Stepwise cosensitization is carried out on Al₂O₃-coated nanocrystalline TiO₂ layers using two organic dyes (JK-2 and SQ1) having complementary spectral absorption bands in the visible region. The Al₂O₃ coating results in the retardation of the interfacial charge recombination dynamics at the oxide/sensitizer interface and improves the overall performance of the dye-sensitized solar cells. CB = conduction band.