Stability studies of CdS sensitized TiO₂ nanotubes prepared using the SILAR method

Titania nanotubes sensitized with CdS nanoparticles of different sizes and amounts were prepared using the successive ionic layer (SILAR) deposition method. UV/visible spectra indicate a red shift in CdS absorption upon increasing the number of SILAR cycles this is due to an increase in amount and size of CdS particles on the surface of titania nanotube. The stability of CdS particle sensitized on the surface of titania nanotubes were monitored using X-ray photoelectron spectroscopy (XPS). The formation of CdSO₄ species on the surface of CdS particles was evident from the XPS analysis. Smaller CdS particles, formed using a lower number of SILAR cycles, are more prone to oxidation than the larger particles formed using a greater number of SILAR cycles. The photocatalytic activity and solar cell efficiency is found to be dependent on the number of SILAR cycles employed.