Enhanced charge collection and photocatalysis performance of CdS and PbS nanoclusters co-sensitized TiO2 porous film

Abstract

A novel translucent TiO2 porous film was prepared through etched method. The CdS, PbS and CdS/PbS nanoclusters were imbedded on TiO2 porous film by successive ionic layer adsorption and reaction method. Microstructure, morphology, optical and photoelectron-chemical properties of the as-synthesized thin films were investigated systematically. XRD and morphology analysis showed that PbS or CdS nanoclusters have been attached to the TiO2 porous films. It was found that the energy band gap of TiO2 porous film decreased from 3.46 to 3.2 eV after sensitized with nanoclusters. The photocurrent density of ITO/TiO2 photoelectrode increased from 0.017 to 0.28 mA/cm2 after co-sensitized with CdS and PbS nanoclusters. Besides, the photoelectrode sensitized with two sorts of nanoclusters showed evident higher photocurrent density than which sensitized just one sort of nanoclusters. The photocurrent density of ITO/TiO2/PbS and TO/TiO2/CdS photoelectrode was 0.11 mA/cm2 and 0.22 mA/cm2 respectively. 0.28 mA/cm2 can be obtained by ITO/TiO2/CdS/PbS photoelectrode. The results showed that the optical and photoelectrochemistry properties and phtotcatalysis performance of TiO2 porous film were greatly improved by co-sensitized with CdS and PbS nanoclusters.