Non-interlayer and color stable WOLEDs with mixed host and incorporating a new orange phosphorescent iridium complex |
| |
Authors: | Li-Yuan Guo Xun-Lu ZhangMin-Jie Zhuo Chen LiuWang-Yang Chen Bao-Xiu MiYong-Hua Li Zhi-Qiang Gao |
| |
Affiliation: | Key Laboratory for Organic Electronics & Information Displays (KLOEID), Institute of Advanced Materials (IAM), Nanjing University of Posts & Telecommunications, Nanjing 210023, China; Jiangsu Engineering Centre for Plate Displays & Solid State Lighting, Institute of Advanced Materials (IAM), Nanjing University of Posts & Telecommunications, Nanjing 210023, China; School of Material Science and Engineering, Nanjing University of Posts & Telecommunications, Nanjing 210023, China |
| |
Abstract: | In this work, we have synthesized a new phosphorescent iridium complex (Bppya)2Ir(acac), as an orange dopant for organic light-emitting diodes (OLEDs). The device achieved an external quantum efficiency (EQE) of 22.4%, a current efficiency of 49.5 cd A−1 and a power efficiency of 38.9 lm W−1, which are among the highest values for orange OLEDs. Furthermore, color stable and high efficiency phosphorescent white OLED (WOLED) was demonstrated by utilizing a mixed-host in the emissive layers (EMLs) composed of a blue phosphor and the new orange phosphorescent emitter, as well as by avoiding the use of interlayers that commonly exist between different EMLs in WOLEDs. Our WOLED presented decent white emission with maximum efficiencies of 25.3 cd A−1 and 12.6%. Furthermore, the 1931 Commission Internationale de l’Eclairage color coordinates exhibited extremely small variation of (0.3940 ± 0.0102, 0.4323 ± 0.0046) in a wide luminance range from 49 to 38,035 cd m−2 when driving voltages increased from 4 V to 12 V. The root cause for this excellent color stability is the utilization of the mixed-host to obtain bipolar transport properties in EMLs as well as the eliminating of interlayer between different EMLs, which, on one hand, effectively broaden the exciton recombination zone; on the other hand, reduce the accumulation of triplet excitons at the emissive interface. |
| |
Keywords: | WOLED Color stability Mixed host Orange Iridium |
本文献已被 ScienceDirect 等数据库收录! |
|