Abstract: A film comprising a crystalline halide perovskite composition having the following formula: AMX3??(1) wherein: A is an organic cation selected from the group consisting of methylammonium, tetramethylammonium, formamidinium, and guanidinium; M is at least one divalent metal; and X is independently selected from halide atoms; wherein the crystalline film of the halide perovskite composition possesses at least one of an average grain size of at least 30 microns, substantial crystal orientation evidenced in an ordering parameter of at least 0.6, and a level of crystallinity of at least 90%. Methods for producing films of these halide perovskite compositions using ionic liquids instead of volatile organic solvents are also described herein.

Abstract: A film comprising a crystalline halide perovskite composition having the following formula: AMX3 ??(1) wherein: A is an organic cation selected from the group consisting of methylammonium, tetramethylammonium, formamidinium, and guanidinium; M is at least one divalent metal; and X is independently selected from halide atoms; wherein the crystalline film of the halide perovskite composition possesses at least one of an average grain size of at least 30 microns, substantial crystal orientation evidenced in an ordering parameter of at least 0.6, and a level of crystallinity of at least 90%. Methods for producing films of these halide perovskite compositions using ionic liquids instead of volatile organic solvents are also described herein.