Abstract: Compositions of matter and devices using those compositions are provided, which can, e.g., impede or restrict the migration of halides from a halide perovskite active layer. The composite material may include n layers of semiconductors, wherein n ? 2. Each layer of semiconductors may contain (i) one or more organic semiconductor layers and one or more inorganic semiconductor layer in contact with the one or more organic semiconductor layers, (ii) one or more composite semiconductor layers, each composite semiconductor layer containing an organic material and inorganic material, or (iii) a combination thereof.