Modeling and Theoretical Analysis of the SERS Enhancement Factor Considering the Electronic Structural Energy
Xu Yang, Zhen Zhou, Qi Jia, Siqi Zhang, Kangkang Guo, Shoubo Zhao
Abstract
The enhancement factor is one of the key parameters characterizing the phenomenon of surface-enhanced Raman scattering. At present, this parameter is described by an empirical formula or a certain single physical mechanism instead of a unified model of the chemical and electromagnetic enhancement mechanisms. It is necessary to integrate the dual enhancement mechanisms of SERS to more accurately obtain the SERS enhancement factor with molecular selectivity. Therefore, we propose a quantitative model for the prediction of the enhancement factor that includes the two main contributions, metal plasmon resonance and electronic structure. Theoretical analysis and verification by experimental results prove that the new predictive enhancement factor (EF) model of electronic structural energy improves the enhancement factor by approximately 10 times and can be used to calculate the enhancement factors of different molecules on the same substrate material, which can provide molecular selectivity and more accurate EF predictions. This paper presents a theoretical model of the SERS enhancement factor that includes the adsorption of the adsorbed molecules and the surface of the substrate, combines the electromagnetic and chemical enhancement mechanisms for surface-enhanced Raman scattering, and provides a deep comprehension of the phenomenon of surface-enhanced Raman scattering.