Excimer formation and evolution of excited state properties in discrete dimeric stacking of an anthracene derivative: a computational investigation
Excimer formation and evolution of excited state properties in discrete dimeric stacking of an anthracene derivative: a computational investigation
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蒽衍生物离散二聚体堆积中准分子的形成和激发态特性的演化：计算研究
DOI：
10.1039/c8cp00834e
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发表时间：
2018-05-07
影响因子：
3.3
通讯作者：
Yang, Bing
中科院分区：
文献类型：
--
作者：
Gao, Yu;Liu, Haichao;Yang, Bing
在此，密度泛函理论（DFT）计算进行研究的离散二聚体的单取代的蒽衍生物（2-TA-AN），它表现出高效的纯激基缔合物荧光在其晶体形式。作为一个更实用的模型，系统地计算了它的几何构型、势能曲线和激发态性质，以更好地理解准分子的形成过程和电子物理性质。压缩的受激准分子几何形状负责高效的受激准分子发射，这是由于增强的刚性大大抑制了其非辐射振动。沿着三个方向的势能曲线揭示了激基缔合物形成沿着蒽长轴的非唯一性，这与实验结果吻合较好。在减少位移时，单体间电荷转移（CT）组件逐渐增加到一个近似相等的杂交与局部发射（LE）状态的单体在形成的激基缔合物。激基缔合物发射波长与单体间CT含量的关系显示出沿着三个方向的相似趋势，揭示了与激基缔合物的激发态性质从单体的LE到HLCT的本质转变有关的转折点。本研究结果将有助于更好地理解激基缔合物形成和光物理性质的结构-性质关系。
Herein, density functional theory (DFT) computations were performed to investigate the discrete dimer of a mono-substituted anthracene derivative (2-TA-AN), which exhibited highly efficient pure excimer fluorescence in its crystal form. As a more practical model, its geometry, potential energy curve and excited state property were systematically calculated to better understand the excimer formation process and photophysical properties. The compressed excimer geometry is responsible for the highly efficient excimer emission, arising from the enhanced rigidity that greatly suppresses its non-radiative vibrations. Potential energy curves along three directions reveal the non-uniqueness of excimer formation along the long axis of anthracene, which is in a good agreement with the experimental findings. Upon decreasing the displacement, the intermonomer charge-transfer (CT) component gradually increased towards an approximately equivalent hybridization with the locally-emissive (LE) state of the monomer during the formation of the excimer. The excimer emission wavelength versus intermonomer CT content shows a similar trend along the three directions, revealing a turning point related to the essential transition of the excited state properties from the LE of the monomer to the HLCT of the excimer. The present results will contribute to the better understanding of the structure-property relationships in excimer formation and photophysical properties.