Novel Analysis Method for the Solid-liquid Interface Using Surface Enhanced Raman Spectroscopy

Abstract

It is very important to focus on the solid-liquid interface for analysis of a variety of systems at solid-liquid interface such as electroless deposition processes. In order to avoid the influence of "bulk" solutions, we characterized reductants (i.e., hydrazine, hypophosphite, formaldehyde) adsorption on Ag surface down to the single molecular level by using plasmon antenna enhanced Raman scattering with a high-selectivity component. The concentric-patterned antenna coated with Ag, which consisted of a single hole with coaxial dimples, was designed by Finite Difference Time Domain (FDTD) calculation to enhance the electric field by focusing surface plasmon. By using this antenna and comparing the spectra to the results of Density Functional Theory (DFT) calculations, Raman peaks of adsorbed reductants on Ag were identified. These results suggest that this approach can exactly focus on the solid-liquid interface, and such in-situ characterization will be beneficial for analysis of catalytic reactions, which is one of the most difficult applications in electroless deposition processes.