Abstract
An innovative sequential eco-friendly spray coating (SEF-SC) technique is developed to uniformly deposit metal halide perovskite films on macroscale textured surfaces, such as textured crystalline-silicon wafers. Contrasting with previous work on spray-coated perovskite solar cells, the method presented in this work completely avoids the use of toxic and dangerous solvents. Both MAPbI(3) and CsFAMAPbI(3-)(x)Br(x) perovskite films deposited by SEF-SC show excellent optoelectronic properties and no phase segregation, even when synthesized in ambient conditions. Uniform perovskite coatings are obtained on textured-silicon heterojunction solar cells underlining the promise of this method, which holds the potential for scalable wet processing of perovskites on rough substrates, such as for low-cost perovskite/silicon tandem solar cell fabrication.