Photoelectrochemical Properties of CdS/CdSe Sensitized TiO2 Nanocable Arrays

Vertically aligned TiO2/CdS and TiO2/CdS/CdSe nanocable arrays on fluorine-doped tin oxide (FTO) were fabricated by electrochemical deposition of CdS and CdS/CdSe shells over TiO2 nanorod arrays. The morphology, composition, structure and optical absorbance of CdS and CdS/CdSe shells sensitized TiO2 nanorod arrays were characterized by different analytical methods. The CdS shell with a hexagonal structure and the CdSe shell with a face-centered structure were densely and uniformly coated on the tetragonal TiO2 nanorod cores both radially and longitudinally. The photovoltaic measurement showed that the photocurrent density obtained under AM1.5G illumination with a zero bias potential (Ag/AgCl electrode) largely increased from 2.17 to 6.57 mA/cm2, when the TiO2/CdS nanocables were further covered by the CdSe shell.