UV-Vis plasmon studies of metal nanoparticles

Abstract

Previous studies of the surface plasmon resonance (SPR) from alloy nanoparticles of gold and silver have focused on bulk studies of the nanoparticles in solution. Here, we present a selection of data observed from individual alloy nanoparticles using highly spatially resolved electron energy-loss spectroscopy (EELS). In order to resolve the SPR in both the pure gold and Au-Ag alloy nanoparticles, we successfully applied the Richardson-Lucy deconvolution routine. We found that resonances observed from different sized alloy nanoparticles do not follow the same trends in frequency variation as their pure metal equivalent. Additionally, we do not consistently observe a single SPR peak, as one might expect from an alloy nanoparticle. This indicates that alloy nanoparticles, produced by the simultaneous reduction of metal salts, cannot be considered truly homogeneous.