Crystallization Dynamics of Sn-Based Perovskite Thin Films: Toward Efficient and Stable Photovoltaic Devices

Tin-based perovskites show great potential in photovoltaic applications, and the development of the corresponding solar cells (PSCs) has made exciting progress during the past few years. However, owing to the high Lewis acidity and easy oxidation of Sn²⁺, Sn-based perovskite films suffer from fast crystallization and easy formation of vacancy defects with low activation energy during the solution film-forming process, resulting in poor film quality and inferior device performance. Therefore, an in-depth understanding and rational control of film-forming dynamics of Sn-based perovskites is essential to improve the photovoltaic performance of their PSCs. In this review, the state-of-the-art developments in crystallization dynamics control for Sn-based perovskites and their impact on the photovoltaic performance of PSCs are systematically summarized. The review begins with the introduction of fundamentals and key difficulties for the control of the crystallization process of Sn-based perovskites. Then, the advanced strategies that focus on regulating the crystallization process of Sn-based perovskite films are comprehensively reviewed, including solvent engineering, additive engineering, cation engineering, and film-forming technique engineering. Finally, future perspectives and research directions, regarding the smart control of crystallization dynamics of Sn-based perovskite film, are discussed towards high-performance and stable Sn-based PSCs.