Room-temperature mechanochemical synthesis of silver nanoparticle homojunction assemblies for the surface-enhanced Raman scattering substrate

Abstract

A room-temperature mechanochemical synthesis technique, featuring convenience and environmental friendliness, has been successfully developed to fabricate silver hierarchical architectures. The polyethylene glycol 400 was employed to assist the fabrication of silver nanoparticle assemblies with homojunctions. The result indicated that the formation of homojunction was sensitive to the feed ratio of the volume of polyethylene glycol 400 to the moles of AgNO₃. Based on the induction effect of polyethylene glycol molecules, the formation mechanism of Ag/Ag-homojunctions was proposed. The Raman scattering substrate based on these silver nanoparticle homojunction hierarchies possesses stronger Raman scattering responses for rhodamine 6G than isolated nanoparticles, which probably arise from the huge and extra enhancement of the electromagnetic field in homojunctions. These hierarchies have high stability endowing them with excellent surface-enhanced Raman scattering reproducibility. This work opens a valuable way to fabricate silver nanostructures with surface-enhanced Raman scattering activity.