Novel surface-enhanced Raman scattering-active silver substrates containing visible light-responsible Tio₂ nanoparticles

We report here the first electrochemically prepared surface-enhanced Raman scattering (SERS)-active silver substrates containing visible light-responsible TiO₂ nanoparticles. The SERS-active Ag substrates with TiO₂ nanoparticles were prepared by roughening the substrates using electrochemical oxidation-reduction cycles (ORC) in 0.1 M HCl aqueous solutions containing 1 mM visible light-responsible TiO₂ nanoparticles. Based on these prepared substrates, the SERS of Rhodamine 6G (R6G) exhibits a higher intensity by one order of magnitude, as compared with that of R6G adsorbed on a roughened Ag substrate without TiO₂ nanoparticles. Moreover, the practical limit of detection (LOD) of R6G can be reduced by five orders of magnitude from 2 × 10^-10 to 2 × 10^-15 M owning to the additional contribution of TiO₂ nanoparticles to the whole SERS effects.