新陶瓷螢光材料於白光發光二極體製作之應用

台灣大學化學系 

台灣大學化學系.材料化學實驗室 



台灣大學化學系材料化學實驗室 

材料化學實驗室 

Materials Chemistry Laboratory 

Department of Chemistry 

National Taiwan University 

陶業學會年會 

陶業學會年會 

New Ceramic Phosphors for LEDs 

Ru-Shi Ru Shi Liu (劉如熹 ( 劉如熹劉如熹) 劉如熹 

劉如熹 


National Taiwan University, Taipei 106, Taiwan 

Shu-Fen Shu Fen Hu (胡淑芬胡淑芬胡淑芬) 胡淑芬 

胡淑芬 

Institute of Electro-optical Science and Technology, 

National Taiwan Normal University, Taipei 116, Taiwan 

5/22/2007 New Ceramic Phosphors for LEDs 1






National Taiwan University Europe, 160KK, 

5% 

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2002.12 2003.6 2003.12 2004.6 2004.12 2005.6 2005.12 2006.6 2006.12 

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Source::::PIDA, 12/2006 

5/22/2007 New Ceramic Phosphors for LEDs 2 

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Outline 

Introduction 

White light emitting diode (LED) 

The developments of oxynitride and phosphate 

phosphors 

The goals of the research 

Experimental,Results and Discussion 

MSi 2N 2O 2 (M: alkaline earth) and KSrPO 4 

Future prospect 








Blue LED + Yellow Phosphor 

(460-480 nm) 

Garnet-based LEDs : prospects & limitations 

Y 3Al 5O 12:Ce 3+ 

(light) 

(YAG:Ce) 

GaN 

The disadvantages of YAG: 

1. Only excitable by blue LED 

2. Cool white 

3. Lower color rendering index 

4. Less thermal stable 








Oxynitride phosphors 

MSi 2N 2O 2 (M: alkaline earth) 








(Oxy)Nitride phosphors-converted WLED 

MSi 2 N 2 O 2 :Eu 

white 

M 2Si 5N 8:Eu 

The advantages of (Oxy)nitride 

( Oxy)nitride : 

• Excitable by UV and 

blue LEDs 

• Warm white 

• Higher color rendering 

index 

• Thermal stable 








Stability : UV or Blue/(Oxy)nitride > Blue/YAG 

E 

5d 

free ion 

Eu 2+ 

4f 

Δ NE 

Δ NE (O) < Δ NE (N) 

(higher covalency) 

Nephelauxetic 

Effect 

Strong crystal field 

formal charge:O 2-







Developments of MSi 2 N 2 O 2 

Osram, Sep 24, 2002 

MSi 2 N 2 O 2 :Eu 2+ 

(M = Ca, Sr, Ba) 

Chem. Mater. 17, 3242 (2005) 

J. Mater. Chem. 21, 396 (2006). 

EuSi 2 N 2 O 2 (Yellow) 

Submission: 1/25/2005 









Developments of MSi 2 N 2 O 2 

J. Mater. Chem. 15, 4492 (2005). 


MSi 2 N 2 O 2 :Ce 3+ 

J. Luminescence. 121, 441 (2006). 

SrSi 2 N 2 O 2 :Yb 3+ 








The Goals of the Research on MSi 2N2O2 Chem. Mater. 17, 3242 (2005) 

MSi 2N2O2:Ce :Ce 

J. Mater. Chem. 15, 4492 (2005). 

MSi 2N2O2:Eu :Eu 

Yb 

MSi 2N2O2 Eu 

Dy 

Eu 


Ce 

Eu 

Mn 

High QE







Experimental for MSi 2N 2O 2 

SrCO 3 

SrCO 

Si Si3N4 Ln Ln-O 

(Ln = Eu, Eu, 

Ce, Ce, 

Dy, Dy, 

Yb..) Yb..) 

SrSi 2N 

2N2O 2O2:Ln :Ln 

2 :Ln 

phosphor 

grinding 

Sintering at 1400 ~ 1600°C 

in 5~25%H 2 /N 2 


Abosrbance 







SrSi 2N2O2:Eu :Eu & SrSi 2N2O2:Ce :Ce 

Diffuse Reflectance Spectra 

Ce 

Eu 

300 400 500 600 700 

Wavelength (nm) 

Results and Discussion 

Sr 0.96 Si 2 N 2 O 2 :Eu 0.04 

Sr 0.96 Si 2 N 2 O 2 :Ce 0.04 

4.0x10 4 

4f 6 5d 1 


Energy [cm -1 ] 

3.5x10 4 

3.0x10 4 

2.5x10 4 

2.0x10 4 

1.5x10 4 

1.0x10 4 

0.5x10 4 

0.0 

[Xe] 

5d 1 

Ce 3+ 

4f 1 

H H: Host (MSi (MSi2N 2N2O 2O2) 2) 

A: Activator (Eu2+ A: A Activator (Eu ) 2+ A 

) 

S Sensitizer (Ce 3+ ) 

Engrgy 

transfer 

2 F7/2 

2 F5/2 

H 

H 

H 

H 

Engrgy transfer 

S 

H 

A 

H 

Eu 2+ 

4f 7 

A 

A 

H 

A 

8 S7/2 

H 

H 

H 

H

Relative intensity 







Sr 1-x-ySi 

Sr 

Emission Emission 

Si2N2O2:Eu :EuxCe 350 400 450 500 550 600 650 700 750 


Sr 1-x-y Si 2 N 2 O 2 :Eu x Ce y 

x = 0.04, y = 0 

x = 0, y = 0.04 

Ce y 


44% 

400 450 500 550 600 650 700 


Sr 1-x-y Si 2 N 2 O 2 :Eu x Ce y 

x = 0.04, y = 0 

x = 0.04, y = 0.01 

x = 0.04, y = 0.04 

x = 0.04, y = 0.08 

x = 0, y = 0.04 








Sr 0.96-ySi 0.96 

Emission Emission 

Si 2 N 2 O 2:Eu 


400000 

300000 

200000 

100000 

0 

:Eu0.04Dy 0.04Dyy 

y = 0 

y = 0.04 

y = 0.08 

y = 0.16 

y = 0.20 

48% 

450 500 550 600 650 700 


0.00 0.05 0.10 0.15 0.20 


Relative intensuty 

440000 

420000 

400000 

380000 

360000 

340000 

320000 

300000 

280000 

Dy Concentration 

Eu Dy







Sr 0.96-xSi 0.96 

Si2N2O2:Eu :Eux (Mn 

Intensity 

5.5x10 5 

5.0x10 5 

4.5x10 5 

4.0x10 5 

3.5x10 5 

3.0x10 5 

2.5x10 5 

2.0x10 5 

1.5x10 5 

1.0x10 5 

5.0x10 4 

Mn0.04 0.04 ) 

68% 

0.035 0.040 0.045 0.050 

Eu Concentration 

Mn 


Eu 

Doped without Mn 

Doped with Mn







Relative Intensity 

Eu Ce 

Eu Dy 

Eu 

Mn 

SrSi 2N2O2:Eu :Eu 

SrSi 2N2O2:Eu, :Eu,Ce Ce 

SrSi 2N2O2:Eu, :Eu,Dy Dy 

SrSi 2N2O2:Eu, :Eu,Mn Mn 

100% 

144% 

148% 

168% 









SrSi 2N2O2 :Yb Yb 

5d(t 2 )4f 13 ( 2 F 5/2 ) 

5d(e)4f 13 ( 2 F 5/2 ) 

5d(t 2 )4f 13 ( 2 F 5/2 ) 

5d(e)4f 13 ( 2 F 7/2 ) 

5d(t 2 )4f 13 ( 2 F 7/2 ) 

Sr 0.96 Si 2 N 2 O 2 :Yb 0.04 

250 300 350 400 450 500 


5d(t 2 )4f 13 ( 2 F 7/2 ) 

Yb 2+ : 4f 14 →4f 13 5d 1 

Energy [cm -1 ] 

40x10 4 

35x10 4 

30x10 4 

25x10 4 

20x10 4 

15x10 4 

10x10 4 


0.0 

Yb 3+ 

5d 

2 F7/2 

5x10 4 10,000cm -1 

[Xe] 4f13 


2 F5/2 

Sr 0.96 Si 2 N 2 O 2 :Yb 0.04 

450 500 550 600 650 700 750 


5d→4f







SrSi 2 N 2 O 2 :Eu,Mn 

Summary on (Oxy)nitrides 

( Oxy)nitrides 

SrSi 2 N 2 O 2 :Yb 


y 

0.9 

0.8 

0.7 

0.6 

0.5 

0.4 

0.3 

0.2 

0.1 

0.0 







510nm 

500nm 

490 nm 

520nm 

475 nm 

470 nm 

460 nm 

450 nm 

(a) 

Item 

CIE 1931 Chromaticity Diagram 

Green: 

SrGa 

540 nm 

2S4 :Eu 

Red: 

550 nm 

(CaSr)S:Eu 

530 nm 

60 mA 

5 mA 

60 mA 

(b) 

5 mA 

560 nm 

(d) 

570 nm 

60 mA 

5 mA 

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 

x 

(c) 

580 nm 

590 nm 

Green: 

SrSi 2 O 2 N 2 :Eu 

Red: 

CaSiN 2 :Ce 

600 nm 

Chromaticity coordinate 

x-diff. 

0.0625 

0.0022 

y-diff. 

0.0299 

0.0011 

Tc (K) diff. 

Highly stable threeband 

white light from an 

InGaN-based blue LED 

chip precoated with 

(oxy)nitride green/red 

Phosphors 


4144 

91 

Ra diff. 

Yang et al., Appl. Phys. Lett. 90, 123503 (2007) 

4.6 

1.9







Phosphate Phosphors 

KSrPO 4 








Nephelauxetic effect 

Charge density on the surrounding anions (type of network former) 

oxides > aluminates > silicates > borates > phosphates 

O 2- AlO 6 9- SiO 4 4- BO 3 3- PO 4 3- 

E 

5d 

free ion 

Eu 2+ 

4f 

Δ NE 

Δ NE (PO 4 3- ) < ΔNE (AlO 6 9- ) 

(higher covalency) 

Nephelauxetic 

Effect 

PO 3- unstable? 

4 








KSrPO 4: Eu 2+ 

Orthorhombic 

Pnma (space group) 

a = 7.35 Å 

b = 5.56 Å 

c = 9.642 Å 








Experimental for K(Sr 1-x Eu x )PO 4 

KH KH2PO SrCO SrCO3 Eu Eu2O3 PO 4 

K(Sr 1-xEu Eu 

1-xEux)PO )PO 

x )PO4 4 

phosphors 

grinding 

Sintering at: 

1. 500 ~ 600°C; 3 h; in air 

2. 1200 ~ 1400°C; 3h; 

in 5~25%H 2 /N 2 








K(Sr 1-xEu x)PO 4 

Normalized intensity (arb. unit) 

x = 0.010 

x = 0.007 

x = 0.005 

x = 0.003 

x = 0.001 

33-1045 KSrPO 4 

20 30 40 50 60 

2θ (degree) 


x = 0 

XRD








Intensity (cps) 

4x10 8 

5x10 8 4f - 5d transition of Eu 

x = 0.001 

x = 0.003 

x = 0.005 

x = 0.007 

x = 0.010 

2+ ions 

3x10 8 

2x10 8 

1x10 8 

λ em = 424 nm 

0 

300 320 340 360 380 400 


PL 










1.0x10 6 

8.0x10 5 

6.0x10 5 

4.0x10 5 

2.0x10 5 

0.0 

5d - 4f emission of Eu 2+ ions 

x = 0.001 

x = 0.003 

x = 0.005 

x = 0.007 

x = 0.010 

λ ex = 360 nm 

0.6 

0.000 0.002 0.004 0.006 0.008 0.010 

Eu 2+ Content (x) 

400 425 450 475 500 525 550 



0.9 

0.6 

0.3 

(0.161, 0.0238) 

y 

0.0 


1.0 

0.9 

0.8 

0.7 

White 

(0.31, 0.32) 

KSr 0.995 PO 4 :Eu 0.005 

0.0 0.3 0.6 

x 

PL








Intensity of 424nm emission (a.u) 

3000 

2500 

2000 

1500 

1000 

500 

0 

x = 0.005 

494 ns 

Relative decay time 

1.00 

0.96 

0.92 

0.88 

0.000 0.002 0.004 0.006 0.008 0.010 

Eu 2+ Content (x) 

0 1000 2000 3000 4000 5000 

Time (ns) 

I = I exp − 

( t / τ ) 

Decay time 


0







K(Sr 0.95Eu 0.05)PO 4 

Relative PL intensity 

100% 

80% 

60% 

40% 

20% 

0% 

KSr 0.95 PO 4 :Eu 0.005 

YAG:Ce 

0.5% Eu 


400 420 440 460 480 500 


50 100 150 200 250 300 


1.0x10 7 

8.0x10 6 

6.0x10 6 

4.0x10 6 

2.0x10 6 

0.0 

Temperature ( o C) 

Thermal stability 

30 o C 

50 o C 

100 o C 

150 o C 

200 o C 

250 o C 

300 o C







Summary on KSrPO4: Eu2+ 50 100 150 200 250 300 


Relative PL intensity 

100% 

80% 

60% 

40% 

20% 

0% 

KSr 0.95 PO 4 :Eu 0.005 

YAG:Ce 

0.5% Eu 


1.0x10 7 

8.0x10 6 

6.0x10 6 

4.0x10 6 

2.0x10 6 

30 o C 

50 o C 

100 o C 

150 o C 

200 o C 

250 o C 

300 o C 

0.0 

400 420 440 460 480 500 


Temperature ( o C) 

Tang et al., Appl. Phys. Lett. 90, 151108 (2007).







Published books 

5/22/2007 New Ceramic Phosphors for LEDs 31/78







Thanks Thanks for for your your attention! 

attention!

新陶瓷螢光材料於白光發光二極體製作之應用

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