Surface Modifications and Optoelectronic Characterization of TiO2‐Nanoparticles: Design of New Photo‐Electronic Materials

TiO₂ nanoparticles are of great current interest for applications in photo‐electronic materials including light‐energy conversion, artificial photosynthetic systems as well as photocatalysis. The success of these applications relies on the exciton recombination dynamics and visible‐light sensitivity of the TiO₂ nanomaterials. Thus, in order to develop the highly efficient photo‐electronic materials absorbing visible light, different low dimensional TiO₂ nanostructures such as nanodiscs, nanofibers and nanochains were synthesized, and thereafter their surfaces were modified by incorporating with Sn‐porphyrins and heteropoly acid. The optoelectronic properties of the surface‐modified nanomaterials were investigated with regard to the optical properties and the surface exciton dynamics by using both steady‐state and ultrafast time‐resolved laser spectroscopic techniques including single nanoparticle photoluminescence technique. These results were correlated with the photo‐electronic properties including photocatalytic activities and solar cell efficiencies, indicating that the electron transfer mechanism in the modified nanostructures may be similar to the “Z‐scheme” of the plant photosynthetic system so that both photocatalytic activity and solar cell efficiencies were synergistically enhanced by using two color illumination.