One-dimensional gold nanostructures through directed anisotropic overgrowth from gold decahedrons

One-dimensional gold nanorods were synthesized from gold decahedrons in the presence of silver ions by a systematic overgrowth approach. Both the diameters and lengths of the nanorods were independently varied by using distinct-sized decahedrons and gold precursor concentrations. The key factors of anisotropic growth are three-dimensional decahedral seed structures and energetic differentiation of the distinct facets. A series of copper and silver underpotential deposition (UPD) experiments confirmed that the silver components were mainly located on the Au(100) facets, which constitute the side walls of the nanorods. The growth mechanism of the gold nanorods could be clarified by an arbitrary elongation of the decahedral seeds and selective restriction of the {100} growth by silver UPD. Low temperature growth without silver generated very long nanowires by preferential adsorption of poly(vinyl pyrrolidone) on the {100} surface.