Assemblies of gold icosahedra

Bilalbegović, Goranka

doi:10.1016/j.commatsci.2004.03.005

Cited by 10 publications

(4 citation statements)

References 28 publications

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“…Related but slightly separated topic concerns one‐dimensional structures that show pentagonal, icosahedral, or other non‐crystallographic symmetries. Stability and electronic and vibrational properties of such nanostructures have been the subject of many theoretical studies . In experiment, helical Au NWs with a heptagonal outer shell () and AuAg binary alloy NWs consisting of an icosahedral packing of atoms () have been observed by electron microscopy.…”

Section: Introductionmentioning

confidence: 99%

Formation of icosahedral nanowires

Fujita

Kurokawa

Sakai

2016

Physica Status Solidi (b)

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An icosahedral nanowire (INW) is a one‐dimensional structure where a single atom and a five‐membered ring are alternating to form a −1−5−1−5−1− stacking. The 1−5−1−5−1 segment of this stacking forms an icosahedron and constitutes the unit cell of an INW. In molecular dynamics (MD) simulations of stretching of metal nanowires (NWs), INWs are frequently formed at their deformation necks. Previous simulations found that the formation of INWs is more favored for thin NWs than thick NWs. To closely investigate this size dependence of INW formation, we have carried out stretching simulations of Mg NWs and examined the creation of icosahedral arrangement of atoms at their deformation necks. Our results show that thin NWs tend to produce slender necks, the atoms of which first become disordered and then rearrange themselves into an icosahedral arrangement. Thick nanowires rarely form such slender necks and this accounts for their low yield of INWs. We have also investigated a continuous and bond‐conserving process that converts the HCP arrangement of atoms into an icosahedral one. We found that the nearest‐neighbor bonds are not conserved and only a small fraction of nearest‐neighbor atoms in an icosahedral unit cell are initially nearest neighbors.

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Section: Introductionmentioning

confidence: 99%

Formation of icosahedral nanowires

Fujita

Kurokawa

Sakai

2016

Physica Status Solidi (b)

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“…In a recent work, Haji-Akdari et al 9 have shown that packing of tetrahedra will result in quasicrystalline phases; in particular they report the forming of a decagonal quasicrystal. The packing of icosahedra was discussed theoretically by Bilalbejovic, 10 using Monte Carlo calculations to study the aggregation, and it was found that linear, nanowire-like structures are produced. However, no mention is made of any connection with the BCB helices.…”

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confidence: 99%

Experimental Evidence of Icosahedral and Decahedral Packing in One-Dimensional Nanostructures

et al. 2011

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The packing of spheres is a subject that has drawn the attention of mathematicians and philosophers for centuries, and that currently attracts the interest of the scientific community in several fields. At the nanoscale, the packing of atoms affect the chemical and structural properties of the material, and hence, its potential applications. This report describes the experimental formation of five-fold nanostructures by the packing of interpenetrated icosahedral and decahedral units. These nanowires, formed by the reaction of a mixture of metal salts (Au and Ag) in the presence of oleylamine, are obtained when the chemical composition is specifically Ag/Au=3/1. The experimental images of the icosahedral nanowires have a high likelihood with simulated electron micrographs of structures formed by two or three Boerdijk-Coxeter-Bernal helices roped on a single structure, whereas for the decahedral wires, simulations using a model of adjacent decahedra match the experimental structures. To our knowledge, this is the first report of the synthesis of nanowires formed by the packing of structures with five-fold symmetry. These icosahedral nanowire structures remind those of quasicrystals that can only be formed if at least two atomic species are present and in which icosahedral and decahedral packing has been found for bulk crystals.

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“…The dip coating method for preparing thin films is commonly used and models for thin-film formation have been obtained for sol-gel techniques. [20][21][22] Recent work has demonstrated the usefulness of dip coating in the low-speed, lowviscosity limit of EVCD, [15][16][17]23 but the process has yet to be theoretically described, except for the case in which the substrate is horizontal. 24 We have created a quantitative empirical description of the deposition process by simply considering the Brownian motion of nanoparticles in the reduced-dimension, meniscus region of the solution ͑see Fig 1͒. This model is useful for optimizing the deposition conditions necessary to obtain desired film morphologies and thicknesses.…”

Section: Theoretical Analysismentioning

confidence: 99%

Theoretical analysis of vertical colloidal deposition

Diao

Hutchison²,

Luo³

et al. 2005

The Journal of Chemical Physics

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We have modeled the dynamics of a relatively new deposition technique, vertical colloidal deposition (VCD), for preparing nanoparticle thin films. In this process, the substrate is placed vertically in a nanoparticle suspension and is gradually exposed by evaporation or other slow solvent removal. During the film's formation, we observe that the colloidal particles are deposited only at the solid-liquid-gas interface. In contrast with the horizontal geometry, treated elsewhere, where the meniscus is pinned, we observe qualitatively different deposition behaviors. In particular, uniform films rather than rings or lines are produced. Thus, we are led to model a diffusion-driven rather than a convection-driven film growth kinetics, and we are able to predict, consistent with our experimental observations, that the film's areal density is inversely proportional to the descent speed of the suspension surface. Additionally, we find that for submonolayer films, the areal density is proportional to the square of the suspension concentration, converting to a linear dependence once monolayer coverage is attained.

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Assemblies of gold icosahedra

Cited by 10 publications

References 28 publications

Formation of icosahedral nanowires

Formation of icosahedral nanowires

Experimental Evidence of Icosahedral and Decahedral Packing in One-Dimensional Nanostructures

Theoretical analysis of vertical colloidal deposition

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