Mg掺杂Cu2ZnSnS4的第一性原理研究

First-principles Study on Mg Doping in Cu2ZnSnS4

采用基于密度泛函理论(DFT)的第一性原理对光伏材料Cu2ZnSnS4(CZTS)掺Mg进行了研究。通过建立Mg取代CZTS中Cu、Zn和Sn的点缺陷结构,计算Mg掺杂缺陷的生成能及对CZTS电子结构的影响。计算结果表明掺Mg不引入深能级缺陷也不改变材料的禁带宽度;并且富Sn条件更有利于Mg取代Cu形成施主缺陷,使p型转变为n型。本研究可为CZTS太阳能电池掺Mg的应用研究提供理论基础。

To date,solar cells with efficiency of 12.6%has been demonstrated via a hydrazine-based solution approach.Despite this progress,performance of Cu2ZnSn(S,Se)4 solar cells remains far lower than the Shockely-Quiser theoretical limit.We performed density functional theory calculations with hybrid functional approach to investigate the Mg-related defects in the kesterite structure of the Cu2ZnSnS4(CZTS)solar cell material.The substitution energies of Mg atom in CZTS were calculated in consideration of the atomic chemical potentials of the constituent elements of Cu,Zn,Sn,and the doping atom of Mg.From our calculation results,Mg doping in CZTS under certain Sn-rich growth condition is expected to convert the conduction from p-type to n-type.The present study provides a theoretical basis for exploring practical applications of Mg doping in CZTS solar cells.