Blueshift and Narrowing of Localized Surface Plasmon Resonance of Silver Nanoparticles Exposed to Plasma

We have demonstrated that plasma treatments of silver nanoparticles bring about blueshift and narrowing in their localized surface plasmon resonance. Surface-enhanced Raman scattering analysis revealed that hydrocarbons adsorbed on silver surfaces were removed effectively by plasma exposure. It was found that the decrease in Raman line intensity for hydrocarbons was correlated well with the blueshift. Our findings indicate that one of the most important factors for remarkable differences in plasmon resonance wavelengths and line widths reported for the silver nanoparticles supported on substrates between most of the experimental data and calculations by Mie's theory is due to the impurity adsorption on silver surfaces.