Surface-enhanced Raman Scattering spectroscopy of organic dyes adsorbed on silver nanoparticles

Abstract

Surface-Enhanced Raman Scattering (SERS), a modern technique that dramatically enhances the Raman scattering signal of the analysts, has attracted extensive research interest. The SERS phenomenon was explained by the localized surface plasmon resonance (LSPR) of the Raman substrate. In this report, we interested in the plasmonic Raman substrate based on silver nanoparticles. In order to optimize the SERS signal, the silver nanoparticles in different shapes were synthesized and characterized by UV-vis spectrometer and Scanning electron microscope. The SERS activity of these silver nanoparticles with varying plasmon wavelength was tested with two dye molecules (Methylene blue and Rhodamine B), using visible laser excitation sources 514 nm. A maximum enhancement factor in the order of 10⁶ was obtained when the absorption peaks of analyst, the excitation line and the plasmon wavelength of the silver nanoparticles were in close approximation.