Geometrical Parameters Controlling Sensitivity of Nanoshell Plasmon Resonances to Changes in Dielectric Environment

Abstract

In this study, we investigate the geometrical parameters that control the sensitivity of the plasmon resonance wavelength of a silica−gold nanoshell to changes in its dielectric environment. It was found that the magnitude of the SPR frequency shift upon a change in refractive index of the embedding medium depends primarily on total nanoparticle size and less sensitively on the core/shell ratio. Immobilized nanoshells on a glass substrate showed a 25% decrease in magnitude of the SPR shifts; however, sensitivities as large as Δλ/Δn = 555.4 nm/RIU were obtained for this geometry.