Influence of drying treatment to electrochemically roughened Ag substrates on the corresponding surface-enhanced Raman scattering performances

For obtaining metal-island films on substrates with activity of surface-enhanced Raman scattering (SERS), a controllable and reproducible surface roughness can be easily generated by using electrochemical oxidation–reduction cycle (ORC) procedures. However, different preparation procedures could significantly change their corresponding SERS activities. In this study, SERS-active Ag substrates were prepared by using triangular-wave ORC procedures in 0.1 M KCl solutions. Before the adsorptions of probe molecules on these Ag substrates one substrate was further dried in a vacuum-dryer. Interestingly, the SERS activity of this dried Ag substrate is significantly reduced due to this additional treatment. Experimental results indicate that this phenomenon can be ascribed to the correspondingly significant decrease in content of Cl-containing complexes formed on the interface of the roughened Ag metal.

► Differences in SERS effects with and without post-drying treatment are observed.
► Post-drying would reduce content of Cl-containing complexes formed on rough metal.
► Best strategy to maintain the SERS activity is to keep the formed Cl species.