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利用密度泛函理论(DFT)和含时密度泛函理论(TD-DFT), 分别基于B3LYP和PBE1PBE方法研究了一系列含有不同给电子基团的吲哚染料分子(ID1-ID3)的电子结构和吸收光谱性质. 重点比较了不同电子给体对染料的分子结构、吸收光谱以及其在电池中的光伏性能的影响. 结果表明从ID1、ID2到ID3, 随着电子给体中苯环数目的增加, 吲哚分子上的共轭效应逐渐增大, 导致吲哚分子最高占据分子轨道-最低未占据分子轨道(HOMO-LUMO)之间的能隙变窄, 分子的吸收光谱发生红移. 染料分子的吸收光谱和 LUMO 能级分别影响染料的吸光效率和光电转化过程中电子的注入过程, 从而使其二者成为决定电池光伏性能的重要参数. 综合考虑上述两个参数对电池性能的贡献, 通过理论研究证实, 在ID1-ID3系列染料中, ID3具有较长的吸收谱带、较大的分子消光系数和合适的LUMO能级, 从而表现出最为优越的光伏性能, 这与实验得出的结论很好地吻合.
The electronic structures of a series of indole dye molecules (ID1-ID3) with different electron donating groups were studied based on the B3LYP and PBE1PBE methods using density functional theory (DFT) and time-dependent density functional theory (TD-DFT) And the absorption spectra of the dyes were investigated.The molecular structure, absorption spectra and the photovoltaic properties of the dyes in different batteries were compared.The results show that with the number of benzene rings in the electron donor from ID1, ID2 to ID3 , The conjugated effect on indole molecules gradually increases, leading to the narrowing of the energy gap between the highest occupied molecular orbital and the lowest unoccupied molecular orbital (HOMO-LUMO) of indole molecule and the red shift of the absorption spectrum of the molecule The absorption spectra of the molecules and the LUMO energy level affect the absorption efficiency of the dye and the electron injection process of the photoelectric conversion process, respectively, so that both of them become the important parameters that determine the photovoltaic performance of the battery. Considering the contribution of the above two parameters to the battery performance, Theoretical studies show that ID3 has the most excellent absorption band, larger molecular extinction coefficient and suitable LUMO energy level in ID1-ID3 series dyes Photovoltaic performance, which is in good agreement with the experimental conclusion.