Huang Tianyu, Wang Qi, Xiao Shu, Zhang Dongdong, Zhang Yuewei, Yin Chen, Yang Dezhi, Ma Dongge, Wang Zhaohui, Duan Lian
Key Laboratory of Organic Optoelectronics & Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, China.
School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China.
Angew Chem Int Ed Engl. 2021 Oct 25;60(44):23771-23776. doi: 10.1002/anie.202109041. Epub 2021 Sep 21.
Thermally activated delayed fluorescence (TADF) materials with through-space charge transfers (CT) have attracted particularly interest recently. However, the slow reverse intersystem crossing (RISC) and radiative decay always limit their electroluminescence performances. Herein, TADF molecules with ortho-linked multiple donors-acceptor (ortho-D -A) motif are developed to create near-degenerate excited states for the reinforcement of spin-orbit coupling. The incorporation of both through-bond and through-space CT enlarges oscillator strength. The optimal ortho-D -A compound exhibits a photoluminescence quantum yield of ca. 100 %, a high RISC rate of 2.57×10 s and a high radiative decay rate of 1.00×10 s simultaneously. With this compound as the sensitizer, a TADF-sensitized-fluorescent organic light-emitting diode shows a maximum external quantum efficiency of 31.6 % with an ultrapure green Commission Internationale de L'Eclairage y coordinate value of 0.69.
具有空间电荷转移（CT）的热激活延迟荧光（TADF）材料最近引起了特别关注。然而，缓慢的反向系间窜越（RISC）和辐射衰变总是限制它们的电致发光性能。在此，开发了具有邻位连接的多个供体-受体（邻位-D -A） motif的TADF分子，以创建近简并激发态来增强自旋-轨道耦合。键间和空间CT的结合增大了振子强度。最佳的邻位-D -A化合物同时表现出约100 %的光致发光量子产率、2.57×10 s的高RISC速率和1.00×10 s的高辐射衰变速率。以该化合物作为敏化剂，一种TADF敏化荧光有机发光二极管显示出31.6 %的最大外量子效率，国际照明委员会超纯绿色y坐标值为0.69。
