Design of gold hybrid nanostructures for nanoplasmonics

Abstract

Noble metal nanocrystals have morphology-dependent optical properties that have been the subject of extensive studies. These nanostructures exhibit a strong extinction range of UV-visible-near IR that is not present in the spectrum of the bulk metal. Gold nanocrystals have been intensively studied in recent years for various applications including photonics, chemical and biological sensing, and imaging, on the basis of their localized surface plasmon resonances. In order to employ gold nanocrystals as a scaffold for applications, both the morphology control of nanocrystals and the introduction of appropriate functionality on the nanocrystal surface must be fulfilled. We have synthesized numerous gold nanostructures such as decahedrons, icosahedrons, spheres, cubes, octahedrons, rods, wires by a modified polyol process. The rapid reduction of gold precursors in refluxing long chain diol has successfully provided a series of gold nanocrystals in the shape of octahedra, truncated octahedra, cuboctahedra, cubes, and higher polygons by incremental changes of silver nitrate concentration. We expect that the silver species generated from $AgNO_3$ seemed to determine the final nanocrystal morphology by the selective growth of {111} and/or the restriction of {100}. Silver underpotential deposition (UPD) experiments confirmed that the silver components were mainly located on the Au (100) facets. Heterostructured nanocrystals containing multiple components attract critical attention due to not only their multifunctional properties but also new features raised from the effective coupling of different domains. Therefore we prepared Au based hybrid nanostructures such as Ag-Au-Ag heterometallic nanorods, Au/Ag Asymmetric Hollow Nanorod, Au-semiconductor hybrid nanostructures, and Au-Polymer hybrid Nanostructures. Using this advanced synthetic strategy, we should focus on the control of hybrid nanomaterials for the development of new and improved various applications. Espec...