系统间交叉
磷光
密度泛函理论
轨道能级差
激发态
荧光
发光
光化学
材料科学
化学
光电子学
分子
计算化学
单重态
原子物理学
物理
量子力学
有机化学
作者
Ziwen Li,Ling‐Ya Peng,Xiu‐Fang Song,Yuanjun Gao,Ganglong Cui
标识
DOI:10.1063/1674-0068/cjcp2201021
摘要
Three-coordinate Au(I) complexes with thermally activated delayed fluorescence (TADF) have recently gained experimental attention. However, its luminescence mechanism is elusive. Herein, we have employed density functional theory (DFT), time-dependent DFT (TD-DFT), and QM/MM methods to investigate the excited-state and emission properties of the Au(I) complex in both gas and crystal phases. In both environments, the S1 and T1 emitting states mainly involve HOMO and LUMO and show clear metal-ligand charge transfer and intraligand charge transfer characters. The good spatial separation of HOMO and LUMO minimizes the S1–T1 energy gap, which benefits the reverse intersystem crossing (rISC) from T1 to S1. At 300 K, the rISC rate is faster than the T1 phosphorescence emission, which enables the TADF emission. However, at 77 K, such a rISC process is blocked and TADF disappears; instead, only phosphorescence is recorded experimentally. Importantly, this work highlights the importance of environments in regulating luminescence properties and contributes to understanding the TADF emission of organometallic complexes.
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