title: Influences of Conjugation Extent on the Aggregation-Induced Emission Quantum Efficiency in Silole Derivatives: A Computational Study.
abstract: The photophysical properties of a series of silole derivatives, with hydrogen (TPS), bromine (BrTPS), and conjugated phenyl (HPS), triphenylsilyethynyl (BTPES), and dimethylfluorene (BFTPS) substituents at 2,5-positions in both gas and aggregate phases have been investigated computationally by employing the correlation function rate formalism coupled with a hybrid quantum/molecular mechanics (QM/MM) approach. It is found that the solid-state fluorescence quantum efficiency first increases sharply with the degree of π-conjugation of the 2,5-substituents, then levels off, and finally starts to decrease slightly. This is because the side-group conjugation tends to enhance the radiative decay rate in both gas and solid phases. However, a further increase in conjugation leads to saturation in the radiative decay rate but increases the non-raditiave decay rate due to the decreased energy gap.
authors.affiliation: Key Laboratory of Organic Solids, Beijing National Laboratory for Molecular Science (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.|Department of Chemistry, Wuhan University, Wuhan, 430072, China.
authors.forename: Yujun
authors.initials: Y
authors.lastname: Xie
authors.affiliation: Key Laboratory of Organic OptoElectronics and Molecular Engineering, Department of Chemistry, Tsinghua University, Beijing, 100084, China.
authors.forename: Tian
authors.initials: T
authors.lastname: Zhang
authors.affiliation: Department of Chemistry, Wuhan University, Wuhan, 430072, China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Li
authors.affiliation: Key Laboratory of Organic Solids, Beijing National Laboratory for Molecular Science (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China. qpeng@iccas.ac.cn.
authors.forename: Qian
authors.initials: Q
authors.lastname: Peng
authors.affiliation: Key Laboratory of Organic Solids, Beijing National Laboratory for Molecular Science (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.
authors.forename: Yuanping
authors.initials: Y
authors.lastname: Yi
authors.affiliation: Key Laboratory of Organic OptoElectronics and Molecular Engineering, Department of Chemistry, Tsinghua University, Beijing, 100084, China. zgshuai@tsinghua.edu.cn.
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Shuai
keywords: QM/MM calculation; aggregation-induced emission; excited state radiative and non-radiative decay rate constants; fluorescence quantum efficiency; photophysics; siloles