Structural study of citrate layers on gold nanoparticles: role of intermolecular interactions in stabilizing nanoparticles.

The structure of citrate adlayers on gold nanoparticles (AuNPs) was investigated. Infrared (IR) and X-ray photoelectron spectroscopy (XPS) analyses indicate citrate anions are adsorbed on AuNPs through central carboxylate groups. A unique structure of adsorbed citrate is determined, and a pH-induced structural transition is presented. IR analysis probes… (More)