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 Raman 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 degrees 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 degrees C. The aging in SERS intensity is also depressed on this modified Ag substrate due to the contribution of TiO2 nanoparticles to SERS effects.