상세정보
학술지
Bi-Directional Organic Light-Emitting Diodes with Nanoparticle-Enhanced Light Outcoupling
- 저자
- Hong-Wei Chang, 이종희, 고태욱, Simone Hofmann, Bjorn Lussem, 유승협, Chung-Chih Wu, Karl Leo, Malte C. Gather
- 발행일
- 201311
- 출처
- Laser & Photonics Reviews, v.7 no.6, pp.1079-1087
- ISSN
- 1863-8880
- 출판사
- WILEY-VCH Verlag GmbH & Co. KGaA
- 협약과제
- 13VB1900, 에너지 절감을 위한 7인치기준 2W급 환경적응 디스플레이 신모드 핵심 원천 기술 개발, 추혜용
- 초록
- An effective method is presented for enhancing the outcoupling efficiency of translucent/bi-directional organic light-emitting diodes (TL/BD-OLEDs) with a bottom indium tin oxide (ITO) anode and a top cathode comprised of a thin Ag layer covered with an organic capping layer. Upon insertion of a nanoparticle (NP)-based scattering layer (NPSL) between the substrate and the ITO anode, the TL/BD-OLEDs exhibit significantly enhanced external quantum efficiency (EQE) in both emission directions. Furthermore, the NPSL improves the color stability of the TL/BD-OLEDs over a wide range of viewing angles. Simulations based on geometrical and statistical optics are performed to elucidate the mechanism by which the efficiency is enhanced and to establish strategies for further optimization. Simulations performed on the scattering layers with varying NP volume percentage reveal that the bottom-side emission is governed by competition between waveguide-mode extraction and backward scattering by NPs in the film, while the top-side emission is largely dominated by the latter. Optimized bi-directional OLEDs achieve a 1.64-fold enhanced EQE compared to reference devices without NPSL. An effective method is presented for enhancing the outcoupling efficiency of translucent/bi-directional organic light-emitting diodes (TL/BD-OLEDs) with a bottom indium tin oxide (ITO) anode and a top cathode comprised of a thin Ag layer covered with an organic capping layer. Upon insertion of a nanoparticle (NP)-based scattering layer (NPSL) between the substrate and the ITO anode, the TL/BD-OLEDs exhibit significantly enhanced external quantum efficiency (EQE) in both emission directions. Furthermore, the NPSL improves the color stability of the TL/BD-OLEDs over a wide range of viewing angles. Simulations based on geometrical and statistical optics are performed to elucidate the mechanism by which the efficiency is enhanced and to establish strategies for further optimization. Simulations performed on the scattering layers with varying NP volume percentage reveal that the bottom-side emission is governed by competition between waveguide-mode extraction and backward scattering by NPs in the film, while the top-side emission is largely dominated by the latter. Optimized bi-directional OLEDs achieve a 1.64-fold enhanced EQE compared to reference devices without NPSL. © 2013 by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
- KSP 제안 키워드
- Ag layer, Backward scattering, Bi-directional, Capping layer, Co. KGaA, Color stability, External Quantum Efficiency, Light outcoupling, Organic capping, Organic light-emitting diodes(OLEDS), Scattering layer