Chem
Volume 3, Issue 4, 12 October 2017, Pages 678-690
Journal home page for Chem

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

https://doi.org/10.1016/j.chempr.2017.08.004Get rights and content
Under an Elsevier user license
open archive

Highlights

  • Island growth has been achieved in a monometallic Au system without lattice mismatch

  • Island growth is enabled by controlled crystal-growth kinetics and surface properties

  • Island growth opens a way to novel monometallic nanocrystals with intriguing properties

The Bigger Picture

Noble-metal nanocrystals find broad application in sensing, imaging, and catalysis, and their performance is heavily dependent on the nanostructures. Until now, general rules of crystal growth have been established and constitute the current wisdom in the structural design of noble-metal nanocrystals. For example, island growth of a metal on nanocrystals of another metal is usually induced by lattice mismatch between the two metals. However, in many cases, great possibilities lie beyond these rules for discovering new nanostructures with intriguing properties and applications. Here, we demonstrate this possibility by establishing a mechanism that allows an unusual island-growth mode of monometallic Au without involving any lattice mismatch. It enables production of a family of Au island structures, which showed superior performance in surface-enhanced Raman scattering. Our findings could inspire further efforts in building sophisticated metal nanostructures.

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.

UN Sustainable Development Goals

SDG9: Industry, innovation, and infrastructure

Keywords

plasmonic nanostructures
island growth
layer-by-layer growth
reaction kinetics
ligand exchange
surface-enhanced Raman scattering

Cited by (0)

7

Lead Contact