Fabrication and characterization of dye-sensitized solar cell based on ordered mesoporous TiO2 films

Dye-sensitized solar cells based on ordered mesoporous TiO2 films were fabricated by sol-gel technique. X-ray diffraction (XRD) analysis revealed that anatase phase was crystallized at 300 °C with initially crystallite size 3.2 nm and the crystallization was improved to 700 °C. Surface area analysis showed that the specific surface area of the films decreased from 163.43 to 87.15 m2/g and the pore size increased from 5.05 to 8.75 nm as the annealing temperature increased from 400 to 600 °C. The transmittance spectra that measured by UV/Vis spectrophotometer revealed that the transmittance maxima of the films decreased in the visible region and the absorption edges shifted to longer wavelengths. Photovoltaic measurements showed that the power conversion efficiency of the films initially enhanced to the maximum value of 3.61% with the increasing film thickness to 1.7 μm and then declined when the film thickness increased further.