Efficient Tin Halide Perovskite Solar Cells with Extended Processing Window

Abstract

Tin halide perovskite solar cells (TPSCs) have emerged as the most promising lead-free analogs, attributed to their low toxicity, desirable band gap and high carrier mobility. However, the rapid crystallization process poses a limitation on the enhancement of device performance and many toxic solvents are still used in the preparation process. Based on our study of green precursor solvents with N,N-diethylformamide, a green antisolvent anisole (AS) was further employed in this study to modulate the crystallization process of tin halide perovskite. It has been revealed that AS can be paired with dimethyl sulfoxide (DMSO) through hydrogen bonding, which further enhances the solvent extraction and accelerates the nucleation of tin halide perovskite crystals. Furthermore, the interaction between solvent and antisolvent prolongs the growth time of tin halide perovskites, resulting in a more uniform crystallization rate, which is characterized by the in-situ photoluminescence spectroscopy. The processing time window of perovskite film is thus extended effectively. Moreover, the crystal orientation is improved and the high-dimensional extended defects are reduced, which further suppresses the carrier recombination and improves the carrier transport. Consequently, the target device exhibits a higher power conversion efficiency and better stability than the commonly used chlorobenzene device. Therefore, this work provides a viable path for the green fabrication of lead-free perovskite photovoltaics.