Wang Yaxin, Tian Yiran, Gao Yixuan, Guo Zilong, Xue Zheng, Han Yandong, Yang Wensheng, Ma Xiaonan
Institute of Molecular Plus, Tianjin University, Tianjin 300072, P. R. China.
Engineering Research Center for Nanomaterials, Henan University, Kaifeng 475004, P. R. China.
J Phys Chem Lett. 2023 Nov 2;14(43):9665-9676. doi: 10.1021/acs.jpclett.3c02245. Epub 2023 Oct 23.
The emerging nitrogen-embedded multiple resonance (MR) emitters with an indolo[3,2,1-] carbazole (ICz) unit have exhibited promising performance for high-resolution organic light-emitting diode (OLED) devices, while the underlying photophysics has been rarely reported. In this work, the optical spectra, color purity, and emitting efficiency of ICz-based MR emitters were investigated by using electronic structure and thermal vibration correlation function (TVCF) calculations. Unlike B-N MR emitters, the high color purity of investigated ICz-based MR emitters was mainly contributed by considerable structural rigidity, which also greatly affects the radiative decay rate and fluorescence quantum yield of the S state. For the majority of investigated emitters, potential reverse intersystem crossing (RISC) channels (T → S and T → S) are limited by thermally inaccessible Δ* or insufficient spin-orbital coupling (SOC), which can be distinguished by the calculated temperature-dependent RISC rate pattern. We provided a systematic photophysical picture for ICz-based MR emitters that might be interesting for the OLED design and application community.
具有吲哚并[3,2,1-]咔唑（ICz）单元的新型氮嵌入多重共振（MR）发光体在高分辨率有机发光二极管（OLED）器件中表现出了良好的性能，但其潜在的光物理性质鲜有报道。在这项工作中，通过使用电子结构和热振动相关函数（TVCF）计算，研究了基于ICz的MR发光体的光谱、色纯度和发光效率。与B-N MR发光体不同，所研究的基于ICz的MR发光体的高色纯度主要归因于相当大的结构刚性，这也极大地影响了S态的辐射衰减率和荧光量子产率。对于大多数所研究的发光体，潜在的反向系间窜越（RISC）通道（T→S和T→S）受到热不可及的Δ*或自旋轨道耦合（SOC）不足的限制，这可以通过计算的温度依赖性RISC速率模式来区分。我们为基于ICz的MR发光体提供了一个系统的光物理图景，这可能对OLED设计和应用领域具有吸引力。
