Ordered Macroporous CdS-sensitized N-doped TiO2 Inverse Opals Films with Enhanced Photoelectrochemical Performance

The CdS sensitized N-TiO2 (CdS-N-TiO2) inverse opals films were prepared by a sol-gel method integrated with successive ionic layer adsorption and reaction (SILAR). In order to harvest the visible sunlight and enhance the photocurrent, photosensitization of CdS (narrow-bandgap semiconductor) and nitrogen doping are used to couple with TiO2 inverse opals. The good visible light absorption ability and significant increase of photoresponse of CdS-N-TiO2 inverse opals films have been observed compared to TiO2 or N-TiO2 inverse opals films. A promising photocurrent density of 0.83 mA/cm2 has been achieved for the CdS-N-TiO2 inverse opal as photoanode at 1.23 mV versus reversible hydrogen electrode (RHE) bias under simulated solar-light illumination. Because the synergistic effect of CdS sensitization and N-doping with periodically ordered inverse opal nanostructures, the photocurrent density is enhanced in comparison to the pristine TiO2 inverse opals films.