Low-temperature formation of efficient dye-sensitized electrodes employing nanoporous TiO2 spheres

300-nm-sized nanoporous TiO2 spheres (SPs), blended with 25-nm-sized nanoparticles, were successfully applied to low-temperature fabrication of TiO2 electrodes for dye-sensitized solar cell (DSC). The introduction of SPs increased the adsorbed amount dye molecules, induced the efficient transport of photo-injected electrons through TiO2 layer, and offered an extended light-scattering efficiency in the long wavelength region. Furthermore, the adhesion of TiO2 layer to the FTO substrate was considerably improved. As a result, the photovoltaic conversion efficiency (η) of DSC processed at 140 °C was enhanced from 4.4% to 6.3%.