Solar conversion efficiency of dye-sensitized solar cells was improved by UV-O(3) treatment of TiO(2) before and/or after sintering. The enhancement was resulted from the removal of the residual organics originated from the TiO(2) precursor pastes, increased adsorption of dyes to the TiO(2), surface, and longer diffusion length and shorter electron transit time of electrons through the TiO(2) Mesoscopic structure. The power conversion efficiency of the cells reaches to 7.2% with the open circuit voltage of 0.71 V, the short circuit current density of 15.2 mA/cm(2) and the fill factor of 0.67 under illumination with AM 1.5 (100 mW/cm(2)) simulated sunlight. (C) 2008 Elsevier B.V. All rights reserved.