Electron specific oxide double layer contacts for highly efficient and uv stable perovskite device

The present invention relates to an optoelectronic device comprising an electron transport layer (ETL) and a light harvesting layer, wherein the light harvesting layer comprises a metal halide perovskite and is provided on the ETL being a multilayer structure comprising at least two layers of metal oxide, at least one layer of which comprising a crystalline mesoporous metal oxide and at least one layer of which comprising an amorphous metal oxide or metal oxide nanocrystals, and wherein the layer being in contact with the light harvesting layer comprises the amorphous metal oxide or the metal oxide nanocrystals and is provided on the layer comprising the crystalline mesoporous metal oxide.