Green anti-solvent modulation of the growth of binary FAXMA1-X tin-based perovskite and their photovoltaic properties

Abstract

Tin-based perovskite represents a highly promising alternative to lead-based perovskite, offering a number of significant advantages. These include non-toxicity, high absorbance, and excellent photovoltaic properties. The use of the toxic anti-solvent chlorobenzene (CBZ) in the preparation of tin-based perovskite thin films has the dual disadvantage of increasing the environmental hazards and the cost of subsequent treatment. The use of acetic acid (HAc) as a green anti-solvent has been demonstrated to effectively regulate the crystallization process of tin-based perovskite FASnI₃, resulting in the preparation of perovskite films of superior quality. To further enhance the performance of tin-based perovskite, Zhao et al., organic cation mixing was used to add MAI to the FASnI₃ system and optimize the ratio, resulting in an optimal ratio of FA (0.75) MA (0.25) (FA = NH₂CH = NH₂⁺, MA = CH₃NH₃⁺) (Zhao et al. Adv Sci 4(11):1700204, 2024). In this study, we choose the crystallization process during the preparation of binary FA_0.75MA_0.25SnI₃ perovskite using a green anti-solvent HAc. The findings demonstrated that HAc was capable of influencing the crystallization of binary tin-based perovskite, facilitating the formation of perovskite films with minimal pinholes and enhanced uniformity and crystallinity. Additionally, the resulting perovskite exhibits a band gap of 1.35 eV, which is in close alignment with the predicted ideal band gap as postulated by Schottky's theory. Furthermore, it displays enhanced hydrophobic properties. In the binary perovskite photovoltaic device prepared using the anti-solvent HAc, the maximum device efficiency reached 3.62%. The findings of this study will contribute to the understanding of the crystallization process of diverse perovskite materials in the presence of a green anti-solvent.

Graphical Abstract