Influences of alcoholic solvents on spray pyrolysis deposition of TiO2 blocking layer films for solid-state dye-sensitized solar cells

Abstract Influences of alcoholic solvents for titanium diisopropoxide bis(acetylacetonate) (TPA) precursor solutions on the spray pyrolysis deposited TiO 2 films and the photovoltaic performance of the solid-state dye-sensitized solar cells (SDSCs) using these TiO 2 films as the blocking layers were investigated. Smooth TiO 2 films were obtained by spray pyrolysis deposition of a TPA solution in isopropanol (IPA) at a relatively low temperature of 260 °C. On the other hand, when ethanol was used as solvent, the TiO 2 films fabricated at the same temperature showed much rougher surfaces with many pinholes. Our results showed that ethanol reacts with TPA to form titanium diethoxide bis(acetylacetonate) (TEA), which requires a higher thermal decomposition temperature than that of TPA. SDSCs with TiO 2 blocking layer films fabricated using a TPA solution in IPA showed higher power conversion efficiencies with smaller variations.