Electrochemical Seed-Mediated Growth of Surface-Enhanced Raman Scattering Active Au(111)-Like Nanoparticles on Indium Tin Oxide Electrodes

In this article, a novel electrochemical seed-mediated method has been proposed for the fabrication of surface-enhanced Raman scattering (SERS) active gold nanoparticle films deposited on indium tin oxide electrodes. First, due to the fact that a high overpotential and a short time of potentiostatic transient are applied in the nucleation stage, the high controllability with the density and the size of gold nanoparticles on an indium tin oxide (ITO) electrode are realized. Second, due to the fact that AuCl4–ions will be preferentially reduced and deposited on the previously formed Au seeds in a subsequent cyclic voltammetrical process, we achieve the size-controlled gold nanoparticles which are enriched in Au(111) facet orientation (ca. 80.7%). With the growth of the nanoparticles, the gap between the adjacent nanoparticles gradually decreases, and thus plenty of “hot spots” are formed on the substrate for SERS applications. Third, by using 4-mercaptobenzoic acid as a probe molecule, the enhancement factor of the as-prepared substrate is estimated as ∼1.3 × 106, and its reproducibility and stability for SERS measurements are also evaluated. These works reveal its great potential in routine SERS applications for microanalysis. The protocol for the fabrication of such a SERS substrate is facile and cost-effective, without introducing any template or surfactant.