Efficiency Enhancement of Cu₂ZnSn(S,Se)₄ Solar Cells via Alkali Metals Doping

Abstract

Doping of alkali metals in precursor solutions demonstrates an effective strategy to achieve high efficiency Cu2ZnSn(S,Se)4 solar cells. The properties of doped films are related to alkali metal radius. Smaller alkali atoms are beneficial for increasing carrier concentration, whereas larger atoms are conducive to grain growth. Over 8% efficiency of K-doped Cu2ZnSn(S,Se)4 solar cell with optimized CdS thickness is realized.