Varying SiO2 thickness of core–shell noble-grains on a gradient sensing plate to enhance field Raman scattering

Abstract

This study demonstrates a strong surface-enhanced Raman scattering (SERS) of crystal violet (CV) dye by using SiO2 shell/Ag core nanoparticle in gradient-size surface plate. The excitation of CV dye can be enhanced by the localized surface plasmons of Ag core/shell SiO2 grains due to electromagnetic (EM) enhancement induced. For SERS resonance, the change of dielectric environment of grains results in red shift and magnification of spectra in varying SiO2 thickness. Herein, the enhanced SERS conducted the core/shell grain with an SiO2 thickness of 8.7 nm to magnify the intensity about 83 %-fold that is a direct evidence in enhanced charge transport and mutative dielectric environment.