DIFFERENTIAL REFLECTANCE SPECTROSCOPY AND SERS OF MILDLY ROUGHENED SILVER ELECTRODES

Differential reflectance spectroscopy has been used to measure the reflectivity of electrochemically roughened Ag electrodes in 0.1 M KC1 and 0.1 M KC1/0.05 M pyridine. The electrodes were subjected to varying anodic current densities in double-potential-step oxidation-reduction cycles. A correlation exists in both systems between SERS intensities for both v(Ag-Cl) and pyridine ring breathing vibrations and the magnitude of the decrease in reflectivity. Surfaces that exhibit the greatest decrease in reflectivity exhibit the greatest SERS intensity. Scanning electron microscopy is used to characterize surface morphology. The reflectivity spectra are interpreted in terms of absorption by large-scale Ag roughness features. The correlation between decrease in reflectivity and increased SERS intensity is proposed to be due to electromagnetic enhancement effects. © 1990, American Chemical Society. All rights reserved.