A Revisit of Crystallization in Tin Halide Perovskite Thin Films: From Nucleation, Intermediate to Crystal Growth

Perovskite solar cells (PSCs) are exuding unique charm in the third generation of thin film solar cell technology with high power conversion efficiency (PCE) and low production cost. Recently, the lead-free tin halide perovskite solar cells (TPSCs) have drawn significant research interests due to the advantages of low toxicity, near-ideal bandgap and high carrier mobility. However, the rapid crystallization and easy oxidation limits the film quality and final performance of the solar cells. Therefore, the deposition of high-quality tin halide perovskite films is key to the advance of TPSCs. In this review, the classical theory of solution nucleation and crystal growth is reviewed and correlated to the practical deposition of tin perovskite film. The physicochemical properties of tin perovskite with those of lead counterpart and the differences in the crystallization process is carefully compared. On this basis, recent regulation strategies are systematically summarized in terms of the nucleation management, intermediate phase engineering and crystal growth regulation. In addition, the preparation of mixed tin-lead (Sn-Pb) PSCs toward high performance is also discussed, as well as the limiting factors for device performance and stability. Finally, the future challenges and prospects of the crystallization regulation are discussed toward more efficient and stable TPSCs. This review provided a comprehensive summary and discussion on the crystallization regulation of tin halide perovskite thin films. The classical theories of solution nucleation and crystal growth and correlated them to the actual deposition of perovskite thin films is reviewed. The influencing factors and difficulties in the crystallization process of tin perovskite, as well as advanced regulation strategies are then summarized. On this basis, the challenges to constructing more efficient and stable TPSCs in the future are discussed. image