碳掺杂α-S_8的光学性质和弹性性质的第一性原理计算

采用第一性原理研究了C原子在光催化剂α-S8中掺杂后体系电子结构、能带结构、光学性质、弹性性质以及其各向异性的变化规律.结果表明C原子在α-S8中掺杂后新形成的C―S键键长变短、键的重叠布居数增加、电荷密度增加,表明新键的共价性变强.掺杂结构的带隙为2.64 eV,比纯α-S8的带隙小0.15 eV,表明掺杂后的结构导电性增强.掺杂结构的光吸收波长延长至650 nm左右,极大地提高了α-S8的光吸收效率.弹性性质计算表明C掺杂后α-S8的机械性能下降,但仍为脆性材料.各向异性的研究表明掺杂后的材料各向异性增强.

First-Principles Calculations of Optical and Elastic Properties of Carbon-Doped α-S8

In this study, we performed a first-principles investigation of the rules governing changes in the electronic structure, band structure, optical properties, elastic properties, and anisotropy of an α-S₈ photocatalyst after carbon doping. It was shown that the bond length decreased, and the bond overlap population and charge density increased, with the formation of new C―S bonds, after doping. This indicated that the new bonds had enhanced covalence. The energy band gap of the doped structure was 2.64 eV, which is 0.15 eV lower than that of pure α-S₈, showing that doping increased the conductivity of α-S₈. The optical absorption spectrum of the doped system was extended to 650 nm, showing that the light absorption efficiency of α-S₈ was greatly enhanced. Calculations of the elastic properties showed that the mechanical capacity of carbon-doped α-S₈ decreased, but it remained brittle. The doped material had higher anisotropy.