Origins and Suppression of Sn(II)/Sn(IV) Oxidation in Tin Halide Perovskite Solar Cells

Abstract

Abstract Tin halide perovskite solar cells (TPSCs) have attracted aggressive research interest in the emerging perovskite photovoltaic devices due to their eco‐friendliness as compared to their lead halide counterparts. However, the easy Sn(II)/Sn(IV) oxidation of tin perovskites is a serious impediment to the development of TPSCs. Therefore, a clear understanding of the mechanisms, origins, and effects of the oxidation is essential to further boost the performance and stability of TPSCs. Herein, a systematic overview of the physicochemical process for the Sn(II)/Sn(IV) oxidation in TPSCs from the starting precursors to the final devices is presented. In addition, the effects of oxidation on the performance of TPSCs are then reviewed from crystal structure, defect chemistry, and optoelectronic properties. More importantly, the key issues to suppress the Sn(II)/Sn(IV) oxidation are seriously discussed on the basis of the reported antioxidation strategies. Finally, the challenges and outlooks toward TPSCs with higher power conversion efficiency and stability are proposed.