CdSe Nanocrystal Assemblies on Anodized TiO2 Nanotubes: Optical, Surface, and Photoelectrochemical Properties

The in situ preparation of high-quality organically synthesized cadmium selenide (CdSe) nanocrystals on TiO 2 nanotubes (T_NT) prepared by anodization is presented. The deposition of CdSe nanocrystals has been facilitated under a high-pressure and low-viscosity solvothermal process. The formation, growth, and assembly of CdSe nanocrystals in the form of a dense film on T_NT have been studied using thermal (thermogravimetry and calorimetry) and optical (UV–vis and microscopy) techniques. It has been concluded that an organic treatment, followed by annealing under a nitrogen atmosphere at reduced temperatures, helps control CdSe nanocrystal morphology without causing significant particle size growth. Photoelectrochemical measurements indicate that the electrode assembly consisting of T_NT and CdSe can achieve a stable photocurrent density of 6.7 mA/cm 2 and a charge-separation efficiency of 35%.