Han Weiguo, Liu Junjie, Ran Chunhao, Huang Zhenmei, Gao Ge, You Jingsong, Bin Zhengyang
Key Laboratory of Green Chemistry, Technology of Ministry of Education, College of Chemistry, Sichuan University, 29 Wangjiang Road, Chengdu, 610064, People's Republic of China.
Angew Chem Int Ed Engl. 2023 Nov 27;62(48):e202312297. doi: 10.1002/anie.202312297. Epub 2023 Oct 23.
The endeavor to develop high-performance narrowband blue organic light-emitting diodes (OLEDs) with low efficiency roll-off represents an attractive challenge. Herein, we introduce a hetero-acceptor design strategy centered around the heptagonal diimide (BPI) building block to create an efficient thermally activated delayed fluorescence (TADF) sensitizer. The alignment of a twisted BPI unit and a planar diphenyltriazine (TRZ) fragment imparts remarkable exciton dynamic properties to 26tCz-TRZBPI, including a fast radiative decay rate (k ) of 1.0×10 s and a swift reverse intersystem crossing rate (k ) of 1.8×10 s , complemented by a slow non-radiative decay rate (k ) of 6.0×10 s . Consequently, 26tCz-TRZBPI facilitates the fabrication of high-performance narrowband pure-blue TADF-sensitized fluorescence OLEDs (TSF-OLEDs) with a maximum external quantum efficiency (EQE ) of 24.3 % and low efficiency roll-off even at a high brightness level of 10000 cd m (EQE : 16.8 %). This showcases a record-breaking external quantum efficiency at a high luminance level of 10000 cd m for narrowband blue TSF-OLEDs.
开发具有低效率滚降的高性能窄带蓝色有机发光二极管（OLED）是一项具有吸引力的挑战。在此，我们引入了一种以七元二酰亚胺（BPI）结构单元为核心的异质受体设计策略，以创建一种高效的热激活延迟荧光（TADF）敏化剂。扭曲的BPI单元和平面二苯基三嗪（TRZ）片段的排列赋予了26tCz-TRZBPI显著的激子动力学特性，包括快速的辐射衰减速率（k）为1.0×10 s和快速的反向系间窜越速率（k）为1.8×10 s，同时伴随着缓慢的非辐射衰减速率（k）为6.0×10 s。因此，26tCz-TRZBPI有助于制造高性能窄带纯蓝色TADF敏化荧光OLED（TSF-OLED），其最大外量子效率（EQE）为24.3%，即使在10000 cd m的高亮度水平下也具有低效率滚降（EQE：16.8%）。这展示了窄带蓝色TSF-OLED在10000 cd m的高亮度水平下创纪录的外量子效率。
