Enhancements in intensity and stability of surface-enhanced Raman scattering on optimally electrochemically roughened silver substrates

Abstract

In this work, different conditions for electrochemically roughening silver substrates were investigated to obtain the best surface-enhanced Raman scattering (SERS) performance. Experimental results indicate that Ag electrodes can be cycled in deoxygenated aqueous solutions containing 0.1 N HCl from −0.3 to +0.2 V vs.Ag/AgCl at 25 mV s⁻¹ for five scans to obtain the strongest SERS effects. Using this substrate, the SERS intensity of adsorbed Rhodamine 6G (R6G) can be increased 9-fold, compared with that of R6G adsorbed on an Ag substrate prepared using the general literature methods. Moreover, the SERS enhancement capabilities of the newly developed Ag substrate seriously decays at 200 °C, compared to 125 °C for the generally roughened Ag substrates. The reduction of the SERS intensity upon aging is also lessened for this newly developed substrate. Further investigations revealed that surface morphology and the Cl content on the roughened Ag substrates have significant influence on the corresponding SERS performances.