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7. Luminescent Materials - FH Münster · PDF file7. Luminescent Materials Content ......
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Chapter Luminescent MaterialsSlide 1
Incoherent Light SourcesProf. Dr. T. Jüstel
7. Luminescent MaterialsContent
7.1 History7.2 Definition and Working Principle7.3 Luminescence Mechanisms7.4 Chemical Composition7.5 Composition and Function7.6 Application Areas7.7 Broadband Phosphors7.8 Line Phosphors7.9 UV-A Phosphors7.10 UV-B Phosphors7.11 UV-C Phosphors7.12 IR-A Phosphors
Cd(S,Se) Quantum dots
Chapter Luminescent MaterialsSlide 2
Incoherent Light SourcesProf. Dr. T. Jüstel
7.1 HistorySome milestones
• Stone of Bologna: Barit (Galilei 1600)• Discovery of phosphors (phosphorescence) (Brand 1669)• First phosphor by reaction of shells with sulfur (Canton 1768)• Application of a phosphor in combination with a Hg-discharge (Becquerel 1859)• Patent on the use of CaWO4 in fluorescent lamps (Edison 1896)• Fluorescent lamps with MgWO4 + (Zn,Be)2SiO4:Mn (GE 1938)• Development of Ca5(PO4)3(F,Cl):Sb,Mn (McKeag 1942)• ZnS:Ag, (Zn,Be)2SiO4:Mn and Zn3(PO4)2:Mn for first color CRT (1958)• Fluorescent lamps with Eu- and Tb- phosphors (Verstegen 1974)• First oxidic afterglow pigment SrAl2O4:Eu,Dy (Nemoto 1993)• Nitride phosphors (Schnick 1995)• Transparent ceramics converter for LEDs (Philips 2007)• Narrow band red nitride phosphor Sr[LiAl3N4]:Eu (Schnick 2014)
Chapter Luminescent MaterialsSlide 3
Incoherent Light SourcesProf. Dr. T. Jüstel
7.2 Definition and Working PrincipleDefinitionA phosphor is a micro-or nanoscale pigment, that after excitation by radiation(NIR-,VIS-, UV-, X-ray-, gamma-), high-energy particles or matter vibrations (phonons), emits electromagnetic radiation beyond thermal equilibrium.
When excited by electrons or UV radiation
In daylight
Chapter Luminescent MaterialsSlide 4
Incoherent Light SourcesProf. Dr. T. Jüstel
7.2 Definition and Working PrincipleWorking principle1. Excitation: Absorption of energy from an external source2. Energy transfer: To activator ions (luminescence) or defects (storage)3. Relaxation : Radiative: Emission (luminescence) Luminescent pigm.
Non-radiative: Heat (phonons) Pigment
SEM image of (Y,Gd)BO3:Eu
Typical particle size 1 - 10 µm
Excitation Source
EmissionHeatHeat
SET
D
Emission
A
A A
Heat
Heat
ETET
ET
Heat
Chapter Luminescent MaterialsSlide 5
Incoherent Light SourcesProf. Dr. T. Jüstel
7.3 Luminescence MechanismsTyp Physical process (time scale)Fluorescence Spin-allowed transition (ns - µs)Phosphorescence Spin-forbidden transition (ms)Afterglow (pers. luminescence) Thermal activation of charge carriers (s)
Typ Excitation source Applications Photoluminescence UV photons Fluorescent lamps X-rays luminescence X-rays X-rays intensifierCathodoluminescence Electrons TVs, monitorsElectroluminescence Electric field LEDs, EL displaysThermoluminescence Heat Age determinationChemiluminescence Chemical reaction Emergency signalsBioluminescence Biochemical reaction Fireflies, jellyfishSonoluminescence Ultrasound -Mechanoluminescence Mechanical energy -
Chapter Luminescent MaterialsSlide 6
Incoherent Light SourcesProf. Dr. T. Jüstel
Organic phosphors• Usually aromatic compounds
with extended -electron systems• Examples: Perylenes, coumarines• Low phonon frequency
Inorganic phosphors• Host material + Dopants• Dopants = Activators + Sensitizers + Impurities• Defects = 0-Dim., 1-Dim., 2-Dim., 3-Dim.• Example: (La,Ce,Tb)PO4 = LaPO4:Ce,Tb
Ce,Tb:LaPO4 = La1-x-yCexTby(PO4)
7.4 Chemical Composition
N N
O
O
O
O
O O
OO
Chapter Luminescent MaterialsSlide 7
Incoherent Light SourcesProf. Dr. T. Jüstel
7.4 Chemical CompositionComposition Host material + Dopants + Defects + Impurities
Dopants = Activator/ Sensitizers = RE-, TM- and s2-ions
La57Y
39Sc
21
Hf72Zr
40Ti
22
Ta73Nb41V
23
W74Mo42Cr
24
Re75Tc43Mn25
Os76Ru44Fe
26
Ir77Rh45Co27
Pt78Pd46Ni
28
Au79
Ag47Cu
29
Hg80
Cd48Zn30
Tl81
In49Ga31Al
13B
5
Ba
Be4
Cs55Rb37K
19Na11Li3ZnH
1
Pb82
Sn50Ge
32Si
14C
6
84Te
52Se34S
16O
8
Bi83
Sb51As
33P
15N
7
At85I
53Br
35Cl
17F
9
Rn86Xe54Kr36Ar18Ne10ZnHe2
Po
Ce58
Pr59
Nd60
Pm61
Sm62
Eu63
Gd64
Tb65
Dy66
Ho67
Er68
Tm69
Yb70
Lu71
Th90
Pa91
U92
Np93
Pu94
Am95
Cm96
Bk97
Cf98
Es99
Fm100
Md101
No102
Lr103
1
Ac89
RaFr87
2
3 4 5 6 7 8 9 10 11 12
13 14 15 16 17
18
1
2
3
4
5
6
7
Mg12
Ca20
Sr38
56
88
6
7
Rf104
Db105
Sg106
Bh107
Hs108
Mt109
Ds110
Rg111
Cn112
Chapter Luminescent MaterialsSlide 8
Incoherent Light SourcesProf. Dr. T. Jüstel
Activator Host material Emission at [nm] Color Applications
Mn2+ Zn2SiO4 (Willemit)BaMgAl10O17 (ß-Alumina)
525515
GreenGreen
PDPs, CRTsPDPs, FLs
Mn2+/Sb3+ Ca5(PO4)3(Cl,F) (Halophosphat) 480, 580 White FLs
Mn4+ Mg4GeO5.5F 655 Red Hg high-pressure lamps
Fe3+ LiAlO2 735 Red FLs
Cu+ ZnS 530 Green CRTs
Ag+ ZnS 450 Blue CRTs
Sn2+ (Sr,Mg)3(PO4)2 630 Red Hg high-pressure lamps
Sb3+ (Sr,Ca)5(PO4)3(Cl,F) 480 Blue-Green FLs
Tl+ NaICsI
415560
BlueYellow
x/-ray detectorsx/-ray detectors
Pb2+ BaSi2O5 (Sanbornit)Sr2MgSi2O7 (Akermanit)
350365
UV-AUV-A
FLs for tanning
Bi3+ Bi4Ge3O12 480 Blue-Green x/-ray detectors
7.5 Composition and FunctionComposition: Preparation listed by the activator (trans. metal and s2-ions)
Chapter Luminescent MaterialsSlide 9
Incoherent Light SourcesProf. Dr. T. Jüstel
Activator Host material Emission at (nm) Color Applications
Ce3+LaPO4
YPO4
Y3Al5O12
320335, 355
560
UV-BUV-AYellow
FLs for tanningFLs for tanningFLs, LEDs
Pr3+ Gd2O2SCaTiO3
510610
GreenRed
CT ScannerFEDs
Sm3+ Y3Al5O12 (Granat) 620 Red LASER
Eu2+SrB4O7
BaMgAl10O17
Sr4Al14O25
368453490
UV-ABlueBlue-green
FLs for tanningFLs, PDPsFLs
Eu3+ Y2O3
YVO4
611615
RedRed
FLsHg high-pressure lamps
Gd3+ (La,Bi)B3O6 311 UV-B FLs for medical skin treat.
Tb3+ LaPO4
CeMgAl11O19
(Gd,Ce)MgB5O10
544544544
GreenGreenGreen
FLsFLsFLs
Yb2+ SrSi2N2O2 620 Red -
7.5 Composition and FunctionComposition: Preparation listed by the activator (trans. metal and s2-ions)
Chapter Luminescent MaterialsSlide 10
Incoherent Light SourcesProf. Dr. T. Jüstel
7.6 Application AreasApplication in Excitation sourceCathode ray tubes ElectronsX-rays intensifier X-rays Plasma screens 147, 172 nmXe-discharge lamps 172 nmHg-high pressure discharge lamps 200 – 350 nmHg-low pressure discharge lamps 185, 254 nmEmissive LCDs 370 – 400 nmpcLEDs 370 – 480 nm
Main application areas: lighting, imaging, detection
Excitation energy
Host lattice A
ctivator
Chapter Luminescent MaterialsSlide 11
Incoherent Light SourcesProf. Dr. T. Jüstel
7.6 Application AreasTV
Fluorescent lamps
Plasma TVs
Electroluminescentscreens
LEDs
Tomography
Chapter Luminescent MaterialsSlide 12
Incoherent Light SourcesProf. Dr. T. Jüstel
7.6 Application AreasFunction Application fieldOptical brighteners Paint, paper, clothing, detergentCopy protection Banknotes, stamps, credit cards,
certificate, ticketsProduct protection Pharmaceuticals, plasticsSecurity labeling Emergency exit lighting, emergency exitsAdvertising / visualization Discharge lamps, logosConversion of high-energy radiation or particles
X-ray films, CTs, positron emission tomography, EUV-amplifier
Cosmetics Dental ceramics, tanning lampsMarker for the analysis Detection of nucleic acids + proteinsLithographie PhotocopierPhotochemistry and biology Water purification, disinfection, breeding
boxes and cabinets, air pollution controlMedicine Diagnostics, photodynamic therapy
Chapter Luminescent MaterialsSlide 13
Incoherent Light SourcesProf. Dr. T. Jüstel
7.7 Broadband PhosphorsOptical transitions• Charge-Transfer• 5s-5p, 6s-6p• 4f-5d • 3d-3d
Suitable activators• VO4
3-, WO42-
• Sn2+, Sb3+, Bi3+, Pb2+
• Ce3+, Eu2+
• Mn2+
Examples• (Zn,Be)2SiO4:Mn Willemite• CaWO4 Scheelite• MgWO4 Wolframite• Ca5(PO4)3(F,Cl):Sb,Mn Apatite
FWH
M
300 350 400 450 500 550 600 650 700 750 8000,0
0,2
0,4
0,6
0,8
1,0 MgWO4 CaWO4
Em
issi
on in
tens
ity [a
.u.]
Wavelength [nm]
Chapter Luminescent MaterialsSlide 14
Incoherent Light SourcesProf. Dr. T. Jüstel
7.8 Line PhosphorsOptical transitions• 4f-4f (Sm3+, Eu3+, Tb3+, Er3+, Dy3+, Tm3+)• Very low electron-phonon coupling• Lines or line multiplets
LaPO4:TmYBO3:Tm
Y2O3:Eu(Y,Gd)BO3:EuYVO4:Eu
LaPO4:Ce,TbLaMgB5O10;Ce,TbLaMgAl11O19:Ce,Tb
400 450 500 550 600 650 700 750 8000,0
0,2
0,4
0,6
Em
issi
on in
tens
ity [a
.u.]
Wavelength [nm]
400 500 600 700 8000,0
0,2
0,4
0,6
0,8
1,0
Em
issi
on in
tens
ity [a
.u.]
Wavelength [nm]
400 500 600 700 8000,0
0,2
0,4
0,6
0,8
1,0
Em
issi
on in
tens
ity [a
.u.]
Wavelength [nm]
Chapter Luminescent MaterialsSlide 15
Incoherent Light SourcesProf. Dr. T. Jüstel
7.9 UV-A PhosphorsOptical transitions• 4f-5d• 6s-6p
Suitable activators• Eu2+ (>365 nm)• Ce3+
• Pb2+
Commercial materials• LaMgAl11O19:Ce 345 nm Magnetoplumbite• YPO4:Ce 335, 355 nm Xenotime• BaSi2O5:Pb 350 nm Sanbornit• Sr2MgSi2O7:Pb 365 nm Akermanite• SrB4O7:Eu 368 nm
280 300 320 340 360 380 400 420 440 4600,0
0,2
0,4
0,6
0,8
1,0
YPO4:Ce
LaMgAl11O19:Ce
Em
issi
on in
tens
ity [a
.u.]
BaSi2O5:PbSrB4O7:Eu
Sr2MgSi2O7:Pb
Wavelength [nm]
Chapter Luminescent MaterialsSlide 16
Incoherent Light SourcesProf. Dr. T. Jüstel
7.10 UV-B PhosphorsOptical transitions• 4f-5d• 4f-4f• 6s-6p
Suitable activators• Ce3+
• Bi3+
• Gd3+ (311 nm)
Commercial materials• SrAl12O19:Ce 300 nm Magnetoplumbite• LaB3O6:Bi,Gd 311 nm (Bi3+ Gd3+ energy transfer)• LaPO4:Ce 320 nm Monazite
260 280 300 320 340 360 380 400 420 4400,0
0,2
0,4
0,6
0,8
1,0LaB3O6:Bi,Gd
Em
issi
on in
tens
ity [a
.u.]
LaPO4:CeSrAl12O19:Ce
Wavelength [nm]
Chapter Luminescent MaterialsSlide 17
Incoherent Light SourcesProf. Dr. T. Jüstel
7.11 UV-C PhosphorsOptical transitions• 4f-5d• 6s-6p
Suitable activators• Pr3+
• Bi3+
• Pb2+
Examples• YBO3:Pr 265 nm Vaterite• YAlO3:Pr 245 nm Perovskite• YPO4:Bi 240 nm Xenotime• CaSO4:Pb 230 nm Anhydrite
200 250 300 3500,0
0,2
0,4
0,6
0,8
1,0
YBO3:Pr
Em
issi
on in
tens
ity [a
.u.]
CaSO4:Pb YPO4:Bi
Wavelength [nm]
Chapter Luminescent MaterialsSlide 18
Incoherent Light SourcesProf. Dr. T. Jüstel
7.12 IR-A PhosphorsOptical transitions• 3d-3d• 4f-4f
Suitable activators• Cr3+ 680 – 750 nm• Fe3+ 700 – 800 nm• Nd3+ ~ 1060 nm• Yb3+ ~ 950 - 1050 nm
Examples• Al2O3:Cr 694 nm Corundum → Ruby laser• LiAlO2:Fe 735 nm - → Fluorescent lamps• Y3Al5O12:Nd 1064 nm Garnet → YAG:Nd-laser• Y3Al5O12:Yb 1028 nm Garnet → YAG:Yb-laser
200 400 600 800 1000 1200 1400 16000,0
0,2
0,4
0,6
0,8
1,0
Sample: Y3Al5O12:Nd
Rel
ativ
e in
tens
ity
Wavelength [nm]
Y3Al5O12:Nd