有机发光二极管
材料科学
电致发光
光电子学
共发射极
兴奋剂
磷光
光致发光
单重态
量子效率
二极管
纳米技术
图层(电子)
荧光
光学
激发态
核物理学
物理
作者
Xiaomin Guo,Peisen Yuan,Xianfeng Qiao,Dezhi Yang,Yanfeng Dai,Qian Sun,Anjun Qin,Ben Zhong Tang,Dongge Ma
标识
DOI:10.1002/adfm.201908704
摘要
Abstract Aggregation‐induced emission (AIE) materials are highly attractive because of their excellent properties of high efficiency emission in nondoped organic light‐emitting diodes (OLEDs). Therefore, a deep understanding of the working mechanisms, further improving the electroluminescence (EL) efficiency of the resulting AIE‐based OLEDs, is necessary. Herein, the conversion process from higher energy triplet state (T 2 ) to the lowest singlet state (SS 1 ) is found in OLEDs based on a blue AIE material, 4′‐(4‐(diphenylamino)phenyl)‐5′‐phenyl‐[1,1′:2′,1′′‐terphenyl]‐4‐carbonitrile (TPB‐AC), obviously relating to the device efficiency, by magneto‐EL (MEL) measurements. A special line shape with rise at low field and reduction at high field is observed. The phenomenon is further clarified by theoretical calculations, temperature‐dependent MELs, and transient photoluminescence emission properties. On the basis of the T 2 ‐S 1 conversion process, the EL performances of the blue OLEDs based on TPB‐AC are further enhanced by introducing a phosphorescence doping emitter in the emitting layer, which effectively regulates the excitons on TPB‐AC molecules. The maximum external quantum efficiency (EQE) reaches 7.93% and the EQE keeps 7.57% at the luminance of 1000 cd m −2 . This work establishes a physical insight for designing high‐performance AIE materials and devices in the future.
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