Visible-light-induced patterning of Au- and Ag-TiO_2 nanocomposite film surfaces on the basis of plasmon photoelectrochemistry

摘要

A novel technique for patterning based on visible light at Au-TiO_2 and Ag-TiO_2 nanocomposite film surfaces has been developed for the first time.TiO_2 films loaded with Au and Ag nanoparticles were modified with hydrophobic thiols to obtain hydrophobic surfaces.The surfaces were converted to hydrophilic by visible light irradiation.Hydrophobic/hydrophilic patterning was also possible by visible light irradiation through a photomask.The patterning was due to removal of the thiol based on plasmon photoelectrochemistry.Visible-light-induced plasmon resonance at the Au and Ag nanoparticles gives rise to charge separation and redox reactions.The thiol is removed from the Au-TiO_2 film probably by oxidative desorption,and from the Ag-TiO_2 film owing chiefly to oxidation of Ag nanoparticles to Ag~+.