Silver Electrodeposition in Amide-Based Low-Temperature Molten Salt and Its Surface-Enhanced Raman Scattering Effect

Silver film is commonly used to examine the structure and composition of molecules due to its surface-enhanced Raman scattering (SERS) effect. A simple method for preparing SERS silver films is proposed in this paper by electrodeposition in an amide-based liquid mixture (urea-acetamide-LiBr). The electrochemical behavior of silver in urea-acetamide-LiBr mixture was studied by cyclic voltammetry (CV) and chronoamperometry. It was found that the nucleation mechanism of silver shifts to instantaneous nucleation under diffusion control with increasing overpotential and temperature. The energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) investigations confirmed that the obtained deposits are pure silver. Scanning electron microscopy (SEM) analysis showed that the morphology of the silver deposits depends on the deposition potential and temperature. Rhodamine 6G was used as probe molecules for SERS experiments, showing that these new active substrates have high sensitivity to SERS response with high enhancement factors, of approximately 10⁷, and enable Raman scattering even for diluted solutions.

Keywords:
silver; urea-acetamide-LiBr; electrodeposition; SERS active