Single-Crystal Electrochemistry Reveals Why Metal Nanowires Grow

Abstract

Shape-control is used to tune the properties of metal nanostructures in applications ranging from catalysts to touch screens, but the origins of anisotropic growth of metal nanocrystals in solution are unknown. We show single-crystal electrochemistry can test hypotheses for why nanostructures form and predict conditions for anisotropic growth by quantifying the degree to which different species cause facet-selective metal deposition. Electrochemical measurements show disruption of alkylamine monolayers by chloride ions causes facet-selective Cu deposition. An intermediate range of chloride concentrations maximizes facet-selective Cu deposition on single crystals and produces the highest aspect ratio nanowires in a solution-phase synthesis. DFT calculations similarly show an intermediate monolayer coverage of chloride displaces the alkylamine capping agent from the ends but not the sides of a nanowire, facilitating anisotropic growth.

Facile Synthesis of Pd−Cu Bimetallic Twin Nanocubes and a Mechanistic Understanding of the Shape Evolution

“…The large (7.1%) lattice mismatch between Cu and Pd forces the deposition of Cu to be initiated from only one of the two basal planes of a nanoplate and this asymmetric growth pattern differs from what was observed in the synthesis of monometallic Ag twin cubes from Ag nanoplates. The presence of hexadecylamine (HDA) and Cl − helps the development of six {100} facets on each Pd−Cu twin cube . When the hexagonal nanoplates are replaced with triangular ones, the products change from twin cubes to right bipyramids.…”

“…The presence of hexadecylamine (HDA) and Cl À helps the development of six {100} facets on each PdÀ Cu twin cube. [28,29] When the hexagonal nanoplates are replaced with triangular ones, the products change from twin cubes to right bipyramids. High-resolution transmission electron microscopy (HRTEM) imaging indicates that the hexagonal nanoplate contains two twin planes whereas the triangular nanoplate only contains one.…”

Flexible wearable sensors - an update in view of touch-sensing

“…Materials of flexible sensors should be lightweight, comfortable, biocompatible, and not cause irritation. Nanocomposite materials are most commonly, consisting of metallic thin films [29][30][31], metal nanowires (NWs) [32,33], carbon nanotubes (CNTs) [34][35][36], conductive polymers [37][38][39], and metal nanoparticles (NPs) [40][41][42]. Recently, the NWs, CNTs, and Nearly all of the sensor parts can be fabricated by printing.…”

Nanowire Genome: A Magic Toolbox for 1D Nanostructures

“…Based on the above developments, various “bottom‐up” strategies have been well developed to generate NWs, which is proven to be simple and efficient in controlling the chemical composition and morphology . Despite these great achievements, an efficient organization of the NWs should be proposed not only to derive the intrinsic relationship between various NWs reported previously but also to predict the synthetic strategies, properties and behaviors of undiscovered or newly synthesized NWs …”

“…[38,40] Despite these great achievements, an efficient organization of the NWs should be proposed not only to derive the intrinsic relationship between various NWs reported previously but also to predict the synthetic strategies, properties and behaviors of undiscovered or newly synthesized NWs. [41] The gene is a molecular biological concept and refers to the molecular unit of heredity. [42] The genome is an informatics term used in molecular biology and genetics, especially to interpret the heredity of an organism, and often displays as an encoded series in DNA.…”