Key Laboratory of Green Chemistry and Technology of Ministry of Education, College of Chemistry, Sichuan University, 29 Wangjiang Road, Chengdu, 610064, P. R. China.
Angew Chem Int Ed Engl. 2023 Mar 13;62(12):e202218405. doi: 10.1002/anie.202218405. Epub 2023 Feb 14.
Suppressing aggregation-caused quenching (ACQ) effect and reducing device efficiency roll-off are both crucial yet challenging for multi-resonance (MR) emitters. Herein, we put forward a medium-ring strategy to design efficient MR emitters that feature heptagonal tribenzo[b,d,f]azepine (TBA) donors. The highly twisted conformation enlarges the intermolecular distances between the MR-emitting cores, and thus suppresses ACQ effect. Meanwhile, the introduction of heptagonal donors enhances spin-orbital coupling, so as to accelerate reverse intersystem crossing (RISC) process. This medium-ring strategy gives rise to the first example of blue MR emitter that simultaneously possesses radiative decay rate as fast as 10 s and RISC rate as fast as 10 s . Accordingly, DTBA-B2N3 enables to assemble high-performance blue organic light-emitting diodes (OLEDs) with maximum external quantum efficiency (EQE ) of 30.9 % and alleviated efficiency roll-off (EQE : 20.5 %).
抑制聚集导致的猝灭（ACQ）效应和降低器件效率滚降对于多共振（MR）发射器都是至关重要但具有挑战性的。在这里，我们提出了一种中环策略来设计高效的 MR 发射器，其特征是具有七元三苯并[b，d，f]氮杂卓（TBA）给体。高扭曲构象增大了 MR 发光核之间的分子间距离，从而抑制了 ACQ 效应。同时，引入七元供体增强了自旋轨道耦合，从而加速了反向系间窜越（RISC）过程。这种中环策略产生了首例同时具有辐射衰减率快至 10 s 和 RISC 率快至 10 s 的蓝色 MR 发射器。因此，DTBA-B2N3 能够组装具有最大外量子效率（EQE）为 30.9%和缓解效率滚降（EQE：20.5%）的高性能蓝色有机发光二极管（OLED）。
