Preparation and property study of CdS quantum dot sensitized nanocrystalline TiO₂ heterostructure films

Nanocrystalline TiO₂ solution was prepared by hydro-thermal treatment at 230°C with titanium(IV) isopropoxide (C₁₂H₂₈O₄Ti) as precursor solution. Anatase TiO₂ nanocrystalline films with hierarchical structure were prepared on FTO glass substrates by electrohydrodynamic (EHD) technique and sintered at 450°C. CdS quantum dot sensitized nanocrystalline TiO₂ heterostructure films were deposited by chemical bath method using the Cd(NO₃)₂ solution and Na₂S solution as the reactants. The crystal structure, morphology and optical property of the film were investigated. The results indicate that nanocrystalline TiO₂ films stack with the submicron spherical clusters, submicron and nanometer channels with wide dimension formed among the clusters which can facilitate the solution facilitation and ions adsorption. Nanocrystalline TiO₂ heterostructure films exist with CdS quantum dots with the range of 3-5nm. UV-vis absorbance spectra verified the blue shift of heterostructure films due to the quantum confinement effects of quantum dots.