Reactive thermal evaporated amorphous tin oxide fabricated at room temperature and application in perovskite solar cells

Abstract Tin oxide (SnO x ) as a functional layer, such as electron transport layer (ETL) or buffer layer, is widely used in perovskite solar cells (PSCs). However, SnO x prepared by spin coating is not suitable to be applied to the solar cells with large area or rough substrates. In this paper, SnO x thin films served as the ETL of PSCs were prepared using a simple reactive thermal evaporation (RTE) method, and a convenient ultraviolet ozone treatment (UV‐O 3 ) at room temperature was carried out to replace the common post‐annealing process. The SnO x ETL prepared by RTE is suitable for substrates with arbitrary morphology, and the performance of the PSCs can be improved significantly after the ultraviolet ozone treatment of the SnO x layer. A power conversion efficiency (PCE) up to 20.62% was achieved on the planar PSCs with the RTE SnO x serving as the ETL. Conformal coverage of the RTE SnO x thin film and the perovskite layer on a textured Si surface was achieved, which is helpful for making fully textured monolithic perovskite/silicon tandem solar cells in the future.