Controlling the Crystallization Kinetics of Lead‐Free Tin Halide Perovskites for High Performance Green Photovoltaics

Abstract Tin halide perovskites are promising candidates for lead‐free perovskite solar cells (PSCs) not only due to their low‐toxicity, but also due to their ideal energy bandgap, high charge carrier mobility, and long hot carrier lifetime. The certified efficiency of tin halide PSCs has now reached over 10%, but this is still far from the theoretical expectation. Much of the efficiency gap relates to the poor quality of tin halide perovskite films due to the lack of in‐depth understanding about the crystal nucleation and growth mechanisms for such films. This recognition motivates the present review, which is focused on the crystallization kinetics of tin halide perovskites. In particular, starting from a germane discussion on crystal nucleation and growth theories, several methods that have been used for controlling the rapid crystallization of tin halide perovskites are dissected. Finally, the current challenges and prospects for tin halide PSCs are presented. This comprehensive review summarizes and illuminates the parameter space for the optimization of tin halide perovskite film quality, promoting the future development of ecofriendly PSCs with high efficiency and high stability.