Theoretical study of substitution effects on molecular reorganization energy in organic semiconductors
Theoretical study of substitution effects on molecular reorganization energy in organic semiconductors
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DOI：
10.1063/1.3632105
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发表时间：
2011-09-14
影响因子：
4.4
通讯作者：
Bredas, Jean-Luc
中科院分区：
文献类型：
--
作者：
Geng, Hua;Niu, Yingli;Bredas, Jean-Luc
化学取代是增强有机半导体性能的强有力的分子设计工具，例如，改善溶解性、分子间堆积或薄膜质量。然而，在微观水平上，取代一般倾向于增加分子重组敌人，从而降低固有的电荷-载流子迁移率。通过密度泛函理论计算，阐明了降低化学取代时重组能的策略。这里给出了空穴传输材料的具体例子，包括吲哚咔唑和几种三芳胺衍生物。通过将总重组能分解到内部坐标空间，我们能够识别出对重组能贡献最大的分子链段。研究发现，当取代降低(增强)该链段中相关前线分子轨道的振幅时，总重组能降低(增加)。特别是，在适当的位置进行氯化可以显著降低重组能。其他几个取代基或多或少也起到了类似的作用。(C)2011年美国物理研究所。[DOI：10.1063/1.3632105]
Chemical substitutions are powerful molecular design tools to enhance the performance of organic semiconductors, for instance, to improve solubility, intermolecular stacking, or film quality. However, at the microscopic level, substitutions in general tend to increase the molecular reorganization enemy and thus decrease the intrinsic charge-carrier mobility. Through density functional theory calculations, we elucidate strategies that could be followed to reduce the reorganization energy upon chemical substitution. Specific examples are given here for hole-transport materials including indolocarbazoles and several triarylamine derivatives. Through decomposition of the total reorganization energy into the internal coordinate space, we are able to identify the molecular segment that provides the most important contributions to the reorganization energy. It is found that when substitution reduces (enhances) the amplitude of the relevant frontier molecular orbital in that segment, the total reorganization energy decreases (increases). In particular, chlorination at appropriate positions can significantly reduce the reorganization energy. Several other substituents are shown to play a similar role, to a greater or lesser extent. (C) 2011 American Institute of Physics. [doi:10.1063/1.3632105]