Effects of TiO ₂ shells on optical and thermal properties of silver nanowires

A simple and efficient coating method of silver nanowires with uniform shells of TiO ₂ has been established using 2-mercaptoethanol monolayers. The thickness of the titania coating layer can be controlled by changing the concentration of the precursor solution. In situ TEM thermal annealing studies showed that the silver nanowire core remains intact until temperatures of 750 °C, which is significantly higher than the melting temperature of the bare silver nanowires. After this temperature, the Ag nanowires were melted and subsequently vaporized, leaving TiO ₂ nanotubes. The effects derived from the growth of titania shells on the optical properties of silver nanowires have been investigated as a function of the shell thickness. The surface plasmon resonance mode of these nanowires undergoes a gradual red shift and decreases in intensity upon systematic build-up of the dielectric cover.