상세정보
학술지
Non-linear Relation Between Emissive Dipole Orientation and Forward Luminous Efficiency of Top-emitting Organic Light-emitting Diodes
- 발행일
- 201811
- 출처
- Organic Electronics, v.62, pp.72-76
- ISSN
- 1566-1199
- 출판사
- Elsevier
- 협약과제
- 18PB2800, 수평분자 배열 극대화를 이용한 고효율/장수명 청색발광 소재‧소자 기술개발, 조현수
- 초록
- Studies related to emitting dipole orientation (EDO) have been widely carried out to obtain highly efficient organic light-emitting diodes (OLEDs) in a bottom-emitting structure. Herein, we report on the relation between EDO and the forward luminous efficiency of top-emitting OLEDs (TEOLEDs). The forward emission of OLED device is solely contributed by the horizontal dipole. However, the effect of horizontal and vertical dipole on the various optical modes in OLEDs structure is significantly different, resulting in changing the Purcell factor for the ratio of EDO. Therefore, as horizontally oriented dipole ratio (HODR) is increased, the efficiency is also increased but is not linearly increased. When Ir(ppy)2(acac) with predominantly horizontal EDO (74% HODR) was applied to top-emitting OLEDs, the device efficiency in the normal direction was improved by 26% compared with OLEDs based on Ir(ppy)3 with isotropic EDO (68% HODR), which is larger than the HODR difference between two dopants.
- KSP 제안 키워드
- Device efficiency, Dipole orientation, Linear relation, Luminous efficiency, Normal direction, Organic light-emitting diodes(OLEDS), Purcell factor, Top-emitting OLEDs, highly efficient, horizontal dipole, light-emitting diode(LED)