Development of Novel Substrates for Surface-enhanced Raman and Surface-enhanced Hyper Raman Spectroscopy

Since its discovery two decades ago, surface-enhanced Raman scattering (SERS) has been explored extensively as a useful technique in the study of molecular behaviors at interfaces and in chemical and biochemical analysis. At solid-liquid interface, SERS has been practiced mainly in aqueous solution on either aggregated metal colloids or roughened metal electrodes. However, both aggregated metal colloids and roughened electrodes have their own problems as SERS substrates. One of the intriguing questions in exploring SERS application in chemistry is that can SERS-activity be gained and regulated from the dispersed metal nanoparticles immobilized on a SERS-inactive smooth electrode surface. The very essence of this question is to explore the effect on SERS-activity when the main features of two conventional SERS-surfaces, namely metal colloids and electrode, are combined. Same question can also be asked for the nonlinear three-photon surface-enhanced hyper Raman scattering (SEHRS).