Photovoltaic Performance of a Novel TiO2 Electrode Consisting of a Mesoporous TiO2 Layer and a Compact TiO2 Blocking Layer for Dye-Sensitized Solar Cells

A double-layered TiO2 photoelectrode consisting of a compact TiO2 film as an electrolyte-blocking layer and a mesoporous TiO2 as a dye-adsorbed layer was prepared using the sputtering and a doctor-blade methods. The compact TiO2 blocking layer was deposited onto a transparent conducting oxide (TCO) substrate by reactive sputtering. Then, anatase mesoporous TiO2 was synthesized by means of a surfactant assisted sol-gel process. Comparison of the photovoltaic performances of the obtained solar cells (DSSCs) disclosed that the cells with a sputtering layer had higher conversion efficiencies than those without such a layer. Solar cells containing double-layered TiO2 electrodes exhibited a higher efficiency (3.15%) relative to conventional cells composed of TiO2 nanoparticles (1.75%). This behavior may result from the fact that mesoporous TiO2-based double layer has a higher surface area (304 m2g - 1), thus leading to an increase in the amount of dye adsorbed, which in turn enhances the photocurrent. In addition, it is expected that the compact structure of the blocking layer manufactured using the sputtering process will prevent electron recombination at the TCO.