| 학회 | 한국재료학회 |
| 학술대회 | 2020년 가을 (11/18 ~ 11/20, 휘닉스 제주 섭지코지) |
| 권호 | 26권 1호 |
| 발표분야 | G. 나노/박막 재료 분과 |
| 제목 | Out-coupling efficiency enhancement of OLEDs by using vacuum gap corrugated microcavity structure |
| 초록 | Organic light-emitting diodes (OLEDs) have been highlighted as next-generation displays because of their excellent color gamut, self-emitting characteristics, applicability to various form factors and low power consumption. However, low optical efficiency is considered as a main obstacle for broadening the commercial potential and the range of applications. Generally, the efficiency of OLEDs can be represented by the external quantum efficiency (ηEQE), which is multiplication of the internal quantum efficiency (ηIQE) and the light out-coupling efficiency (ηcoupling). While the IQE of OLEDs can be achieved 100% theoretically, owing to the development of emitting materials, the EQE is still limited to ~20% due to the waveguide mode, substrate mode, and surface plasmon mode. There have been various approaches to overcome this issue, such as high refractive index substrate, micro-lens array, low-index grid, scattering layer, and photonic crystal (PC) structure. In this study, we researched vacuum gap photonic crystal layer inserted in microcavity structure to accomplish high optical efficiency and degenerate viewing-angle dependency of typical microcavity OLEDs. Vacuum gap was inserted to maximize light path manipulation, thus effectively extract substrate mode to air mode. Especially, by using IZO not only as anode but also as planarizing layer of Ag corrugated mirror, current density stabilization and electrical shorting prevention can be realized. By using finite-difference time domain (FDTD) numerical calculation, vacuum gap inserted corrugated microcavity structure showed light enhancement factor of 2.2 compared to conventional cavity-only device, and also demonstrated broad emission in ±50° which successfully emphasizes suppression of viewing angle dependence. |
| 저자 | Seungwon Lee, Ha Hwang, Byeong-Kwon Ju |
| 소속 | Korea Univ. |
| 키워드 | <P>OLED; out-coupling; microcavity</P> |
