Fabrication of inert silver nanoparticles with a thin silica coating

We present a genuine experimental technique to fabricate silver nanoparticles with an ultrathin silica coating, thus making the nanoparticles chemically inert. The impact of the coating on plasmonic properties is experimentally quantified and compared with theoretical predictions. Furthermore, numerical simulations of the near-field enhancing properties of the nanoparticles are conducted. It is found that the coatings fabricated are sufficiently thin to make the plasmonic resonance wavelength shift negligible and for observing a significant field enhancement on the surface of the silica shell at the resonance wavelength. Application of such inert nanoparticles to sensitize the absorption of near-ultraviolet light is discussed.