Round-comb FeO@SnO heterostructures enable efficient light harvesting and charge extraction for high-performance all-inorganic perovskite solar cells.

The precise design of an electron transport layer (ETL) to improve the light-harvesting and quality of perovskite (PVK) film plays a crucial role in the photovoltaic performance of n-i-p perovskite solar cells (PSCs). In this work, a novel three-dimensional (3D) round-comb FeO@SnO heterostructure composites with high conductivity and electron mobility induced by its Type-II band alignment and matched lattice spacing is prepared and employed as an efficient mesoporous ETL for all-inorganic CsPbBr PSCs. Arising from the multiple light scattering sites provided by the 3D round-comb structure, the diffuse reflectance of FeO@SnO composites is increased to improve the light absorption of the deposited PVK film.