Tunable near-infrared optical properties of three-layered gold-silica-gold nanoparticles

摘要

The absorption spectra of gold-silica-gold nano-shells have been investigated by using Mie theory with variation of the geometry. With an increase in core radius the plasmon resonance for the lower energy mode ω_~- shows a distinct redshift while for the high-energy mode ω_~+ shows a blueshift. It is surprising that with increasing middle layer thickness the resonance ofω_~- mode blueshifts first and then redshifts. In addition, an increase of the dielectric constant of the middle layer is found to reduce the resonance energies of the particle. The tunable near-infrared optical properties are discussed in terms of plasmon hybridization theory.