Inuence of Electron Donating Ability on Reverse Intersystem Crossing Rate for One Kind of Thermally Activated Delayed Fluorescence Molecules  

供电子能力对一类热活化延迟荧光分子反系间窜越速率的影响（英文）

作　　者：Ming-lang Wang Jian-zhong Fan Li-li Lin 

机构地区：[1]Shandong Province Key Laboratory of Medical Physics and Image Processing Technology,School of Physics and Electronics,Shandong Normal University,Jinan 250014,China [2]Department of Electronics,Peking University,Beijing 100871,China

出　　处：《Chinese Journal of Chemical Physics》2018年第3期291-299,367,共10页化学物理学报（英文）

基　　金：This work was supported by the National Natural Science Foundation of China(No.11374195 and No.21403133),the Taishan Scholar Project of Shandong Province,the Promotive Research Fund for Excellent Young and Middle-aged Scientists of Shandong Province(No.BS2014CL001),and the General Financial Grant from the China Postdoctoral Science Foundation(No.2014M560571).

摘　　要：First-principles calculations are applied for investigating influence of electron donating ability of donor groups in eight thermally activated delayed fluorescence（TADF） molecules on their geometrical structures and transition properties as well as reverse intersystem crossing（RISC） processes. Results show that the diphenylamine substitution in the donor part can slightly change the bond angle but decrease bond length between donor and acceptor unit except for the lowest triplet state（Ti） of carbazole-xanthone molecule. As the electron donating ability of donor groups is increased, the overlap between the highest occupied molecular orbital（HOMO） and the lowest unoccupied molecular orbital（LUMO） is decreased. As the diphenylamine groups are added in donor part, the delocalization of HOMO is enlarged,which brings a decreased energy gap(△ES1-T1) between the lowest singlet excited state（S1）and T1 state. Furthermore, with the calculated spin-orbit coupling coefficient(HSO), one finds that the larger value of ■ is, the faster the RISC is. The results show that all investigated molecules are promising candidates as TADF molecules. Overall, a wise molecular design strategy for TADF molecules,in which a small △ES1-T1 can be achieved by enlarging the delocalization of frontier molecular orbitals with large separation between HOMO and LUMO, is proposed.

关 键 词：Thermally ACTIVATED DELAYED fluorescence Donating ABILITY REVERSE intersystem CROSSING SPIN-ORBIT coupling 

分 类 号：O64[理学—物理化学]