Polyelectrolyte Multilayer-Mediated Growth of Gold Nanoparticle Films with Tunable Loading Density and Nanoparticle Shape

A facile method for preparing gold nanoparticle (AuNP) films with a high loading density based on the seed-mediated growth of AuNPs on a polyelectrolyte multilayer (PEM) is reported. Use of PEMs as a base layer for gold seed adsorption confers controllability on the loading density of the AuNP film and size of the resulting AuNPs. In addition, the shape of the final AuNPs could be varied by adapting various species of polyelectrolytes. The optical response of the AuNP films is stable, because of the relatively uniform distribution of the AuNPs over a large area. The AuNP film has been used as a substrate for surface-enhanced Raman scattering (SERS), and it shows stable and reproducible enhancement in the range from 10 5 to 10 7 depending on the fabrication condition.