| Issue |
Korean Chemical Engineering Research,
Vol.49, No.3, 320-324, 2011
Vol.49, No.3, 320-324, 2011
CdSe 나노입자 형광층 구조에 따른 백색 LED 발광 특성 연구
Luminescence Properties of White LED with Different CdSe nanoparticles Phosphor Layer
TOPO/TOP로 안정화된 CdSe 반도체 발광 나노입자를 용해열 방법을 이용하여 합성하였다. 합성 온도 및 시간 조절을 통하여 540 nm 녹색 발광과 620 nm 적색발광 CdSe 나노입자를 얻었다. 형광체 변환 백색 발광다이오드(LED)는 460 nm 발광 InGaN 발광다이오드(LED) 여기원(excitation)과 540, 620 nm 발광 CdSe 나노입자 형광체를 결합하여 제작하였다. CdSe 나노입자 형광층은 녹색과 적색이 혼합된 단층과 분리된 다층구조로 이루어졌으며, 형광층 구성에 따른 백색 LED 소자의 특성 차이를 비교하였다. 단층구조 백색 LED는 20 mA에서 5.78 lm/W의 효율을 가지며, 형광층 내에서의 에너지 전이로 인하여 적색광이 강한(0.36, 0.45)의 색좌표를 보였다. 반면 다층 구조 백색광 LED는 20 mA에서 7.28 lm/W의 효율과 순수 백색광 영역인(0.32, 0.34)의 색좌표를 나타냈다. 또한, 400 nm의 청자색 LED를 여기원으로 적용 시, 소자의 효율이 8.76 lm/W로 증가하였다.
TOPO/TOP capped CdSe nanoparticles were synthesized via thermal-solvent method. The 540 nm green and 620 nm red emitting CdSe nanoparticles were obtained by controlling the reaction time and temperature. Phosphor conversion white LED was produced combining a 460 nm emitting InGaN LED chip as an excitation source with 540 and 620 nm CdSe nanoparticles as phosphors. The single or double phosphor layer was fabricated by mixing with epoxy, and investigated the effects on the luminous properties of the white LED. The single phosphor layer white LED showed 5.78 lm/W with CIE of (0.36, 0.45) in reddish white, and the double phosphor layer white LED showed 7.28 lm/W with that of (0.32, 0.34) in pure white at 20 mA. When the 400 nm near-UV LED was applied to optical pumping source, the luminous efficiency of white LED was enhanced to 8.76 lm/W.
[References]
- Shimizu Y, Sakano K, Noguchi Y, Moriguchi T, “Light Emitting DeviceHaving a Nitride Compound Semiconductor and a Phosphor Containing a Garnet Fluorescent Material" U.S. Patent 5998925, 1999
- Jang HS, Jeon DY, Appl. Phys. Lett., “Yellow-emitting Sr3SiO5:Ce3+, Li+ Phosphor for White-light-emitting Diodes and Yellow-light-emitting Diodes" 0419061-3, 90, 2007
- Lee SH, Koo HY, Ko DR, Lee SM, Kang YC, Korean Chem. Eng. Res., “Characteristics of BaMgAl10O17:Eu Phosphor Powders Prepared from Spray Solution with Organic Additives and NH4Cl Flux”, 48(1), 75, 2010
- Park JK, Choi KJ, Yeon JH, Lee SJ, Kim CH, Appl. Phys. Lett., “Embodiment of the Warm White-light-emitting Diodes by Using a Ba2+ Codoped Sr3SiO5:Eu Phosphor" 0435111-3, 88, 2006
- Heliotis G, Stavrinou PN, Bradley DC, Appl. Phys. Lett., “Spectral Conversion of InGaN Ultraviolet Microarray Light-emitting Diodes Using Fluorene-based Red-, Green-, Blue-, and White-light-emitting Polymer Overlayer Films" 103505-103508, 87, 2005
- Bowers MJ, McBride JR, Rosenthal SJ, J. Am. Chem. Soc., “White-Light Emission from Magic-Sized Cadmium Selenide Nanocrystals", 127(44), 15378, 2005
- Alivisatos AP, Science, “Semiconductor Clusters, Nanocrystals, and Quantum Dots", 271(5251), 933, 1996
- Peng XG, Manna L, Yang WD, Wickham J, Scher E, Kadavanich A, Alivisatos AP, Nature, “Shape Control of CdSe Nanocrystals", 404(6773), 59, 2000
- Chen H, Hsu C, Hong H, IEEE PHOTONIC TECH L., “InGaN.CdSe.ZnSe Quantum Dots White LEDs”, 18, 193, 2006
- Wang H, Lee K, Ryu J, Hong C, Cho Y, Nanotechnology., “White Light Emitting Diodes Realized by Using an Active Packaging Method with CdSe/ZnS Quantum Dots Dispersed in Photosensitive Epoxy Resins", 19, 145202, 2008
- Chung W, Park K, Yu HJ, Kim J, Chun B, Kim SH, Opt. Mater., “White Emission Using Mixtures of CdSe Quantum Dots and PMMA as a Phosphor", 32, 515, 2010
- Zlateva G, Zhelev Z, Bakalova R, Kanno I, Inorg. Chem., “Precise Size Control and Synchronized Synthesis of Six Colors of CdSe Quantum Dots in a Slow-Increasing Temperature Gradient", 46, 6212, 2006
- Fairchild MD, “The CIE Photopic Luminous Efficiency Function" Addison Wesley, Reading, MA, 1998
참고문헌정보(참고문헌, 인용문헌)는 화학공학소재연구정보센터에 의해 제공되고 있습니다.