Formation of Metallic Nanowires by Laser Ablation in Liquid Helium

We investigate the motion of electrically charged metallic nano-and microparticles produced by laser ablation in He gas and injected into superfluid helium. In the presence of a vertical static electric field, the particles either perform a repetitive shuttle-like motion transporting the charge across the liquid-gas interface or become trapped under the free surface of liquid He and coalesce into long filaments and complex two-dimensional mesoscopic networks. A classical electrohydrodynamic model is used to describe the motion of charged microparticles in superfluid He. The resulting filaments and networks are analyzed using electron microscopy. It is demonstrated that each filament is in fact composed of a large number of nanowires with a characteristic diameter of order of 10 nm and extremely large aspect ratios.

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“…6,8 In the following we concentrate on the experiments with the ablation target (either Ba or Cu) positioned in He gas above superfluid He.…”

Section: Resultsmentioning

confidence: 99%

Metallic nanowires and mesoscopic networks on a free surface of superfluid helium and charge-shuttling across the liquid–gas interface

Moroshkin

Batulin

Leiderer

et al. 2016

Phys. Chem. Chem. Phys.

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“…In particular, the gold wires have diameter of 4 nm and, despite the high melting point of bulk gold (1336 K), decayed into chains of separate nanoclusters already at room temperature [27]. Since this decay is induced by unfreezing the surface atom mobility, the nanowire temperature stability can be improved by doping the major metal by another metal that is readily oxidized in air, as was demonstrated by copper doping of silver [25,26].…”

Section: Introductionmentioning

confidence: 99%

Application of Au–Cu nanowires fabricated by laser ablation in superfluid helium as catalysts for CO oxidation

et al. 2015

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The copper-doped gold nanowires (4 nm in diameter) were produced by the novel technique based of laser ablation of Au-Cu alloy inside superfluid helium. The principle of the method is using the quantized vortices as the 1D template for the condensation of the ablation products into thin threads. The nanowires were applied as the catalyst in СО oxidation with oxygen. The activity of Au-Cu nanowires deposited on glass filters was compared with that for monometallic and bimetallic Au and Cu particles (3-8 nm in diameter) deposited on alumina by traditional deposition-precipitation and impregnation techniques. The apparent activation energies of the reaction (Еа) were 95 and 98, 150, and 147 kJ/ mol for Au-Cu nanowires and Au-Cu, Au, and Cu particles, respectively. During running-in of the Au-Cu nanowirebased catalyst, Еа decreased to 20 kJ/mol and retained at this level in the subsequent cycles of lowering and raising the reactor temperature.

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“…34 In a very different experiment, laser ablation of metals has been used to produce nanowires in bulk liquid helium. 39 In the superfluid phase, very long filaments (∼15 mm) composed of many entangled wires (thickness 2−10 nm) were produced, which were attributed to growth along quantized vortices.…”

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confidence: 99%

Preparation of Ultrathin Nanowires Using Superfluid Helium Droplets

et al. 2014

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Direct preparation of long one-dimensional (1D) nanostructures with diameters <10 nm inside superfluid helium droplets is reported. Unlike conventional chemical synthetic techniques, where stabilizers, templates, or external fields are often required to induce 1D growth, here, we exploit the use of quantized vortices to guide the formation of ultrathin nanowires. A variety of elements have been added to the droplets to demonstrate that this is a general phenomenon, including Ni, Cr, Au, and Si. Control of the length and diameter of the nanowires is also demonstrated.

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Formation of Metallic Nanowires by Laser Ablation in Liquid Helium

Cited by 34 publications

References 22 publications

Metallic nanowires and mesoscopic networks on a free surface of superfluid helium and charge-shuttling across the liquid–gas interface

Metallic nanowires and mesoscopic networks on a free surface of superfluid helium and charge-shuttling across the liquid–gas interface

Application of Au–Cu nanowires fabricated by laser ablation in superfluid helium as catalysts for CO oxidation

Preparation of Ultrathin Nanowires Using Superfluid Helium Droplets

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