Controllable Syntheses Of Gold Nanostructures

There are three main parts in this paper.We have selected 1-Dodecanethiol as a ligand to prepare colloidal gold nanoparticles with the size from 1 to 5nm.UV-vis,IR and XRD results provide the evidence for the formation of thiol-capped gold nanoparticles and heating treatment is our way to synthesize monodisperse gold nanoparticles.We have also optimized the experimental conditions to confine the size distribution such as condensation.PVP(poly(vinyl pyrrolidone))-caped micrometer-sized twinned gold (Au)plates with the shape of hexagon or triangle have been synthesized in a large quantity by reducing hydrogen tetrachloroauric acid using ethylene glycol in the presence of(PVP)molecules at 200℃under the extra condition of autogenous pressure.Clear twin boundaries in thus-obtained Au plates have been observed by scanning electron microscope(SEM).To further elucidate the mechanism of formation of twinned Au plates,transmission electron microscope(TEM)and selected area electron microscope has been employed to characterize smaller Au nanoplates obtained simultaneously with Au microplates.The characteristic of Au crystal and the absorption and desorption of PVP on the surface of Au crystal is the reason of the twinned structure.