Computational calculations of local field and SERS enhancement factors using Mie theory

Abstract

Surface-Enhanced Raman Spectroscopy (SERS) is based on the amplification of Raman signals. One of the enhancement mechanisms is explained by the plasmon resonance of metal nanostructures. This work consists of the computational calculation, using Mie theory, of the Local Field Enhancement Factor (LFIEF) and the SERS Enhancement Factor (SERS EF ) for an electric dipole signal close to a single metallic nanosphere (NP). Different sizes of silver, gold and aluminum NP suspended in ethanol, N,N-dimethylformamide, and ch loroform were analyzed. The results show that the intensification peak agrees with the excitation wavelength for the respective plasmon resonance of each metal. It is evident that the size of the NP influences the magnitude of the intensity obtained ; in ad dition, it is observed that the medium in which they are suspended produces a shift of the intensification peaks. For aluminum NP, an intensification peak around 200 nm suggests its possible use as a base for SERS substrate using ultraviolet excitation.