One-Dimensional Gold Nanostructures through Directed Anisotropic Overgrowth from Gold Decahedrons

Abstract

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.

Synthesis of Monodisperse Lanthanum Hydroxide Nanoparticles and Nanorods by Sonochemical Method

“…For lanthanum hydroxide nanorods, the intensity ratio between the (100) and the (110) diffractions is 0.85, and between the (100) and the (101) diffractions is 1.19 which is significantly smaller than the conventional bulk intensity ratios (1.38 and 2.12, respectively) and lanthanum hydroxide nanoparticles ratios. This trend reveal that there is a direct relation between XRD patterns and shape of nanostructures because preferential growth of one face cause formation of specific shape and in the case of La(OH) 3 this preferential growth along the [100] direction forms 1D structure [35][36][37]. Figure 2 shows TEM image of lanthanum hydroxide nanorods, sample no.…”

Crystallographic control of noble metal nanocrystals

“…Common twinned structures of noble metal nanocrystals, such as singly twinned [10,45], multiple planar-twinned [11,[46][47][48], cyclic penta-twinned [49][50][51][52][53][54][55][56][57][58][59][60], and multiple-twinned icosahedral structures [59][60][61][62][63][64], have well-defined shapes and have been chemically synthesized. Singly twinned noble metal nanocrystals are one of the simplest twinned structures.…”

Silver/Gold Heterometallic Nanostructures and Their Surface Plasmon-related Behaviors

“…The shape guidance of the silver species on gold nanocrystal growth was also employed for gold nanorod synthesis [8]. 1/200 equiv of AgNO 3 with respect to the gold precursor concentration was added to a dispersion of gold decahedral seeds in boiling PD, and PVP and the gold precursor solutions were added to the reaction mixture, followed by heating at reflux temperature.…”