聚苯胺能带结构和激发能与导电性能的理论分析

用PM3和UPM3-BS方法分别优化了二聚到十聚苯胺掺杂前(全还原型、全氧化型)及其电荷掺杂体的几何结构,同时获得了其HOMO-LUMO能隙；用ZINDO//PM3和UZINDO//UPM3-BS方法分别计算了它们的S0→S1光谱激发能；分别结合周期性边界条件方法和齐聚物外推法,系统地计算了几种形态聚苯胺的能带结构和H...

Computational Study on Band Structures, Excitation Energies and Conductive Properties of Polyaniline

Semiempirical quantum chemical calculations with PM3 and UPM3-BS methods have been performed to optimize the geometries and obtain HOMO-LUMO energy gaps of aniline oligomers fromdimer to decamer in fully reduced, fully oxidized and charge-doped forms, respectively. Then their S0→S1 excitation energies are computed with ZINDO//PM3 and UZINDO//UPM3-BS methods, respectively. Band structures and HOCO-LUCO band gaps for various types of polyanilines have been calculated with PM3 combined with periodic boundary condition. The HOMO-LUMO energy gaps and excitation energies for various types of polyanilines are obtained by extrapolating the values of corresponding oligomers to those of infinite ones. The results showed that the calculated optical excitation energies for various types of polyanilines agree well with corresponding experimental values quantitatively, and give good interpretation for the experimental observation of the conversion of polyaniline from an insulator to a conductor via doping. Furthermore, polarons, as the carriers, are confirmed to contribute largely to the metallic conductivity of doped polyaniline.