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Recent Developments onRecent Developments on UV Emitting Phosphors
Thomas Jüstel
[email protected]://www.fh-muenster.de/fb1/personal/professoren/juestel/Juestel.phphttps://www.fh muenster.de/fb1/personal/professoren/juestel/Juestel.php
8th Phosphor Global SummitSan Diego, CA
Prof. Dr. T. Jüstel, University of Applied Sciences Münster, Germany Slide 1
g ,March 25th, 2010
OutlineOutline
1 Application Areas of UV Radiation1. Application Areas of UV Radiation
2. UV Radiation Sources
3. UV Emitting Phosphors
4. Efficiency of UV Emitting Phosphors
5 Thermal Q enching and VUV Stabilit5. Thermal Quenching and VUV Stability
6. Conclusions and Future Trends
Prof. Dr. T. Jüstel, University of Applied Sciences Münster, Germany Slide 2
1. Application Areas of UV Radiation1. Application Areas of UV Radiation
100 nm 200 nm 280 nm 320 nm 400 nm
UV-B UV-AUV-CVUV
100 nm 200 nm 280 nm 320 nm 400 nm12.5 - 6.9 eV 6.2 – 4.5 eV 4.5 - 3.9 eV 3.9 – 3.1 eV
Cleavage of H2O and O2i t di l
Excitation of C=C bonds Vitamine D3 production Photocatalytic reactionsinto radicals
Ozone formation
Cleavage of C C C H C O
Excitation of nucleobasesand tryptophane
Transcription of repairenzymes
M l f ti
Melanine oxidation(skin)
Cleavage of C-C, C-H, C-O bonds
Cleavage of O3, ClO2 and H2O2
Conversion of NO3- to NO2
-
Melanosome formation(skin)
Decomposition of organic pigments
Activation of h t t l ti l i tphotocatalytical pigments
• Waver cleaning
• Photochemistry
• Disinfection of air, H2O and surfaces
• Treatment of skindiseases, e.g. psoriasis
• Water and air purification@ TiO2 photocatalyst, formation of OH. and O2
.
radicals• Photochemistry • Tanning
• Photochemistry
radicals
• Tanning
Photochemistry
Prof. Dr. T. Jüstel, University of Applied Sciences Münster, Germany Slide 3
• Photochemistry
1. Application Areas of UV Radiation1. Application Areas of UV RadiationPhotochemistry - Water on air components1. Photochemical cleavage of waterH2O + h(< 200 nm) OH. + H.
2 OH. H2O22 H2O2 2 H2O +1O2
2. Ozone formationO2 + h(< 200 nm) 2 O.
2 O2 + 2 O. 2 O3
3. Photochemical cleavage of ozoneO3 + h(< 320 nm) O2 + 1O
4. Photochemical cleavage of carbon dioxidegCO2 + h(< 200 nm) CO + O.
5. Cleavage of N2 and subsequent NO formation
240 nm
Prof. Dr. T. Jüstel, University of Applied Sciences Münster, Germany Slide 4
5. Cleavage of N2 and subsequent NO formationN2 + h(< 120 nm) 2 N. 2 N + O2 2 NO
1. Application Areas of UV RadiationPhotochemistry - Effect on O3 and H2O2
1. Application Areas of UV Radiation
1. Cleavage of OzoneO3 + H2O + h(< 330 nm) H2O2 + O2
O3 + h(< 300 nm) O2 + O.
O. + H2O 2 OH.
2. Cleavage of Hydrogen PeroxideH O + h (< 280 ) 2 OHH2O2 + h(< 280 nm) 2 OH.
OH. radicals are the key to Advanced Oxidation Processes (AOPs)OH. + M OH- + M+
Decomposition of organic compounds in air water and @ surfaces
Prof. Dr. T. Jüstel, University of Applied Sciences Münster, Germany Slide 5
Decomposition of organic compounds in air, water and @ surfaces
1. Application Areas of UV RadiationPhotochemistry – Electrocyclic reactions
[2 2] l dditi ibl f DNA d di i f ti
1. Application Areas of UV Radiation
e.g. [2+2] cycloaddition → responsible for DNA damage → disinfection
1,0 Disinfection efficiency (DIn 5031-10)
n
2s + 2s
OCN
NCO
O HP0,6
0,8
Absorption spectrum of dTMP
cien
cy/a
bsor
ptio
n
CCCH3H
PO
NCO H
0,2
0,4
Rel
. effi
cNucleotide at 260 nm
P
CCCN
NC O
CH3HO
OCC
CNNC O
H
200 250 300 3500,0
Wavelength [nm]
dAMP 15200 lmol-1cm-1
dTMP 8400 lmol-1cm-1
dGMP 12000 lmol-1cm-1P
OCN
NCO
O H
CCCH3H
Prof. Dr. T. Jüstel, University of Applied Sciences Münster, Germany Slide 6
dCMP 7100 lmol-1cm-1CCCH3H
1. Application Areas of UV Radiation1. Application Areas of UV Radiation21st Century Challenge: Air, Soil, and Water Pollution
6000 AgricultureI d
5000
IndustryHouseholdTotal
n / 1
09m
3
4000
onsu
mpt
ion
3000
• UV-C Radiation (260 nm) inactivates micro- Wat
er c
o
2000
organisms due to DNA photochemistry• VUV Radiation (180 nm) oxidizes due to
H2O cleavage and OH. And O2.- formation
Industrial installations → discharge lamps
1000
Prof. Dr. T. Jüstel, University of Applied Sciences Münster, Germany Slide 77
Industrial installations → discharge lampsMobile devices → discharge lamps / diodes 0
1900 1950 2000 2050Year
2. Types of UV Radiation SourcesSun > 300 nm
Hg discharge lamps
2. Types of UV Radiation Sources1,0 UV-AUV-B
m-1]
Solar UV spectrum
Hg discharge lamps• low pressure 185, 254 nm• amalgam 185, 254 nm• medium pressure 200 – 400 nm 0,4
0,6
0,8
al ir
radi
ance
[Wm
-2n
p
Xe/(Hg) discharge lamps 230 – 800 nm
D discharge lamps 110 400 nm280 300 320 340 360 380 400
0,0
0,2
Spe
ctra
Wavelength [nm]
Solar radiationat 60° sun height(clear sky)
D2 discharge lamps 110 – 400 nm
Excimer LASER• ArF* 193 nm
Medium pressure Hg lamps
1,0
1,2
y
Excimer lamps• Xe2* 172 nm• KrCl* 222 nm 0 4
0,6
0,8
mal
ised
Inte
nsity
• KrCl 222 nm• XeBr* 282 nm• XeCl* 308 nm
200 220 240 260 280 300 320 3400,0
0,2
0,4
Nor
m
Wavelength [nm]
Prof. Dr. T. Jüstel, University of Applied Sciences Münster, Germany Slide 8
(Al,Ga)N LEDs 210 – 370 nm
2. Types of UV Radiation Sources
147 172150
2. Types of UV Radiation SourcesPhilips Patent
DE 199 19 169 7
Desired lampspectrum
147 172Resonance
Intensity
1stC
ontinu
150
2ndC
ontin
DE 199 19 169.7
spectrum
Wavelength [nm]
e Line
y[a.u.]
uum
nuum
Features
(quartz) glassWavelength [nm]
Application areas Phosphor layer
Phosphor layer
Features– Discharge efficiency ~ 65%
(elaborated driving scheme)– Hg free
Application areas Phosphor layer– Plasma displays RGB– Copier lamps RGB or B/W– LCD Backlighting RGBg
– Fast switching cycles– Temperature independent– Dimmable
LCD Backlighting RGB– Medical skin treatment UV-A/ or UV-B– Disinfection UV-C– Ultra pure water VUV
Prof. Dr. T. Jüstel, University of Applied Sciences Münster, Germany Slide 9
– Main emission band at 172 nm (VUV)p
– Surface/wafer cleaning VUV
3. UV Emitting Phosphors3. UV Emitting PhosphorsHost lattices and activators ions
100 nm 200 nm 280 nm 320 nm 400 nm
UV-B UV-AUV-CVUV
Host lattices
Fluorides Phosphates Borates Silicates Aluminates
Activator ions
Nd3+NdPb2+, Pr3+, Bi3+
Gd3+, Bi3+, Pr3+, Ce3+
Tm3+ , Pb2+, Ce3+
Prof. Dr. T. Jüstel, University of Applied Sciences Münster, Germany Slide 1010
Tm , Pb , Ce
3. UV Emitting Phosphors1S0 – 2S+1LJ line emissionYF3:Pr NaYF4:Pr
Pr3+ - Tuning its emission spectrum3. UV Emitting Phosphors
213, 236
EnergyNaYF4:Pr
SrAl12O19:PrLaMgB5O10:PrLaB3O6:Pr
UV band emission
UV li i i
213, 236252, 271407 nm
y of thelow
1S0 – 2S+1LJ line and 4f15d1 – 4f2 band em.KY3F10:Pr 240, 250, 271 nm
4f15d1 4f2 b d i iBlue emission
UV line emission
westcryst
4f15d1 – 4f2 band emissionLiYF4:Pr 218 nmYPO4:Pr 232 nmKYF4:Pr 235 nm
tal-fieldco
YAlO3:Pr 245 nmYBO3:Pr 263 nmLu2Si2O7:Pr 273 nmLu3Al5O12:Pr 310 nm
Red emission
omponent
1D2
Lu3Al5O12:Pr 310 nmY3Al5O12:Pr 320 nm
1D2- 3HJ line emissionY2O3:Pr 615 nm
of [Xe]4f 1
Prof. Dr. T. Jüstel, University of Applied Sciences Münster, Germany Slide 11
Y2O3:Pr 615 nmCaTIO3:Pr,Na 615 nm
5d1
3. UV Emitting PhosphorsPr3+ doped fluorides: [Xe]4f15d1 – [Xe]4f2 vs. [Xe]4f2 – [Xe]4f2 emission
1,0KY3F10:Pr3+
3. UV Emitting Phosphors
NaYF4:Pr3+ 252, 271 nm hexagonal CN9KY3F10:Pr3+ 240, 250, 271 nm cubic CN8LiYF4:Pr3+ 218, 228 nm tetragonal CN8 0,6
0,8
[a.u
.]
Emission bei 160 nm Anregung bei 250 nm Reflexion
KYF4:Pr3+ 235 nm hexagonal CN7
0,2
0,4
Inte
nsity
[
200 300 400 500 600 700 8000,0
Wavelength [nm]
1,0KYF4:Pr3+
E i i b i 160
1,0NaYF4:Pr3+
1,0 Excitation spectrum
Em
= 219 nm; Grating 2400 lines/mm
LiYF4:Pr3+
0,6
0,8
ity [a
.u.]
Emission bei 160 nm Anregung bei 232 nm Reflexion
0,6
0,8
ity [a
.u.]
Emission bei 160 nm Anregung bei 272 nm Reflexion
0,6
0,8Em
; gslit size: Ex = 0.50 mm, Em = 4.00 nm
Emission spectrum
Ex= 160 nm; Grating 1200 lines/mm
slit sizes: Ex = 1.50 mm, Em = 0.5 nm
sity
(a.u
.)
0,2
0,4
Inte
ns
0 0
0,2
0,4
Inte
ns
0,0
0,2
0,4
Inte
ns
Prof. Dr. T. Jüstel, University of Applied Sciences Münster, Germany Slide 12
200 300 400 500 600 700 8000,0
Wavelength [nm]200 300 400 500 600 700 800
0,0
Wavelength [nm]
100 200 300 400 500 600 700 800,
Wavelength [nm]
3. UV Emitting Phosphors3. UV Emitting PhosphorsPr3+ doped garnets: [Xe]4f15d1 – [Xe]4f2 vs. [Xe]4f2 – [Xe]4f2 emission
Emission and excitation spectra of
Lu3Al5O12:Pr3+ Y3Al5O12:Pr3+Lu3Al5O12:Pr Y3Al5O12:Pr
1,0
Emission spectrum Excitation spectrum
160 nm exc.max = 309 nm
1,0 Emission spectrum Excitation spectrum
160 nm excitation
0,6
0,8
nten
sity
centroid = 344 nm
0,6
0,8
nten
sity
0,2
0,4
Rel
ativ
e in
0,2
0,4
Rel
ativ
e i
100 200 300 400 500 600 700 8000,0
0,2
Wavelength [nm]100 200 300 400 500 600 700 800
0,0
0,2
Wavelength [nm]
Prof. Dr. T. Jüstel, University of Applied Sciences Münster, Germany Slide 13
Wavelength [nm] Wavelength [nm]
3. UV Emitting PhosphorsUV-A Range
Lu3Al5O12:Tm
3. UV Emitting Phosphors
0,8
1,0 YPO4:CeLaMgAl11O19:CeBaSi2O5:Pb
y
0,8
1,0 Emission spectrum LuAG:Tm 1700°C Excitation spectrum LuAG:Tm 1700°C Reflection spectrum
3 5 12
0,4
0,6
Rel
ativ
e in
tens
it
0,4
0,6
Rel
ativ
e in
tens
ity
150 200 250 300 3500,0
0,2
Sr2MgSi2O7:Pb
R
172 nm100 200 300 400 500 600 700 800
0,0
0,2
R
Standard UV-A phosphorsVUV Efficiency: LaMgAl11O19:Ce > YPO4:Ce ~ BaSi2O5:Pb > Sr2MgSi2O7:Pb
Wavelength [nm] Wavelength [nm]
Novel UV-A phosphor for Xe excimer discharge lampsLu3Al5O12:Tm Emission @ 292 and 352 nm, excitation maximum at 170 nm
Prof. Dr. T. Jüstel, University of Applied Sciences Münster, Germany Slide 14
3 5 12 @ ,LaPO4:Tm and other Tm3+ doped wide band gap hosts show similar em.
spectra
3. UV Emitting Phosphors3. UV Emitting PhosphorsUV-B Range – Gd3+ activated materials
1,0 6P7/2 ->8S7/2
Band gap ~ 172 nmYAl3(BO3)4:10%Gd
160 nm excitation
Sensitisation by the host lattice (suitable band gap!)
Example: YAl3(BO3)4:Gd3+0,6
0,8
7/2 7/2
ve in
tens
ity
Example: YAl3(BO3)4:Gd(NEC patent US2005/001024)
0 0
0,2
0,4
8S7/2->6IJ
Rel
ativ
Sensitisation by co-dopantsBi3+ large lattice site (e.g. La3+) requiredCe3+ suitable 4f5d state pos. required
100 200 300 400 500 600 7000,0
Wavelength [nm]
1,04f2-> 4f15d1
6P 8S
YAl3(BO3)4:10%Gd,1%Pr160 nm excitationp q
Pr3+ suitable 4f5d state pos. requiredNd3+ suitable 4f5d state pos. required
0,6
0,8
6P7/2 ->8S7/2
e in
tens
ity Band gap
Example: YAl3(BO3)4:Gd3+Pr3+
0 0
0,2
0,4
Rel
ativ
e
Prof. Dr. T. Jüstel, University of Applied Sciences Münster, Germany Slide 15
100 200 300 400 500 600 7000,0
Wavelength [nm]
3. UV Emitting PhosphorsUV-B Range – Gd3+ activated materials
3. UV Emitting Phosphors
Example: LaMgAl11O19:Gd3+
0,8
1,0 LO NP806 LO TR037-05 LO TR036-05
lues
]
LaMgAl11O19:Gd vs LaPO4:Ce (NP806)
2,0x105
2,2x105
2,4x105 Emission spectrum NP806 Emission spectrum TR3705 Emission spectrum TR3605
LaMgAl11O19:Gd vs LaPO4:Ce (NP806)
unts
)
0 4
0,6
ut [a
bsol
ute
val
1 0x105
1,2x105
1,4x105
1,6x105
1,8x105
n in
tens
ity (C
ou
0,2
0,4
Ligh
t out
pu
exc.slit 2 x 3000 m
emis.slit 2 x 250 mmonitored at 312 nm(LAP C t 320 )
2,0x104
4,0x104
6,0x104
8,0x104
1,0x10
Em
issi
on exc.slit 2 x 3000 memis.slit 2 x 250 mexcitation at 160 nm
Light output at 172 nm close to 100% (20% higher than that of LaPO :Ce)
150 200 250 300 350 4000,0
(LAP:Ce at 320 nm)
Wavelength [nm]
200 250 300 350 4000,0
Wavelength [nm]
Prof. Dr. T. Jüstel, University of Applied Sciences Münster, Germany Slide 16
Light output at 172 nm close to 100% (20% higher than that of LaPO4:Ce)
3. UV Emitting Phosphors3. UV Emitting PhosphorsUV-B Range – Gd3+ activated Lu3Al5O12 and LnPO4
Lu3Al5O12:Gd3+ GdPO4:Nd3+
1,0
Emission spectrumExcitation spectrum
160 nm exc. 1,0 6P7/2 -8S7/24f3-4f25d1
0 6
0,8
Excitation spectrum
nsity
max
= 311 nm
0 6
0,8
7/2 7/24f 4f 5d
nsity
0,4
0,6
Rel
ativ
e in
ten
0,4
0,6
->6IJ->6GJ
Rel
ativ
e in
ten
100 200 300 400 500 600 700 8000,0
0,2
150 200 250 300 350 400 450 500 550 600 650 700 7500,0
0,2
W l th [ ]
Efficient ET fromthe host lattice to Gd3+
Wavelength [nm] Wavelength [nm]
Efficient ET fromNd3+ to Gd3+
Prof. Dr. T. Jüstel, University of Applied Sciences Münster, Germany Slide 17
3. UV Emitting PhosphorsUV-C Range - Bi3+ or Pb2+ activated materials Ground state config : [Xe]4f145d106s2 Excited state: [Xe]4f145d106s16p1
3. UV Emitting Phosphors
Ground state config.: [Xe]4f145d106s2 Excited state: [Xe]4f145d106s16p1
1,0 DIN5031-10C SO Pb
1,0 DIN5031-10
0,6
0,8
CaSO4:Pb(Ca,Mg)SO4:PbSrSiO3:Pb
nten
sity
0,6
0,8LuPO4:Bi
inte
nsity
YPO4:Bi
0,2
0,4
Nor
mal
ised
i
0,2
0,4
Nor
mal
ised
200 220 240 260 280 300 320 3400,0
Wavelength [nm]
200 220 240 260 280 300 320 3400,0
Wavelength (nm)
(Ca,Mg)SO4:Pb, SrSiO3:Pb sensitivity towards water, Xe up-take
(Y,Lu)PO4:Bi3+ good chemical stability + high VUV efficiency
Prof. Dr. T. Jüstel, University of Applied Sciences Münster, Germany Slide 18
3. UV Emitting PhosphorsUV-C Range - Pr3+ activated materials
3. UV Emitting Phosphors
YPO4:Pr3+ YBO3:Pr3+
1,0 4f2 - 4f15d1 3H4
172 nm1 0
4f15d1 3H4
0,6
0,8
nten
sity
4
3H5
0 6
0,8
1,0
Hostlattice
3H6
3H5
4
0 2
0,4
,
Rel
ativ
e In
3H6 3FJ
Host Lattice
0,4
0,6
3FJ
100 150 200 250 300 350 400
0,0
0,2
Wavelength [nm]100 200 300 400 500
0,0
0,2
Wavelength [nm]
Emission maximum can be tuned between 220 and 320 nm by thet l fi ld litti d l t h t f th h t l tti
g [ ]g [ ]
Prof. Dr. T. Jüstel, University of Applied Sciences Münster, Germany Slide 19
crystal-field splitting and covalent character of the host lattice
3. UV Emitting PhosphorsVUV to VUV down converting phosphors - Nd3+ emitter
3. UV Emitting Phosphors
YPO4:Nd3+ LiYF4:Nd3+
0,8
1,0 Emission spectrum Excitation spectrum
sity
0,8
1,0 Emission spectrum Excitation spectrum
sity
0,4
0,6
mal
ised
int
ens
0,4
0,6
Rel
ativ
e in
tens
120 140 160 180 200 220 240 260 280 300 320 340 360 380 4000,0
0,2Nor
m
120 140 160 180 200 220 240 260 280 300 320 340 360 380 4000,0
0,2
Emission maxima at about 190 + 240 + 278 nm due tointerconfigurational [Xe]4f25d1 to [Xe]4f3(4IJ, 4GJ, 4FJ) transitions
Wavelength (nm) Wavelength [nm]
Prof. Dr. T. Jüstel, University of Applied Sciences Münster, Germany Slide 20
J J J
20
4. Efficiency of UV PhosphorsConversion efficiency as product of quantum efficiency and absorption
y p
Phosphor exc. band max. em. band max. QY @ 172 nm YPO4:Nd 160, 190 nm 190 nm 90%LaPO4:Pr 165, 200 nm 225 nm 70%YPO4:Pr 160, 190 nm 233 nm 70%YPO4:Bi 170 nm 241 nm 90%(C M )SO Pb 170 245 80%(Ca,Mg)SO4:Pb 170 nm 245 nm 80%LuBO3:Pr 240 nm 257 nm 50%YBO3:Pr 240 nm 261 nm 50%Y SiO :Pr 170 245 nm 270 nm 20%Y2SiO5:Pr 170, 245 nm 270 nm 20%SrSiO3:Pb 170, 235 nm 275 nm 80%LaMgAl11O19:Gd 170, 275 nm 311 nm 95%LaPO :Ce 170 270 nm 320 nm 90%LaPO4:Ce 170, 270 nm 320 nm 90%YPO4:Ce 170, 270 nm 335, 355 nm 55%LaMgAl11O19:Ce 170, 275 nm 340 nm 90%
Prof. Dr. T. Jüstel, University of Applied Sciences Münster, Germany Slide 21
4. Efficiency of UV Phosphorsy pPhosphor converted Xe2* excimer discharge lamp for disinfection
1,0 Germicidal Action Curve
Requires development of UV-C emitting
phosphors with a high conversion efficiency 0,6
0,8
nsity
(a.u
.)
Lamp spectrum of YAlO3:Pr
and a large integral overlap with GAC
e.g. Pr3+ or Bi3+ activated materials0,2
0,4
Em
issi
on in
te
Phosphor max [nm] GAC overlap [%]YPO4:Pr 233 78
200 250 300 350 4000,0
Wavelength [nm]1,0 Germicidal Action Curve
L S t YBO PYPO4:Pr 233 78YPO4:Bi 241 71YAlO3:Pr 245 71YBO3:Pr 263 61
0,6
0,8
inte
nsity
[a.u
.]
Lamp Spectrum YBO3:Pr
YBO3:Pr 263 61Line @ 265 100Line @ 311 0
0 0
0,2
0,4
Em
issi
on
Prof. Dr. T. Jüstel, University of Applied Sciences Münster, Germany Slide 22
200 250 300 350 4000,0
Wavelength [nm]
5. Thermal Quenching and VUV Stability
0 8
1,0
nsity
120000
140000 YPO4Pr025C YPO4Pr075C YPO4Pr150CYPO4P 200C
s]
g yUV-C Phosphors YPO4:Pr and YPO4:Bi
0,4
0,6
0,8
e em
issi
on in
ten
60000
80000
100000
120000 YPO4Pr200C YPO4Pr250C YPO4Pr300C YPO4Pr330C
on in
tens
ity [C
ount
s
0 50 100 150 200 250 300 3500,0
0,2 Integral Intensity at 233 nm Intensity at 271 nm
Rel
ativ
e
200 250 300 3500
20000
40000
Em
issi
o
YPO4:Pr
Temperature [°C]Wavelength [nm]
0,8
1,0
inte
nsity
200000
300000 UVC0803025C UVC0803075C UVC0803150C UVC0803200CUVC0803250C
y [a
.u.]
0,4
0,6
inte
gral
em
issi
on
100000
200000 UVC0803250C UVC0803300C UVC0803330C
Em
issi
on in
tens
ity
TQ1/2 of both phosphors is beyond 400 °C 0 50 100 150 200 250 300 3500,0
0,2
UVC22/03D UVC13/03A
Rel
ativ
e T t [°C]
90% at 325°C90% at 230°C200 220 240 260 280 300 320
0
Wavelength [nm]
YPO4:Bi
Prof. Dr. T. Jüstel, University of Applied Sciences Münster, Germany Slide 23
TQ1/2 of both phosphors is beyond 400 CEmission band of YPO4:Bi shifts towards 250 nm upon heating
Temperature [°C]
5. Thermal Quenching and VUV Stabilityg yUV-A Phosphor Lu3Al5O12:Tm and UV-B Phosphor Lu3Al5O12:Pr
8,0x104Emission spectra Lu3Al5O12:Tm3+
Ex= 264 nmslit size: Ex = 4 00 Em = 1 00
120000
Emission spectra of Lu3Al5O12:Pr (160 nm Excitation) LED8102025CLED8102075C
4,0x104
6,0x104
slit size: Ex 4.00, Em 1.00 200 K 250 K 300 K 350 K 400 K 450 K 500 K
sity
[cou
nts]
60000
80000
100000 LED8102150C LED8102200C LED8102250C LED8102300C LED8102330C
inte
nsity
[a.u
.]
300 350 400 450 500 5500,0
2,0x104Inte
ns
200 250 300 350 400 450 500 550 600 650 700 750 8000
20000
40000
Em
issi
on
0,8
1,0Emission integral Lu3Al5O12:Tm3+
u.]
Wavelength [nm]
0,7
0,8
0,9Colour Points of Lu3Al5O12:Pr
200 250 300 350 400 450 500 550 600 650 700 750 800
Wavelength [nm]
0,4
0,6
mal
ised
Inte
nsity
[a.u
0,3
0,4
0,5
0,6
330°C
BBL
y
25°C
Phosphors does not show significant quenching up to 250 °C250 300 350 400 450 500
0,0
0,2 Emission Integral
Ex= 264 nm
norm
Temperature [K]
0,0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,80,0
0,1
0,2BBL
x
Prof. Dr. T. Jüstel, University of Applied Sciences Münster, Germany Slide 24
Phosphors does not show significant quenching up to 250 C, but strong change of spectral power distribution, resulting in a red-shift
5. Thermal Quenching and VUV Stabilityg yPr3+ doped fluoride and garnet in Xe excimer discharge lamps
110
90100110
nsity
708090
ve in
ten
405060
Rel
ativ
400 100 200 300 400
t [h]
Fluorides show severe degradation
t [h]
Prof. Dr. T. Jüstel, University of Applied Sciences Münster, Germany Slide 25
Garnets are impressively stable!
6. Conclusions and Future Trends6. Conclusions and Future TrendsHg low-pressure lamps
S t f UV A d UV B h h ll t bli h d• Set of UV-A and UV-B phosphors well established• Degradation due to Hg consumption and phosphor damage limits lifetime to
less than about 1000 h
Xe excimer discharge lamps
• Arbitrary UV spectra feasible • UV-A phosphor with a high VUV efficiency is LaMgAl11O19:Ce• Gd3+ activated UV-B phosphors can be sensitised by the host lattice, by Nd3+,
or by Bi3+or by Bi3• Lu3Al5O12 is an ideal host lattice for efficient UV emitting phosphors due to
the suitable band gap • YPO4:Bi and YPO4:Nd are the most efficient UV-C and VUV phosphors so far4 4• VUV phosphors compliable with Xe excimer lamps should be derived from
lattices, which are alkaline in character and have a sufficiently wide band gap, e.g. La14Si9O39 or Y9Li(SiO4)6O2
• Novel UV emitting VUV phosphors will enable attractive novel application
Prof. Dr. T. Jüstel, University of Applied Sciences Münster, Germany Slide 26
Novel UV emitting VUV phosphors will enable attractive novel application areas for Xe2* discharge lamps
6. Conclusions and Future Trends6. Conclusions and Future TrendsAlGaN LEDs as UV radiation sources?
Semiconductor Band gap [eV] [nm]GaN 3.5 360 AlN 6.0 210
Status early 2010 (Appl. Phys. Express 3, 031002, 2010)250 nm 1 18% EQE @ 4 8 mW250 nm 1.18% EQE @ 4.8 mW262 nm 1.54% EQE @ 10.4 mW
Development goals (Nichia)Development goals (Nichia)• 365 nm 5 W LEDs • 260 nm “mW” LEDs
Recent patent applications• UV-C LED µ-photo reactors• UV-C LED storage container
Prof. Dr. T. Jüstel, University of Applied Sciences Münster, Germany Slide 27
U C sto age co ta e• UV LED tanning equipment
AcknowledgementAcknowledgement
Many thanks to my co-workers and colleagues:
Dr. Helga BettentrupDavid EnselingDr. Georg GreuelRolf GerdesBenjamin HerdenArturas KatelnikovasJagoda KucDaniel MichalikDr. Julian PlewaTatjana RatProf. Cees RondaSebastian SchwungLisa SiewertHilke Sonntag
Prof. Dr. T. Jüstel, University of Applied Sciences Münster, Germany Slide 28
gDr. Dominik Uhlich
Thanks for your kind attention!
Prof. Dr. T. Jüstel, University of Applied Sciences Münster, Germany Slide 29