Improvement in performances of dye-sensitized solar cell with SiO2-coated TiO2 photoelectrode

The pure TiO2 and the nano-porous SiO2-coated TiO2 (STO) films were deposited on the FTO substrates by spray technique for the application of dye-sensitized solar cells (DSSCs). XRD pattern shows the pure TiO2 and STO films exhibits the same structure. We found that there is no much difference in dye absorption between the STO and the pure TiO2 films. The electrochemical impedance spectra reveal that insulating nature of the porous SiO2 increases surface resistance of the TiO2 film and supresses back transfer of the photogenerated electrons to the electrolyte. The field-emission scanning electron microscopy (FE-SEM) and energy dispersion X-ray spectroscopy (EDS) reveal that the surface morphology and the existence of SiO2 layer on the surface of the TiO2 films, respectively. The photoelectrochemical results show that the short-circuit photocurrent (J(SC)) increased from 16.73 mA cm(-2) to 18.31 mA cm(-2) and the open-circuit voltage (V(OC)) value changed from 0.71 V to 0.74 V for the STO films. The efficiency of cell has been greatly improved from 8.25 to 9.3%.