%0 Journal Article
%T First-Principles Investigation on Triazine Based Thermally Activated Delayed Fluorescence Emitters
%A Jian zhong Fan
%A Shuai Qiu
%A Li li Lin
%A Chuan kui Wang
%J Chinese Journal Of Chemical Physics
%@ 1003-7713
%V 29
%N 3
%D 2016
%P 291-296
%K First-principles;Thermally activated delayed fluorescence;Charge-transfer states
%X Three kinds of triazine based organic molecules designed for thermally activated delayed fluorescence (TADF) emitters are investigated by first-principles calculations. An optimal Hartree-Fork (HF) method is adopted for the calculation of energy gap between the first singlet state (S1) and the first triplet state (T1). The natural transition orbital, the electronhole (e-h) distribution and the e-h overlap diagram indicate that the S1 states for the three systems include both charge-transfer and some localized excitation component. Further quantitative analysis of the excitation property is performed by introducing the index Δ*r* and the integral of e-h overlap *S*. It is found that symmetric geometry is a necessary condition for TADF emitters, which can provide more delocalized transition orbitals and consequently a small S1-T1 energy gap. Artful inserting aromatic groups between donors and acceptors can significantly enhance the oscillator strength. Finally, the energy state structures calculated with the optimal HF method is presented, which can provide basis for the study of the dynamics of excited states.
%R 10.1063/1674-0068/29/cjcp1508181
%U http://cjcp.ustc.edu.cn/hxwlxb_en/ch/reader/view_abstract.aspx
%1 JIS Version 3.0.0