Search

Herein, we present a simple yet versatile single step aqueous synthesis procedure for precisely controlling the formation of hollow as well as core-shell metal nanostructures. Modern refined Turkevich protocol has been effectively utilized so as to mechanistically understand the step-by-step autocatalytic process in the monodisperse synthesis of such exotic shaped metal nanostructures. Au core with Ag shell nanoparticles were optimized by the careful addition of Ag+ ions to the pristine gold nanoparticles, the negative charge on which efficiently attracts the Ag+-cations towards their surface and simultaneously reducing them, thereby consolidating the thin shell formation with ease. The shell thickness could as well be tuned by either changing the metal seed or cation concentration. Hollow Au nanostructures were obtained by the inverse addition of Au3+-anions to the as-prepared Ag nanoparticles, thus initiating the galvanic replacement process, wherein the concurrent oxidation of Ag0 and reduction of Au3+ takes place in a cohesive manner, resulting in the final etched nanoring / porous like morphology. The structure-property functional relationship of these artificial metal nanostructures were systematically studied utilizing optical absorption and microscopy techniques. [ABSTRACT FROM AUTHOR]

Anisotropic gold nanoparticles are particularly important owing to their exciting applications in plasmonics as well as nanophotonics and biosensing. Herein, we have synthesized gold nanoplates/nanotriangles with an average side-length varying from 80 to 150 nm via a single step room-temperature solution-phase chemical reduction method utilizing predominantly the PVP-bromine interaction. The concentration of bromine as well as the surrounding reaction medium/environment plays an important role in determining the yield of gold nanoplates/nanotriangles at a given PVP to metal ratio. In the presence of bromine ions, the distinctive binding of PVP with metal salt changes owing to its conformational variations, as illustrated successfully through FTIR, optical absorption and TEM, leading to the formation of anisotropic gold nanoplates/nanotriangles. [ABSTRACT FROM AUTHOR]