TiO2 films prepared by micro-plasma oxidation method for dye-sensitized solar cell

Nanocrystalline TiO₂ films are widely investigated as the electrodes of dye-sensitized solar cell(s) with different preparation methods. In this paper, thin titanium dioxide films have been prepared on titanium plates by the micro-plasma oxidation method in the sulfuric acid solution. The thin TiO₂ films were sensitized with a cis-RuL₂(SCN)₂·2H₂O (L = cis-2,2′-bipyridine-4,4′-dicarboxylic acid) ruthenium complex and implemented into a dye-sensitized solar cell configuration. The influence of reaction current density (10, 15, 20, 25 and 30 A dm⁻²) on the structural and the surface morphology of the films was investigated by X-ray diffraction, scanning electron microscopy, atom force microscopy and X-ray photoelectricity spectroscopy. Impedance analysis for dye-sensitized solar cells was carried out by electrochemical impedance spectroscopy. The results show that the rise of current density leads to the increase in the amount of rutile and the thickness of the TiO₂ film, which makes the TiO₂ films have different photovoltages and photocurrents. The relatively higher photoelectricity properties were obtained in the TiO₂ films prepared at a current density of 20 A dm⁻². The open-circuit voltage and the short-circuit current are 605 mV and 165 μA cm⁻², respectively.