Review article on the lattice defect and interface loss mechanisms in kesterite materials and their impact on solar cell performance

Kesterite Cu2ZnSnS4 (CZTS), Cu2ZnSnSe4 (CZTSe), and its alloys Cu2ZnSn(Sx,Se1−x)4 (CZTSSe, 0 < x < 1), are cost-effective thin-film photovoltaic materials to meet future energy demands. The presence of more elements in these quaternary materials than binary or ternary materials provides flexibility in the fundamental physical and chemical properties. The huge Voc losses have limited the performance of devices. On the other hand, progressive studies for obtaining high efficiency kesterite-based Cu2ZnSnS4, Cu2ZnSnSe4, and Cu2ZnSn(Sx,Se1−x)4 devices have been ongoing over the past few years, but a concrete understanding is lacking. In this review, the lattice defect and loss mechanisms in kesterite materials and their impact on solar cell performance are analyzed systematically. The origin and the cause of atomic defects, deep disorders and interface properties, and their influence on the solar cell performance are discussed. In addition, a comprehensive correlation between the experimental and simulation methods has been attempted to determine the loss mechanisms in kesterite materials. This review also focuses on some approaches to overcome the loss mechanisms. These findings are expected to provide a path for better device performance.