替代元素对光催化半导体Cu2ZnSnS4能带结构优化的第一性原理研究

First-principles Study on the Band Structure Optimization for the Photocatalyst Cu2ZnSnS4 through Element Substitution

关键词:  光催化半导体  Cu₂ZnSnS₄  掺杂  第一性原理计算

Key words:  photocatalyst  Cu₂ZnSnS₄  doping  first-principles calculations

摘要:

[目的]为了增加Cu₂ZnSnS₄价带顶和导带底与水的氧化还原势之间的能量差,使催化反应具有更多的驱动力。[方法]利用第一性原理计算,对Cu₂ZnSnS₄电子结构进行分析。[结果]Ag掺入Cu位能够降低其价带顶而不改变导带底位置,而Ge掺入Sn位能够提升其导带底而不改变价带顶位置。[结论]通过优化(Cu_1-xAg_x)₂Zn(Sn_1-yGe_y)S₄合金的配比,可使其达到光催化半导体最理想的能带结构。

Abstract:

[Objective] In order to supply more driving force for water splitting, we can increase the energy interval both between valence band maximum (VBM) and water oxidation level, and between conduction band minimum (CBM) and water reduction level by element doping.[Methods] Using the first-principles calculations, we have investigated the electronic structure of Cu₂ZnSnS₄.[Results] We found that Ag substitution for Cu can lower the energy position of VBM and do not change the energy position of CBM, while Ge substitution for Sn can raise the energy position of CBM and do not change the energy position of VBM.[Conclusion] We can get the optimal band structure for water splitting through changing the ratio in (Cu_1-xAg_x)₂Zn (Sn_1-yGe_y)S₄ alloy.