Size-Dependent Melting of Silica-Encapsulated Gold Nanoparticles

Dick, Kimberly A.; Dhanasekaran, T; Zhang, Zhenyuan; Meisel, Dan

doi:10.1021/ja017281a

Cited by 520 publications

(423 citation statements)

References 29 publications

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“…A decrease in melting point was attributed to the diffusion of metal atoms at the surface of the metal NPs, which increases with the rise in temperature. Later on, a dependence of the melting temperature on a size of a gold NP was studied by Cleveland et al 11 and Dick et al 12 Recently, a coalescence of either silver or gold NPs was shown to take place even at room temperature 13,14 . The process, which is triggered by the removal or delocalization of the capping molecules at the surface of the NPs, takes place spontaneously once two NPs come into contact due to atom diffusion at the surface.…”

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confidence: 99%

Merging of metal nanoparticles driven by selective wettability of silver nanostructures

et al. 2014

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The welding and sintering of nanomaterials is relevant, for example, to form electrical contacts between metallic particles in printed electronic devices. Usually the welding of nanoparticles is achieved at high temperatures. Here we find that merging of two different metals, silver and gold nanoparticles, occurs on contact at room temperature. The merging process was investigated by experimental and molecular dynamics simulations. We discovered that the merging of these particles is driven by selective wettability of silver nanoparticles, independent of their size and shape (spheres or rods); silver behaves as a soft matter, whereas gold as a hard surface being wetted and retaining its original morphology. During that process, the silver atoms move towards the surface of the Au nanoparticles and wrap the Au nanoparticles in a pulling up-like process, leading to the wetting of Au nanoparticles.

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confidence: 99%

Merging of metal nanoparticles driven by selective wettability of silver nanostructures

et al. 2014

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“…The temperature is estimated as 573 K at the energy of 0.12 J according to a thermal diffusion model. 30 Figure 1(d) shows the melting of nanoparticles at a pulse energy of 0.2 J, which corresponds to a temperature of 450 C. The melting of Ag NPs is identified at this stage, which results in the remarkable shape change and coarsening of Ag NPs. Differences between thermal sintering and pulsed laser annealing are also obvious.…”

Section: Resultsmentioning

confidence: 96%

Femtosecond laser welded nanostructures and plasmonic devices

Peng

Alarifi

et al. 2012

Journal of Laser Applications

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Nanojoining, a burgeoning research area, becomes a key manufacturing of complicated nanodevices with functional prefabricated components. In this work, various nanojoining methods are first reviewed. For nanojoining of Ag/Au nanoparticles, three methods are investigated comparatively. Thermal annealing shows a two-step solid state diffusion mechanism. Laser annealing by millisecond pulses displays the thermal activated solid state diffusion. Meanwhile, two effects have been identified in femtosecond laser irradiation with different laser intensities: photofragmentation at rather high intensity (∼1014 W/cm2) and nanojoining at low intensity (∼1010 W/cm2). The photofragmentation forms a large number of tiny nanoparticles with an average size of 10 nm. Control over irradiation conditions at intensities near 1010 W/cm2 results in nanojoining of most of the nanoparticles. This nanojoining is obtained through a nonthermal melting and a surface fusion welding. Joined Au nanoparticles are expected to have numerous applications, such as probes for surface enhance Raman spectroscopy.

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“…Thus, it is significantly lowered in small particles, e.g., 1.5 nm gold particles encapsulated in silica have been observed to melt at 380 °C compared to 1086 °C for bulk gold [11]. Additionally, other related properties such as sintering and annealing show similar size dependence.…”

Section: Introductionmentioning

confidence: 99%

Influence of ligand structure on the stability and oxidation of copper nanoparticles

Kanninen¹,

Johans²,

Merta

et al. 2008

Journal of Colloid and Interface Science

245

173

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The stability and oxidation of copper nanoparticles stabilized with various ligands have been studied. Lauric acid-capped copper nanoparticles were prepared by a modified Brust-Schiffrin method. Then, ligand exchange with an excess of different capping agents was performed.Oxidation and stability were studied by UV-vis, XRD, and TEM. Alkanethiols and oleic acid were found to improve air stability. The oxidation resistance of thiol-capped copper nanoparticles was found to increase with the chain length of the thiol. However, excess thiol caused etching of the particles under nitrogen. With oleic acid no etching was observed under nitrogen. After oxidation, no traces of the ligand-exchanged particles were found, suggesting their dissolution due to excess ligand. Oleic acid protected the particles against oxidation better than the tested thiols at large excess (ligand-copper ratio 20:1).

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Size-Dependent Melting of Silica-Encapsulated Gold Nanoparticles

Cited by 520 publications

References 29 publications

Merging of metal nanoparticles driven by selective wettability of silver nanostructures

Merging of metal nanoparticles driven by selective wettability of silver nanostructures

Femtosecond laser welded nanostructures and plasmonic devices

Influence of ligand structure on the stability and oxidation of copper nanoparticles

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