7. Luminescent Materials - FH Münster · PDF file7. Luminescent Materials Content ......

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



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)



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



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



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 -



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



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



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)



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)



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



7.6 Application AreasTV

Fluorescent lamps

Plasma TVs

Electroluminescentscreens

LEDs

Tomography



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



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]



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]



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]



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]



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]



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

7. Luminescent Materials - FH Münster · PDF file7. Luminescent Materials Content ......

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