Co-deposition of TiO2/CdS films electrode for photo-electrochemical cells

A densely packed TiO2 thin film onto an indium doped–tin oxide (ITO) substrate was synthesized at room temperature by chemical deposition and a CdS thin film was deposited onto the pre-deposited TiO2 film by a doctor blade route (powder of CdS was obtained from chemical deposition). TiO2/CdS film was annealed at 300 °C for 1 h in air for crystallinity improvement. The first grown TiO2 film was nanocrystalline, whereas the CdS film was polycrystalline as evidenced by X-ray diffraction (XRD) and selected area electron diffraction (SAED). Scanning electron microscopy (SEM) images show formation of mono-dispersed CdS spherical grains onto compact, densely packed spherical nanocrystalline grains of TiO2. The TiO2/CdS bilayer film was used in a photo-electrochemical cell as a working electrode, and a platinum electrode as a counter electrode (0.1 M lithium iodide electrolyte) under 80 mW/cm2 light illumination intensity.