Controlled assembly of gold nanoparticles: Methods and plasmon coupling properties

Abstract

Gold nanoparticles (AuNPs) exhibit excellent plasmonic properties, including bright color and generation of localized electric field, hot carriers, and heat. These properties are widely applied in biology, sensing, spectroscopy, catalysis, and medicine. More attractive is that these properties are tremendously enhanced when AuNPs are assembled and form nanogaps between the particles. Therefore, assembling AuNPs in a controlled fashion is a key step for the study and applications of plasmonic properties. In this Account, I will introduce my group's collective efforts that have been made for a decade to develop the best assembly method. I will describe the assembly procedure in detail and demonstrate the various nanoassemblies produced by the method. The controlled assembly allows us to systematically examine the relationship between the plasmonic properties and structural parameters of the nanogaps. Among many properties, I focus on plasmon coupling. To conclude, I will discuss the prospects of nanoassembly plasmonics. The newly developed controlled assembly method allows us to prepare gold nanoparticle assemblies consisting of various nanoparticle shapes, sizes, and gap distances. Such nanoassemblies reveal the relationship between the plasmon coupling and the nanogap structural parameters. image