Effect of TiO₂ nanoparticles on the improved performances on electrochemically prepared surface-enhanced raman scattering-active silver substrates

In this work, we use electrochemical oxidation-reduction cycles (ORC) methods to prepare surface-enhanced Roman scattering (SERS)-active silver substrates modified with TiO₂ nanoparticles to improve the corresponding SERS performances. On the basis of the modified substrates, the SERS of Rhodamine 6G (R6G) exhibits a higher intensity by 4-fold of magnitude, as compared with that of R6G adsorbed on a SERS-active Ag substrate without the modification of TiO₂ nanoparticles. Moreover, the SERS enhancement capabilities of the modified and the unmodified Ag substrates are seriously destroyed at temperatures higher than 200 and 125°C, respectively. These results indicate that the modification of TiO₂ nanoparticles can improve the thermal stability of SERS-active substrates. More interestingly, the SERS intensity of R6G was significantly increased by 9-fold of magnitude, as the temperature of the modified Ag substrate was raised from 25 to 125°C. The aging in SERS intensity is also depressed on this modified Ag substrate due to the contribution of TiO₂ nanoparticles to SERS effects.