목차 1. 형광체종류및특성 2. Light Emitting Diode Phosphor 2

형광체 (Phosphor) 2012. 6. 25 한밭대학교신소재공학과박인용 Phosphor 1

1. 형광체의종류및특성 1.1 형광체 (Phosphors) 란? 1.2 발광과정과형광체의구조 1.3 형광체의 Size 효과 1.4 형광체분말의합성법 1.5 형광체분말의용도 Phosphor 3

1.1 형광체 (Phosphors) 란? Energy Converter : 여러가지에너지를가시광선으로바꾸어주는 무기또는유기화합물 Luminescence Visible light Electron beam UV light X-ray Phosphor Host Lattice Activators Sensitizer Phosphor 4

에너지원에따른형광체의분류 1 Photoluminescence ( 광발광 ) : electromagnetic (often UV) radiation Florescent Lamp, PDP, LED 2 Cathodoluminescence ( 음극선발광 ) : energetic electrons CRT, FED 3 Electroluminescence ( 전계발광 ) : electric field ELD 4 Chemiluminescence : chemical reaction 5 Triboluminescence : mechanical energy Phosphor 5

1.2 발광과정과형광체의구조 Excitation ( 여기 ) S H A 발광 에너지전이 : relaxation ( 완화 ) A : Activator (luminescence center) H : Host (holding the activator ions) S : Sensitizer (increasing the luminescent efficiency) Phosphor 6

Ene ergy Step 1 Host Lattice Step 2 Step 3 Step 4 Activator Step 1 : Absorption 여기원으로부터에너지의흡수 Step 2 : Excitation 활성제중심내에서에너지준위의여기 Step 3 : Relaxation Excitaion r Emission Relaxation process s 여기상태의완화 Step 4 : Emission 기저상태로의천이에기인한광방출 r 0 Ground state Effective radius (r) Phosphor 7

형광체의구조 1 Activator ( 활성제, luminescence center) : - 실제로빛을내는이온. - 기저준위와여기준위사이의전이에의해에너지를흡수또는방출. - 방출에너지의형태는전자기파의방출 (radiation transition) 과열방출 (non-radiative transition) 2 Host ( 모체, holding the activator ions) : - activator 이온을잡아주는역할. - Host의영향매우큼. 효율이높은형광체개발은 host에의한에너지흡수와흡수된에너지가얼마나효율적으로 activator로이동 (energy transfer) 하느냐가중요 Phosphor 8

3 Sensitizer ( 증감제, increasing the luminescent efficiency) : - 자체는빛을흡수, 방출하지않으나, activator 의광효율을 증가시키는역할. ( 예 ) 모체의결정성증가, 모체의전도성향상으로 activator 로의 energy transfer 효율증가, activator 의 doping 효율 증가등의연구가진행중. Luminescence killer : - 주로이차상이나전이금속과같은불순물을지칭. - Host 또는 activator가흡수한에너지가전이되는사이에 luminescence killer에의해그에너지가흡수되어 phonon ( 음파 ) 의형태로방출. Phosphor 9

색좌표 CIE 1931 Chromaticity Diagram 자연의모든색은편자안의점들로표현된다. 색도표상에밝기는표시되지않는다. x y = = X X + Y + Z Y X + Y + Z Phosphor 10

CIE 1976 Chromaticity Diagram u' = - 2x 4x + 12y + 3 v' = - 2x 9y + 12y + 3 Phosphor 11

1.3 형광체의 Size 효과 Semiconductor : Exciton radius Exciton : 외부에너지에의하여형성된 e - 과 h + 쌍을이루고있는상태 Semiconductor 의경우 exciton 의지름에의존하여 quantum size effect를나타냄 보통 1 10nm 범위를가짐 Semiconductor의 quantum size effect를형성하기위해서는 1 10nm 크기를가진 nanoparticle이필요 Quantum Size Effect of Semiconductor Ex) CdSe Phosphor 12

Ionic Crystal Size 감소 : 정전기적에너지감소용해도증가평균결합길이증가 Insulator particles quantum size effect를나타내기보다는 surface chemistry에변화를줌 Optical Property Change Bulk phosphors by the chemical composition Quantum dot phosphors by changing the particle size by the chemical composition Phosphor 13

efficiency Lumin nescence Variation of Luminescence Efficiency ZnS nanophosphor Surface-related non-radiative recombination 100 10 1 0.1 NANO Increase of activator efficiency due to quantum confinement Decrease of efficiency due to surface recombination BULK Bulk efficiency 1 10 100 1000 10000 Phosphor particle size (nm) B. R. Chakraborty et al, Nanotechnology, 16, 1006 (2005). Phosphor 14

1.4 Synthesis of Phosphor Powders Solid State Process - Solid State Reaction - Mechanochemical Process Wet Chemistry - Sol-Gel Process - Hydrothemal Synthesis - Solvothermal Synthesis - Precipitation (Homogeneous, Coprecipitation) Vaporization - Combustion Synthesis - Glycine Nitrate Process Phosphor 15

1.5 형광체분말의용도 각종디스플레이소자용형광체 CRT Phosphor Blue Green Red ZnS:Ag,Al ZnS:Cu,Al Y 2 O 2 S:Eu (Cathode Ray Tube) Lamp Phosphor Blue Green Red White (SrCaBaMg) 5 (PO 4 ) 3 Cl:Eu LaPO 4 :Ce,Tb Y 2 O 3 :Eu Ca 10 (PO 4 ) 6 FCl:Sb,Mn (Fluorescent Lamp) PDP Phosphor Blue Green BaMgAl 10 O 17 :Eu Zn 2 SiO 4 :Mn Red (Y,Gd)BO 3 :Eu (PDP) X-Ray Phosphor Blue CaWO 4 Green Gd 2 O 2 S:Tb UV (Y,Sr)TaO 4 :Nb (X-Ray Intensifying Screen) Phosphor 16

형광체의여기원 형광체종류 여기원 응용분야 Photo- UV (254 nm) Fluorescent Lamp luminescence VUV (147 nm) PDP Cathodoluminescence Electroluminescence High Voltage e-beam (25kV) Low Voltage e-beam (100V이하) (300-5000 V) High Voltage AC Field Low Voltage DC CRT VFD FED ELD LED Phosphor 17

PDP 용형광체의특성 CIE색좌표상대발광색형광체방사 X Y 효율 1/10 잔광시간 기호 Red (Y,Gd)BO 3 :Eu 3+ 0.64 Y 2 O 3 :Eu 3+ 0.65 0.35 0.35 1.8 1.0 9ms 3ms D E Green Zn 2+ 2 SiO 4 :Mn 0.24 0.71 1.0 14ms B BaAl 12 O 19 :Mn 2+ 0.18 0.73 1.1 17ms C Blue BaMgAl 14 O 23 :Eu 2+ 0.15 0.07 1.5 <1ms A Phosphor 18

d b a. (Y,Gd)BO 3 :EU (RED) b. Zn 2 SiO 4 :Mn (GREEN) c. BaAl 12 O 19 :Mn (GREEN) d. BaMgAl 14 O 23 :Eu(BLUE) a c RGB 형광체의 Quantum Efficiency (a) (Y,Gd)BO 3 :Eu 3+ (b) Zn 2 SiO 4 :Mn 2+ (c) BaAl 12 O 19 :Mn 2+ (d) BaMgAl 14 O 23 :Eu 2+ Phosphor 19

PDP 용형광체의발광스펙트럼 Phosphor 20

Nichia PDP Phosphor (http://www.nichia.com) NP # Composition S.G. NP- 107 NP- 200 NP- 203 NP- 205 NP- 340 NP- 360 NP- 361 Emission Peak (nm)/color Band Width (nm) BaMgAl 10 O 17 :Eu 3.83 450 Blue 53 Zn 2 SiO 4 :Mn 4.13 528 Green 42 YBO 3 :Tb 4.66 543 Green Line BaAl 12 O 19 :Mn 3.76 515 Green 35 Y 2 O 3 :Eu 5.05 611 Red Line (Y,Gd)BO 3 :Eu 5.04 592 Red Line YBO 3 :Eu 4.66 592 Red Line S.G. : Specific Gravity Phosphor 21

VFD 용형광체 [ 형광체의조성에따른발광개시전압및 Peak 파장 ] 발광색 형광체의조성 발광개시전압 V th [V] 발광 PEAK 파장 [nm] Green ZnO : Zn 3.5 505 Blue ZnS : Cl + In 2 O 3 6.5 465 Yellowish Green ZnS : Cu,Al + In 2 O 3 6.0 530 Greenish Yellow (Zn 0.50,Cd 0.50 )S : Ag,Al + In 2 O 3 4.5 565 Yellowish Orange (Zn 0.40,Cd 0.60 )S : Ag,Al + In 2 O 3 4.5 605 Orange (Zn 0.30,Cd 0.70 )S : Ag,Al + In 2 O 3 3.5 640 Reddish Orange (Zn 0.22,Cd 0.78 )S : Ag,Al + In 2 O 3 3.5 665 In 2 O 3 : 첨가제로써도전성물질. Phosphor 22

Intensity of Emission Re elative VFD 용형광체발광특성 100% 430 465 505 515 530 548 565570 605 640 665 Peak Wavelength (lp) 50 400 430 460 490 520 550 580 610 640 670 700 730 760 Wavelength (nm) Phosphor 23

2. Light Emitting Diode 2.1 White LED 구현방법 2.2 White LED 용형광체의합성및특성 2.3 LED 시장전망 Phosphor 24

LED 의발전역사 Phosphor 25

LED 성능발전 Phosphor 26

미래형 LED Phosphor 27

Energy Gap (ev) 2.1 White LED 구현방법 LED 재료 6.0 5.0 4.0 3.0 2.0 1.0 GaN AlN Al x Ga 1-x N 계 : < 364 nm GaN(cubic) Direct bandgap Indirect bandgap ZnS MgS MgSe SiC AlP ZnSe GaP InN AlAs GaAs In x Ga 1-x N 계 : >364 nm CdSe InP -UV Blue Green(525nm) Si Ge 3.0 4.0 5.0 6.0 Sapphire Lattice Constant (A ) Phosphor 28

백색 LED 를구현하기위한제작방법 LED-based and LED-plus-phosphor based approaches for white light sources implemented as di-, tri-, and tetrachromatic sources. E. F. Schubert and J. K. Kim, Science, 308, 1274-1278 (2005). Phosphor 29

White LED 구현방법 R,G,B-LED Color rendering index ( 연색지수 ) : 광원이얼 마나색채를태양광및완전복사체등과같은 기준광에가깝게재현하는지를평가하는계수 3개의 LED 사용각각의 LED 제어어려움 B-LED + Yellow Phosphor 상대적낮은발광효율, 낮은 CRI. 전류밀도에따라 CRI 변화 : 태양광에가까운백색광을얻기가어렵다. UV-LED + R,G,B Phosphors 고전류하에서사용가능높은효율, 높은 CRI, 색온도조절가능다른전류밀도에서도높은색채안정성색감우수 : 연구가장활발형광체조합의복잡성, 높은효율의적색형광체결여 Phosphor 30

Phosphor based white LEDs Phosphor 31

B-LED + Yellow Phosphor Phosphor 32

2.2 White LED 용형광체의합성및특성 Table. Comparison of synthesis methods in terms of the particle sizes, morphology control, required temperatures, cost and limitations. From MSE R, 71, 1-34 (2010). Phosphor 33

Table. Methods for preparation of YAG:Ce. From MSE R, 71, 1-34 (2010). Phosphor 34

EL spectra of the white LEDs using both InGaN-based blue-leds and (a) Y 3 Al 5 O 12 :Ce 3+, Pr 3+ phosphors with varying the amount of Pr 3+ and (b) yellow emitting (Y 1-x Tb x ) Y 3 Al 5 O 12 :Ce 3+ phosphors with varying the amount of Tb 3+. From J. Lumin. 126 (2007) 371. Phosphor 35

Table. Spectroscopic and structural properties of Ce 3+ -doped garnets. J.L. Wu, G. Gundiah, and A.K. Cheetham, Chem. Phys. Lett. 441 (2007) 250. Phosphor 36

SEM images of YAG:Ce prepared by (a) co-precipitation, (b) sol gel, (c) combustion, (d) solid-state synthesis. From Mater. Sci. Eng. B 106 (2004) 251. Phosphor 37

Emission spectra of 4 mol% Ce-doped YAG prepared by (a) combustion, (b) sol gel, (c) co-precipitation, (d) solid-state synthesis [120]. From Mater. Sci. Eng. B 106 (2004) 251. Phosphor 38

Table. Characteristic of some phosphors other than YAG:Ce for pc- WLEDs excited by blue-led chips (nitrides and oxynitrides are not included). Phosphor 39

EL spectra of white LEDs using (a) 460 nm chip and (b) 405 nm chip and (c) a yellow LED using 380 nm chip measured under a forward bias of 20 ma. From Appl. Phys. Lett. 90 (2007) 41906. Phosphor 40

Normalized PL and PLE spectra of Sr 3 SiO 5 :Ce 3+,Li +. From Appl. Phys. Lett. 90 (2007) 41906. Phosphor 41

Table. Summary of some single-phased white-emitting phosphors applicable for pc-wleds. Phosphor 42

황색광전환세라믹소재특허등록현황 회사특허광전환소재 Nichia US 5 998 925 (Jul 29, 1996) YAG:Ce OSRAM US 6 669 866 (Jul 23, 1999) TAG:Ce GE US 6 429 583 (Nov 30, 1998) Ba-orthosilicate OSRAM WO 02/11214 (Jul 28, 2000) (Sr,Ba)-orthosilicate Toyoda Gosei/LWB/Tridonic US 6 943 380 (Dec 28, 2000) US 6 809 347 (Dec 28, 2000) (Ca,Sr,Ba)-orthosilicate (Ca,Sr,Ba)-orthosilicate Phosphor Technology WO 04/111156 (May 17, 2003) (Ca,Sr,Ba)-orthosilicate Intermatix Corp. US 7 267 787 (Sep 11, 2007) M-orthosilicate(:Eu, halide) KRICT US 7 046 826 (May 16, 2006) KR 10 0670478 (Jan 10, 2007) Sr 3 SiO 5 :Eu (Sr,Ba,Mg)-orthosilicate 출처 : 백색 LED 용형광체기술분석, Mar. 2008 디스플레이뱅크 Phosphor 43

2.3 LED 시장전망 세계각국의 LED 조명지원현황 중국 호주 조명의 30% 를 LED 로대체해연간 580 억 KWh 절약하는 LED 프로젝트추진! 2010~2012년까지백열전구판매중지법안추진! 유럽 2012 년 8 월부터 LED 로차량용낮라이트의무화! 미국 2020 년까지조명의 50% 를 LED 로보급! 한국 2012 년까지 LED 조명비중을 30% 로향상! Phosphor 44

Evolution of luminous efficacy performance of white light sources. Commercially available high-power LED performance is indicated by the points along the solid blue curve. From J. Display Technol. 3 (2007) 160. Phosphor 45

Projected cost of light. Arrows show the present cost of ownership for incandescent and fluorescent lighting. From Proc. IEEE 93 (2005) 1691. Phosphor 46

LED 원가분석및핵심부재산업동향 그림. LED Package 의주요부재 그림. 3528 SMD 패키지의원가구조 http://www.displaybank.com/new2004/research/report_show.php?id=592 Phosphor 47

국내 LED 시장규모전망 LED 산업매년평균 45% 고성장예상 -2013년정부 13조투자 LED 시장전망 - LED성장성 è 2008 ~ 2011년사이성장 Peak Phosphor 48

전세계 LED LCD TV 시장규모전망 출처 : LED LCD TV 업체별로드맵및시장전망 2009 년 12 월, 디스플레이뱅크 Phosphor 49

신규성장산업 ( 지속성장 ) CCFL대비 LED특성환경적측면 CCFL LED 수은 (Hg) 사용친환경 ( 유해물질無 ) 수명 (hrs) 30,000 100,000 소비전력 (40'' 기준 ) 170W 100W 색체재현 최고 90% 100% 이상가능 BLU 용 LED 시장전망 (LED 단품기준 ) 2007 2008 2009 2010 3,194 6,735 12,760 22,605 (Stategies Unlimited 2006, 단위 : 억원 ) Phosphor 50

2009 년 LED LCD TV 브랜드별판매지역현황 http://www.displaybank.com/new2004/research/report_show.php?id=494 Phosphor 51

글로벌 LED 산업지원전망 LED 가로등 홍콩최대규모의 LED 옥외광고 Phosphor 52

농가보급형 LED 광처리장치 LED< 발광소자 > 조명받고인삼이 ' 무럭무럭 ' 조선일보사회, IT/ 과학 2009.01.22 ( 목 ) 오전 3:26 Phosphor 53

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