Abstract
Photovoltaic properties of wet-type dye-sensitized solar cells were investigated with emphasis on the structures of two types of TiO2-ZnO composites as photoelectrodes. One was the mixed electrode of TiO2 and ZnO powders. Another was the TiO2-coated ZnO nanorod array prepared by a sol-gel process. The composite films were loaded on a transparent electrode and clacined at 450-500°C, on which dye molecules were adsorbed. The current-voltage characteristics were measured in iodide electrolyte solution under a simulated solar light. The mixed electrode exhibited a significant decrease in current density and photovoltaic efficiency compared to TiO2 electrode. Although the photovoltaic efficiency of ZnO was lower than that of TiO2, TiO2 coating of ZnO nanorod array improved the photovoltaic properties. The addition of triblockcopolymer as pore former in TiO2 coating was effective to increase the photovoltaic efficiency. The control of the concentration of TiO2 slurry was also important for homogeneous penetration into ZnO nanorod array.
