Zhu Yuan-Ye, Xie Feng-Ming, Li Hao-Ze, Zhang Kai, Wang Han-Yang, Shi Hao-Nan, Zou Jianhua, Li Yan-Qing, Tang Jian-Xin
Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou, Jiangsu, 215123, P. R. China.
School of Physics and Electronic Science, East China Normal University, Shanghai, 200062, P. R. China.
Chem Asian J. 2024 Nov 4;19(21):e202400679. doi: 10.1002/asia.202400679. Epub 2024 Sep 12.
Despite the rapid development of thermally activated delayed fluorescent (TADF) materials, developing organic light-emitting diodes (OLEDs) with small efficiency roll-off remains a formidable challenge. Herein, we have designed a TADF molecule (mClSFO) based on the spiro fluorene skeleton. The highly twisted structure and multiple charge-transfer channels effectively suppress aggregation-caused quenching (ACQ) and endow mClSFO with excellent exciton dynamic properties to reduce efficiency roll-off. Fast radiative rate (k) and rapid reverse intersystem crossing (RISC) rate (k) of 1.6×10 s and 1.07×10 s, respectively, are obtained in mClSFO. As a result, OLEDs based on mClSFO obtain impressive maximum external quantum efficiency (EQE) exceeding 20 % across a wide doping concentration range of 10-60 wt %. 30 wt % doped OLED exhibits an EQE of 23.1 % with a small efficiency roll-off, maintaining an EQE of 18.6 % at 1000 cd m. The small efficiency roll-off and low concentration dependence observed in the TADF emitter underscore its significant potential.
尽管热激活延迟荧光（TADF）材料发展迅速，但开发效率滚降小的有机发光二极管（OLED）仍然是一项艰巨的挑战。在此，我们基于螺芴骨架设计了一种TADF分子（mClSFO）。高度扭曲的结构和多个电荷转移通道有效地抑制了聚集诱导猝灭（ACQ），并赋予mClSFO优异的激子动力学性质以降低效率滚降。在mClSFO中分别获得了1.6×10 s的快速辐射速率（k）和1.07×10 s的快速反向系间窜越（RISC）速率（k）。结果，基于mClSFO的OLED在10 - 60 wt %的宽掺杂浓度范围内获得了超过20 %的令人印象深刻的最大外量子效率（EQE）。30 wt %掺杂的OLED表现出23.1 %的EQE，效率滚降小，在1000 cd m时保持18.6 %的EQE。TADF发射体中观察到的小效率滚降和低浓度依赖性突出了其巨大的潜力。
