Fig. 1: Targeted elimination strategy for Sn4+ defects.

a Schematic diagram of the preparation of Sn-based perovskite film based on precursor engineering. b Schematic diagram of SnX4 hydrolysis induced by moisture post-treatment in CsSnI3 film.
a Schematic diagram of the preparation of Sn-based perovskite film based on precursor engineering. b Schematic diagram of SnX4 hydrolysis induced by moisture post-treatment in CsSnI3 film.