Heterostructural Composites of TiO2 Mesh-TiO2 Nanoparticles Photosensitized with CdS: A New Flexible Photoanode for Solar Cells

A flexible electrorde utilizing TiO2 nanotubes (T_NT) anodically grown on titanium mesh with TiO2 nanoparticles as an overlying layer for solar cell applications has been investigated. Deposition of cadmium sulfide nanocrystals (CdS) for visible light absorption was carried out through successive ionic layer adsorption and reaction (SILAR) method. The addition of a TiO2 nanoparticle layer (T_NT/T_NP) prepared via TiCl4 exposure and subsequent heat treatment on TNT before CdS deposition was found to increase the deposition and utilization of CdS for the same number of SILAR cycles as compared to without TiO2 nanoparticles. The increased loading of CdS, at a result of T_NP deposition, enhanced visible light absorbance as well as the photoelectrochemical properties. Spectroscopic and photoelectrochemical studies indicate that the T_NP assisted improved dispersion of CdS results in at least 2-times higher photocurrent than did the T_NT/CdS system. Preliminary tests demonstrate the stable performance of the T_NT/T_NP/CdS photoanode in a prototype solar cell configuration,