Electroless deposition via galvanic displacement as a simple way for the preparation of silver, gold, and copper SERS-active substrates

Abstract

Plasmonic substrates can provide efficient enhancement of the local electric field, which is essential for a series of applications, including chemical sensing. Surface-enhanced Raman scattering (SERS) spectroscopy uses specific physical properties of nano-/micro-structured noble metals surfaces to amplify signals of the adsorbed analyte. Commonly used techniques for preparing large-area SERS-active substrates can be time-consuming, expensive, and technically demanding. In this study, we have produced a series of Ag, Au, Cu SERS-active substrates using wet chemical fabrication process and discussed corresponding layer growth mechanisms. The tested approach involves electroless deposition via galvanic displacement. The produced substrates were examined by scanning electron microscopy, energy-dispersive X-Ray spectroscopy, and X-ray diffraction. For SERS analysis of model analyte riboflavin, a 1064 nm excitation wavelength was used. Principal component analysis, calculation of the peak area of selected FT-SERS bands, and estimation of enhancement factors were applied to find optimal deposition time for the prepared substrates. It was confirmed that tested deposition solutions are convenient for producing large-area SERS-active substrates that provide reasonable Raman enhancement for sensing applications using near-infrared excitation. Data statistical processing showed that the intensity of measured FT-SERS spectra is less affected by a deposition time and more affected by the pH and composition of the deposition solution.