Improved surface-enhanced Raman scattering on electrochemically roughened silver substrates prepared in bielectrolyte solutions

Abstract

In this work, the effect of supplemental LiClO 4 electrolytes in KCl solutions used in roughening silver substrates by electrochemical triangular-wave oxidation–reduction cycles (ORC) on surface-enhanced Raman scattering (SERS) was first investigated. To prepare SERS-active substrates by ORC procedures, electrolytes of KCl were generally employed. In contrast, LiClO 4 ones were unsuitable for producing SERS-active substrates. Encouragingly, SERS of Rhodamine 6G (R6G) adsorbed on the roughened Ag substrate prepared in an aqueous solution containing KCl and LiClO 4 electrolytes exhibits a higher intensity by one order of magnitude, as compared with that of R6G adsorbed on a roughened Ag substrate prepared in a solution only containing KCl. Further investigations indicate that the oxidation state of Cl on the roughened Ag substrate demonstrates decided effects on this improved SERS.