High-yield colloidal synthesis of monometallic Au nanorod-Au nanoparticle dimers and their application in SERS

Abstract

Dimeric nanostructures have attracted much attention owing to their unique structure and excellent physiochemical properties. However, it has been very difficult to make monometallic nanodimers. In this work, we report a simple colloidal approach to synthesize high-yield monometallic Au nanorod-Au nanoparticle dimers by using a negatively charged polyelectrolyte, poly(sodium-p-styrenesulfonate) (PSS), to modify the positively charged Au nanorods. The growth process is studied by systematically tuning the reaction parameters. The as-obtained dimers can serve as a great SERS substrate for the detection of organic molecules because of the existence of “hot-spots”. The analytical enhancement factor (AEF) of the as-prepared dimers is up to 106, which is two magnitudes higher than that of Au nanorods.