Lead-free systems, perovskites, perovskite crystallization, perovskite solar cells, tin oxidation Keywords: lead-free systems; perovskites; perovskite crystallization; perovskite solar cells; tin oxidation EN lead-free systems perovskites perovskite crystallization perovskite solar cells tin oxidation 1 1 1 02/28/22 20220224 NES 220224 Current protocols for solution-processed tin halide perovskite thin films rely on the use of DMSO.