Abstract: The PbS quantum dots(Q-PbS) were formed in situ on a nanocrystalline TiO₂ electrode by using chemical bath deposition techniques and the PMeT were prepared with electrochemical method on TiO₂/Q-PbS film. The photoelectrochemical properties of TiO₂/Q-PbS film and poly(3-methylthiophere)(PMeT) modified Q-PbS anchored nanostructured TiO₂ film were studied by using the photocurrent action spectra and the photocurrent dependence of potential. The bandgap of Q-PbS films was 1.68 eV. The energy level of Q-PbS film was determined with photoelectrochemical method. The results indicate that PMeT and Q-PbS respectively modified TiO₂ film and PMeT modified Q-PbS anchored nanostructured TiO₂ film produced photocurrent in the longer wavelength region under a certain condition. In infrared light region, the conversion efficiency of light to electricity for the composite semiconductor nanoporous films was greatly improved comparing with that of the nanostructured TiO₂.The experiment result shows that the p-n heterojuction existed in the nanostructure TiO₂/Q-PbS/PMeT film electrode, which resulted in the separation of electron/hole pairs generated by photoexcitation, thus photoelectric conversion performance was improved.

Key words: PbS quantum dots, Poly(3-methylthiophene), Photoelectrochemistry