Preparation and photoelectric performance of ITO/TiO2/CdS composite thin films

ITO/TiO2/CdS composite thin films were successfully prepared by electrodeposition of CdS on ITO/TiO2 substrate. The prepared ITO/TiO2/CdS thin films were characterized in detail by X-ray diffraction, surface photovoltage, and scanning electronic microscopy techniques. The results indicated that the deposited CdS layer with about 1:1 stoichiometry of Cd and S distributes not only on the surface with cauliflower-like structure but also the TiO2 film interior and even in the immediate proximity to the surface of ITO substrate. The UV–vis absorption spectrum results suggested that the absorption peak of the ITO/TiO2/CdS film shifts from the ultraviolet region to the visible region in comparison to that of the ITO/TiO2 film. Furthermore, by the photocurrent–potential behavior and incident monochromatic photon to current conversion efficiency measurements, it can be also noted that the deposited ITO/TiO2/CdS thin films possess higher photoelectric conversion efficiency than the ITO/TiO2 films. The sensibilization of TiO2 with CdS can effectively improve steady photocurrent. Therefore, the modification of CdS for ITO/TiO2 can strongly ameliorate the photoelectric capability of ITO/TiO2 thin film, and the prepared ITO/TiO2/CdS thin films were expected to possess more excellent photoelectrochemical performance than the ITO/TiO2 films.