Improved performances on surface-enhanced Raman scattering based on electrochemically roughened gold substrates modified with SiO₂ nanoparticles

In this work, we use electrochemical oxidation-reduction cycles (ORC) methods to prepare surface-enhanced Raman scattering (SERS)-active gold substrates modified with SiO₂ nanoparticles to improve the corresponding SERS performances. Based on the modified substrates, the SERS of Rhodamine 6G (R6G) exhibits a higher intensity by 3-fold of magnitude, as compared with that of R6G adsorbed on a SERS-active Au substrate without the modification of SiO₂ nanoparticles. Moreover, the SERS enhancement capabilities of the modified and the unmodified Au substrates are seriously destroyed at temperatures higher than 250 and 200°C, respectively. These results indicate that the modification of SiO₂ nanoparticles can improve the thermal stability of SERS-active substrates. The aging in SERS intensity is also depressed on this modified Au substrate due to the contribution of SiO₂ nanoparticles to SERS effects.