Synthesis and Surface-Enhanced Raman Scattering Property of Pentagonal Dodecahedral Au Nanocrystals

摘要

The controlled synthesis of polyhedral Au nanocrystals (NCs) has attracted tremendous research interest in the past decades due to their promising applications in a variety of fields, such as plasmonics, sensors, electronics, catalysis, and surface-enhanced Raman scattering (SERS).1"11 Since the inherent plasmonic, electrical, and catalytic properties of Au NCs can be finely tuned by control over their shapes, numerous synthesis methods have been developed for the production polyhedral Au NCs with tailored morphologies, such as Platonic solids (tetrahedron, cube, octahedron, and icosahedron), cuboctahedron, decahedron, rod, and plate. To minimize the surface energy during the NC growth, these Au NCs are mostly enclosed by stable low-index {111} and/ or {100} facets. Recently, the synthesis of Au NCs with exposed high-energy facets, i.e., low-index {110} and high-index {hkl} (at least one index greater than 1), has been reported. NCs bound by high-energy facets have shown enhanced performance compared to conventional {111} and/ or {100}-faceted NCs due to the presence of high-density undercoordinated atoms on their surfaces as well as to their unique morphological characteristics. For instance, we reported that rhombic dodecahedral (RD) and hexocta-hedral Au NCs exclusively bound by {110} and {321} facets, respectively, exhibited pronounced SERS activities. Nevertheless, it is still a great challenge to synthesize shape-controlled NCs that are enclosed by high-index facets due to their high surface energy.