength (nm)

0.000 M 0.010 M 0.020 M 0.030 M 0.040 M 0.050 M 0.060 M

32


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Fluorescence Inhibited by Addition of Acids

450 500 550 600 650 700 750 8000

200000

400000

600000

800000

1000000

1200000

1400000

1600000

1800000

PL (c

ps)

Wavelength (nm)

0 1 2 4 8

Addition of TFA protonates

amine and inhibits charge transfer

Excitation at 400 nm

33


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Aggregate Formation in Solid State is Evident in X-Ray

34


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Increased Loading Levels Lead to Red Shifted Emission

Emission Spectra in Polystyrene

Wavelength, nm

400 450 500 550 600 650 700 750 800

Rel

. Int

ensi

ty

0.0

0.2

0.4

0.6

0.8

1.0

1.2

0.1 weight %0.5 weifght %

Suggests formation of dye aggregates in the polymer

35


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TPAA Doped Films Exhibit Thermochromic Behavior

Effect of Temperature on Emission Spectra of Dye Doped LLDPE

Wavelength, nm

400 450 500 550 600 650 700 750 800

Rel

. Int

ensi

ty

0.0

0.2

0.4

0.6

0.8

1.0

1.2

25oC51oC87oC121oC153oC

• Aggregation disrupted at higher temperatures –

blue shift• Process is reversible

36


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Mechanochromic

and Themochromic

Polymers

Crenshaw, B.R. and Weder, C. Macromolecules 2003, 15, 4717-24

H3CO

CN

OCH3

OCH3

CN

OCH3

H3CO

CNCN

OCH3

O

CN

OCH3

OCH3

CN

O

BCMDBBCMB

BCEDB

Stretched Films of 0.18 wt. % BCMDB and BCMB in LLPE

PL Spectra of 0.2 wt. % BCDMB/LLPE Film as a Function of Temperature

37


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Polymer Films and Nanowires

for Field Effect Transistors

106

104

102

100

10-2

10-4

10-6

10-8

10-10

10-12

10-14

10-16

Ag, Cu Fe Mg

In, Sn

Ge

Si

AgBr

Glass

Diamond

Nylon

Quartz

INSU

LATO

RS

SEM

ICO

ND

UC

TOR

S M

ETA

LS

INC

REA

SIN

G D

OPI

NG

LEV

ELS

S/cm

Doped trans-(CH)x[105 S/cm]

Doped polyaniline [103 S/cm]

trans-(CH)x[10-5 S/cm]

Polyaniline[10-10 S/cm]

VS-D (volts)

-1.0-0.8-0.6-0.4-0.20.0

I S-D (n

A)

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

VG

- 20 V

0 V

+ 10 V

+ 20 V

+ 30 V

VS-D (volts)-5-4-3-2-10

I S-D

(nA

)

-20

-15

-10

-5

0

Au SiO2

Au

Nanofiber

5 mμ

Applications:•Small size, power-efficient flexible electronic circuitry for space exploration applications•Communications and data storage circuitry that can be interwoven

into clothing and other surfaces

•Active matrix light emitting diodes, RF identification cards

Technology development requiresinterdisciplinary collaboration

Nano-metrology

DeviceCharacterization

MaterialsOptimization

AFM image of polyaniline/polyethylene nanofiber

Current-

voltage characteristics of nanofiber FET

SEM image of nanofiber Deposited on metallized

SiO2

/Si substrate

Point of Contact:Dr. Félix A. Miranda, RCA216-433-6589

The electrical conductivity ofbulk polyaniline can be variedFrom 10-10

to 6x103

siemens per centimeter

Antenna, Microwave and Optical Systems Branch (RCA); Polymers Branch (RMP)

38


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Electrospun Pentacene/PEO Fiber (vacuum)20 August 2007

VDS (V)

-60 -50 -40 -30 -20 -10 0

I (pA

)

-80

-60

-40

-20

0

20

0V-10V-20V-30V-40V

Pentacene/PEO nanofibers

grown by Prof. Nicholas Pinto, U of Puerto Rico-

Humacao

Pentacene/PEO Nanofiber

FETs

39


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Twistacenes Wudl, F. et al Org. Lett. 2003, 5, 4433-36

•

Addition of pendant phenyls adds steric

bulk-enhances photooxidative

stability, prevents quenching

•

Addition of perylene

endgroups

enhances Φf

40


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Twistacenes

Effect of added TBH on intensity of PL and EL of poly(fluorene

films)

C8H17C8H17

Xu, Q.; Duong, H.M.; Wudl, F.; Yang, Y. Appl. Phys. Lett. 2004, 85, 3357-59

41


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Beyond Anthracenes

and Perylenes

•

Increasing number of benzene rings (conjugation) makes the molecule more polarizable

•

Adding pendant groups improves stability and solid state fluorescence efficiency

•

Flexible chemistry enables tailoring of electronic properties

•

Potential for use in photovolatics, molecular electronics and photonics

CH3

O

Ph

H3CO

Ph

Ph Ph

Ph Ph

NN

O

O

O

O

R R

Ph

Ph

N

N

O

O

R

O

O

R

Ph

Ph

N

N

O

O

R

O

OR

N

N

Ph

Ph

O

O

O

O

R

R

Ph

PhPh

PhN N

NN

O R R O

OO

O

OO

O

R R

N

N N

O

O

R

O

O

R

O

R O

NOR

O Ph

Ph

Ph

Ph

42


www.nasa.gov

Summary

•

Developed new route to highly substituted aryl diimides–

Anthracenes–

Perylenes–

Pyrenes–

Higher homologues•

Exploited excited state behavior to develop fluorescent sensors–

Chemical species–

Warfare agents–

Temperature•

Incorporation of these dyes into polymers has the potential for making “smart”

films, fibers, and

composites

43


www.nasa.gov

Acknowledgements

•

NASA Undergraduate Student Research Program•

NASA Grant NNC07BA13B

•

Funding from the Fundamental Aeronautics Program and the Glenn Innovative Research and Development Fund

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