The present invention relates to photoanodes, solar cells and methods and processes for producing the same. In some embodiments, the solar cells of the invention can do without a sintered nanoporous scaffold layer, making it possible to produce the solar cells in low-temperature procedures. In some embodiments, the invention encompasses organic-inorganic perovskite sensitizers, deposited on a smooth metal oxide layer. In some embodiments, the organic-inorganic perovskite sensitizers are deposited in a two-step sequential process.