Optical properties of core-shell Ag@Au and Au@Ag nanoparticles

The optical properties of spherical, bimetallic: (core-shell) plasmonic nanostructures made of gold and silver were studied. The simulations were performed using the boundary element method. The refractive index sensitivity (RIS) of the nanoparticles was calculated from the peak shift in the extinction spectrum due to the change of the surrounding medium's refractive index. The effect of the particle's material, the size of the core, and the shell on the extinction spectrum and the RIS were investigated and they were compared with the data of the pure spherical nanoparticles.