Tailoring optical properties of TiO2 nanowires coated with Ag nanoparticles by plasmon coupling of Ag nanoparticles

TiO2 nanowires were grown on titanium foil by an alkali hydrothermal growth method. The as-synthesized nanowires are structurally uniform with diameters of 50–100 nm and lengths of up to a few micrometers. The as-prepared TiO2 nanowires were coated with Ag nanoparticles by reducing AgNO3 in solution. The experimental results indicate that the Ag nanoparticles can aggregate together on the surfaces of TiO2 nanowires by interconnection between nanoparticles. The degree of aggregation of Ag nanostructures can be controlled by changing the concentrations of Ag nanoparticles. The as-prepared nanostructures exhibit a wide optical absorption from 387 to 580 nm that can be easily tuned by controlling the degree of aggregation of Ag nanostructures. The results reveal that optical properties of the Ag-coated TiO2 nanowires can be enhanced by plasmon coupling of Ag nanoparticles. The as-prepared nanostructures may find potential applications in the field of solar cells.