A Comprehensive Review on the Recent Strategy of Cation Substitution in CZTS(Se) Thin Films to Achieve Highly Efficient Kesterite Solar Cells

Abstract

Kesterite Cu2ZnSnS4 (CZTS) and selenized CZTS (CZTSSe) are the most potential replacement of Cu(InxGa1‐x)Se2 (CIGS) as absorber layer in thin film solar cells, aligning with modern green energy policies. In spite of a reported power conversion efficiency (η) of nearly 14.9%, their efficiency still lags much behind their predecessors like cadmium telluride (CdTe) and CIGS. Major obstacles hindering the performance of CZTS based thin film solar cells pertain the formation of CuZn and ZnCu antisite defects, along with high density of 2CuZn+SnZn donor defects, which adversely affect open circuit voltage (VOC) and η. To combat these challenges, researchers have explored cation substitution by incorporating alternative isovalent atoms, such as substituting Ag/Li for Cu, Mn/Cd for Zn, and Ge/Ti for Sn, as a potent strategy to inhibit severe potential fluctuations and undesirable tail states caused by Cu‐Zn disorder and Sn related defects. Recently single cation substitution in CZTS (or CZTSSe) has garnered considerable attentions, while dual‐cation incorporation has emerged as an intriguing avenue to enhance device performance, although in its nascent stage of research and development. This review discusses recent progress on cation substitution to supress antisite defects in CZTS (or CZTSSe), leading to high efficiency thin film solar cell.This article is protected by copyright. All rights reserved.