文献类型：期刊文献

英文题名：Optimal Dihedral Angle in Twisted Donor-Acceptor Organic Emitters for Maximized Thermally Activated Delayed Fluorescence

作者：Shi, Yuhao[1,5];Ma, Huili[2,3];Sun, Zhiyu[4];Zhao, Weijun[4];Sun, Guangyan[5];Peng, Qian[1]

机构：[1]Univ Chinese Acad Sci, Sch Chem Sci, Beijing 100049, Peoples R China;[2]Nanjing Tech Univ NanjingTech, Key Lab Flexible Elect KLOFE, 30 South Puzhu Rd, Nanjing 211816, Peoples R China;[3]Nanjing Tech Univ NanjingTech, Inst Adv Mat IAM, 30 South Puzhu Rd, Nanjing 211816, Peoples R China;[4]East China Univ Sci & Technol, Feringa Nobel Prize Scientist Joint Res Ctr, Frontiers Sci Ctr Materiobol & Dynam Chem, Sch Chem & Mol Engn, Shanghai 200237, Peoples R China;[5]Yanbian Univ Yanji, Dept Chem, Coll Sci, Jilin 133002, Peoples R China

年份：2022

卷号：61

期号：51

外文期刊名：ANGEWANDTE CHEMIE-INTERNATIONAL EDITION

收录：;EI(收录号：20224913212731);WOS:【SCI-EXPANDED(收录号:WOS:000888879500001)】；

基金：This work is supported by the National Natural Science Foundation of China (21973099, 22105069 and 22273105), the Fundamental Research Funds for the Central Universities, Shanghai Pujiang Program (20PJ1402900), Shanghai Natural Science Foundation (21ZR1418400) and the Hefei National Laboratory for Physical Sciences at the Microscale (KF2020103).

语种：英文

外文关键词：Electron-Vibration Coupling; Molecular Descriptor; Spin-Orbit Coupling; Thermally Activated Delayed Fluorescence (TADF)

摘要：The twisted donor-acceptor (D-A) organic formwork with a large dihedral angle (theta(DA)) is usually adopted to narrow the singlet-triplet energy gap for obtaining excellent thermally activated delayed fluorescence (TADF) emitters. However, the dependence of overall TADF properties on theta(DA) has not been systematically investigated to this day. Taking new designed CzBP, CzBP-1M and CzBP-2M via introducing methyl as investigated models, it is found that (i) with increasing theta(DA), the charge transfer component in S-1 is larger than that in T-1 in varying degrees, leading to non-monotonic spin-orbit couplings; (ii) the electron-vibration couplings between S-1 and T-1 states become the largest when theta(DA) approaching 80 degrees, facilitating phonon-driven up-conversion; (iii) the overall TADF rate reaches a peak at theta(DA)approximate to 80 degrees. By this, the TADF on/off switching is realized via methyl moiety for regulating theta(DA) from theoretical prediction to experimental confirmation. Importantly, the theta(DA) near 80 degrees would be a good descriptor for screening excellent D-A type TADF emitters.