Optical properties of TiO₂@Ag nanowires and nanospheres

Abstract

Nanoparticles (NPs) with nonmetallic cores and metallic shells (such as Au, Ag, and Cu) can exhibit improve absorption efï¬ciency due to localized surface plasmon resonance (LSPR), charge density oscillations at the surfaces of these core-shell composite nanoparticles. In this study, the effect of the geometry of TiO₂@Ag core-shell composite nanoparticles on their optical absorption properties was theoretically illustrated in the wavelength ranges between the visible and infrared light regions of electromagnetic radiation. These nanostructures were modeled by varying the TiO₂ core and Ag shell radii of the composite nanospheres and nanowires. The results indicate that varying the TiO₂ core radius and Ag shell thickness can be used to tune the absorption efï¬ciency of these materials from the UV region to the visible or infrared regions of the electromagnetic spectrum. An increase in the absorption efï¬ciency with greater core radii was observed. The absorption efficiency peaks of core-shell nanospheres or nanowires increased with the shell radius. Theoretical modeling based on these results suggest that this nanomaterial can be effectively utilized so that its optical absorption properties can be tuned. These properties could help to synthesize TiO₂@Ag core-shell composite NPs for use in environmental applications such as treating contaminated water and in novel future devices.