Island Growth in the Seed-Mediated Overgrowth of Monometallic Colloidal Nanostructures

Abstract

Summary Manipulating the growth mode of colloidal nanocrystals is of both fundamental interest and technological importance because it is often connected to the control of their shape, morphology, and physicochemical properties. In conventional wisdom, island growth during thin-film deposition is restricted to lattice-mismatched materials. Here, we show that deposition of Au on Au nanostructures (e.g., nanoplates, nanorods, and nanospheres) can produce separate Au islands on the seed surface with tunable size and density while preserving the original crystal structure. The island growth in the system is ascribed to the synergistic effect of fast redox kinetics and surface capping of large polymeric ligands. Decreasing the reaction rate or changing the capping ligands could readily transform the deposition of Au on Au nanostructures from island growth to layer-by-layer mode. We further take advantage of the dense hotspots of the islands-on-plate nanostructures and demonstrate their excellence in surface-enhanced Raman scattering detection.