Computational Nano-Materials Design of Low Cost and High Efficiency Cu2ZnSn[Se1-xSx]4 Photovoltaic Solar Cells by Self-Organized Two-Dimensional Spinodal Nanodecomposition

Abstract

We propose the possibility of spinodal nanodecomposition in Cu2ZnSn[Se1-xSx]4 (CZTSeS) for high efficiency photovoltaic solar cells, based on the first-principles calculations within the self-interaction-corrected local density approximation. By using the Korringa–Kohn–Rostoker coherent potential approximation method, electronic structures of CZTSeS are calculated. Due to the calculated positive mixing energy and type II band alignment between Cu2ZnSnSe4 and Cu2ZnSnS4, we can expect that the efficiency of CZTSeS becomes higher by spinodal nano-decomposition. Then we simulate the self-organized two-dimensional spinodal nanodecomposition by Monte Carlo method using the Ising model with chemical pair interactions calculated from the first principles.