Guo Shaoting, Liu Wen, Wu Yuling, Sun Jing, Li Jie, Jiang Hongyu, Zhang Mengfan, Wang Senhao, Liu Zuyuan, Wang Long, Wang Hua, Fu Hongbing, Yao Jiannian
Key Laboratory of Interface Science and Engineering in Advanced Materials, Ministry of Education, Taiyuan University of Technology, Taiyuan 030024, China.
Key Laboratory of Interface Science and Engineering in Advanced Materials, Ministry of Education, College of Chemistry, Taiyuan University of Technology, Taiyuan 030024, China.
J Phys Chem Lett. 2022 Aug 18;13(32):7547-7552. doi: 10.1021/acs.jpclett.2c02342. Epub 2022 Aug 10.
Understanding the structure-property relationships in organic semiconductors is crucial for controlling their photophysical properties and developing new optoelectronic materials. Quadrupolar molecules, donor-acceptor-donor (DAD), have attracted extensive attention in various optoelectronic applications. However, the systematic studies on the differences on photophysical properties between DAD and simple donor-acceptor (DA) chromophores are rarely reported. Herein we present a comparative study on the excited state dynamics of DA and DAD fluorescence systems using theoretical calculation and transient absorption spectroscopy. Results show that DA and DAD molecules exhibit similar excited state dynamics, which are attributed to the distinctive excited-state symmetry breaking (ESSB) phenomenon observed in a DAD system. The strong photoluminescence (PL) and ultrafast charge separation (CS) from an ESSB-induced partial charge transfer (CT) state were clearly detected in different solvent environments. These results not only offer insight into the excited state dynamics of the DAD fluorescence system but also provide some basic guidelines for designing new optoelectronic materials.
了解有机半导体中的结构-性质关系对于控制其光物理性质和开发新型光电器件材料至关重要。四极分子，即供体-受体-供体（DAD），在各种光电器件应用中引起了广泛关注。然而，关于DAD与简单供体-受体（DA）发色团之间光物理性质差异的系统研究鲜有报道。在此，我们利用理论计算和瞬态吸收光谱对DA和DAD荧光体系的激发态动力学进行了比较研究。结果表明，DA和DAD分子表现出相似的激发态动力学，这归因于在DAD体系中观察到的独特的激发态对称性破缺（ESSB）现象。在不同的溶剂环境中，均清晰地检测到了由ESSB诱导的部分电荷转移（CT）态产生的强光致发光（PL）和超快电荷分离（CS）。这些结果不仅有助于深入了解DAD荧光体系的激发态动力学，也为设计新型光电器件材料提供了一些基本指导。
