Characterizing the Conformational Distribution in an Amorphous Film of an Organic Emitter and Its Application in a 'Self‐Doping' Organic Light‐Emitting Diode

Autor: Cai-Jun Zheng, Xue Mei Ou, Chihaya Adachi, Chun-Sing Lee, Yi Ting Lee, Xiao Chun Fan, Shao Li Zhang, Gaole Dai, Jia Xiong Chen, Jia Yu, Jiansheng Jie, Xiaohong Zhang, Kai Wang, Yi-Zhong Shi, Shiyun Xiong, Yoichi Tsuchiya
Rok vydání: 2021
Předmět:
Zdroj: Angewandte Chemie International Edition. 60:25878-25883
ISSN: 1521-3773
1433-7851
Popis: The conformational distribution and mutual interconversion of thermally activated delayed fluorescence (TADF) emitters significantly affect the exciton utilization. However, their influence on the photophysics in amorphous film states is still not known due to the lack of a suitable quantitative analysis method. Herein, we used temperature-dependent time-resolved photoluminescence spectroscopy to quantitatively measure the relative populations of the conformations of a TADF emitter for the first time. We further propose a new concept of "self-doping" for realizing high-efficiency nondoped OLEDs. Interestingly, this "compositionally" pure film actually behaves as a film with a dopant (quasi-equatorial form) in a matrix (quasi-axial form). The concentration-induced quenching that may occur at high concentrations is thus expected to be effectively relieved. The "self-doping" OLED prepared with the newly developed TADF emitter TP2P-PXZ as a neat emitting layer realizes a high maximum external quantum efficiency of 25.4 % and neglectable efficiency roll-off.
Databáze: OpenAIRE
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