(color online) Scheme illustration of the intercalation reaction to form the perovskite film and schematic structure of the PSC. (a) First, the inorganic lead halide was sublimed, and then, the as-deposited inorganic seeding layer was reacted with organic molecules through a penetration process. (b) Schematic structure of the PSC with the perovskite film prepared by sequential vacuum deposition and evaporation–solution methods.