Synthesis and theoretical calculation of Au.Ag heterometallic hybrid nanostructures

Abstract

In Part I, Ag-Au-Ag heterometallic nanowires were synthesized via a seed-mediated process from Au decahedral seeds with different sizes. In this approach, the thicknesses of the heterometallic nanowires were dependent upon the diameters of the Au decahedral seeds. The resulting Ag-Au-Ag heterometallic nanowires have the thicknesses of 61 nm, 84 nm, and 147 nm, respectively. The structures of the Ag-Au-Ag heterometallic nanowires have distinguishable Au and Ag segments in their EDS, line profile, and elemental mapping analysis. In Part II, the optical property of a single Au nanoparticle on a glass substrate was studied by a DDA(Discrete Dipole Approximation) calculation. The structures of metallic and heterometallic nanoparticles on a glass substrate were also coded using DDA method. The presence of the glass substrate leads to the red shift of the extinction peaks in a Uv-vis range. In order to study the influences of the mixed elements with Au and Ag, and their internal arrangement, various three dimensional structures including both elements, such as a Au cube, Au octahedron/Ag cube core-shell, Au cuboctahedron/Ag cube core-shell and a Ag cube were coded property. The extinction patterns of the Au octahedron/Ag cube core-shell structure were similar to those of the Ag nanocube. On the other hand, the extinction peaks of the Au cuboctahedron/Ag cube core-shell structure were similar to those of the Au nanocube.