Surface Deposition and Imaging of Large Ag Clusters Formed in He Droplets

Loginov, Evgeny; Gomez, Luis F.; Vilesov, Andrey F.

doi:10.1021/jp200198n

Cited by 73 publications

(112 citation statements)

References 42 publications

Supporting

Mentioning

109

Contrasting

Order By: Relevance

“…These factors offer a route to a large array of new and potentially very interesting types of nanoparticles. 29 Although still in its infancy, a number of metallic nanoparticles have been synthesized using this technique and have been removed from the helium droplets for transmission electron microscopy (TEM) investigations, including Ag/Au nanoparticles composed of ∼500 metal atoms, 30 pure Ag nanoparticles composed of over 6000 Ag atoms, 31 Ag/Au and Ni/Au core−shell nanoparticles, 32 and polycrystalline Ag nanoparticles. 33 To form 1D nanostructures in helium droplets, we will take advantage of another unique feature of superfluid helium, the presence of quantized vortices, which provide anisotropy that can guide the one-dimensional growth of particles.…”

mentioning

confidence: 99%

Preparation of Ultrathin Nanowires Using Superfluid Helium Droplets

et al. 2014

View full text Add to dashboard Cite

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.

show abstract

mentioning

confidence: 99%

Preparation of Ultrathin Nanowires Using Superfluid Helium Droplets

et al. 2014

View full text Add to dashboard Cite

show abstract

“…10 Building upon this early work, others have since explored sub-monolayer quantities of clusters made of silver, [11][12][13][14] gold, 13 and nickel, 13 as well as, binary (core-shell) cluster systems such as silver-nickel, 13 silver-gold, 13,15 and silver-silicon 16 to varying degrees of rigor.…”

Section: Introductionmentioning

confidence: 99%

Unusual behavior in magnesium-copper cluster matter produced by helium droplet mediated deposition

Emery

Xin

Ridge

et al. 2015

The Journal of Chemical Physics

View full text Add to dashboard Cite

We demonstrate the ability to produce core-shell nanoclusters of materials that typically undergo intermetallic reactions using helium droplet mediated deposition. Composite structures of magnesium and copper were produced by sequential condensation of metal vapors inside the 0.4 K helium droplet baths and then gently deposited onto a substrate for analysis. Upon deposition, the individual clusters, with diameters ∼5 nm, form a cluster material which was subsequently characterized using scanning and transmission electron microscopies. Results of this analysis reveal the following about the deposited cluster material: it is in the un-alloyed chemical state, it maintains a stable core-shell 5 nm structure at sub-monolayer quantities, and it aggregates into unreacted structures of ∼75 nm during further deposition. Surprisingly, high angle annular dark field scanning transmission electron microscopy images revealed that the copper appears to displace the magnesium at the core of the composite cluster despite magnesium being the initially condensed species within the droplet. This phenomenon was studied further using preliminary density functional theory which revealed that copper atoms, when added sequentially to magnesium clusters, penetrate into the magnesium cores.

show abstract

“…Ref. 19). It should be noted that if the doping intensity is too high, the droplets are completely destroyed and the dopants are no longer carried into the last chamber.…”

Section: Resultsmentioning

confidence: 99%

“…[18][19][20] Transmission electron microscopy (TEM) is a powerful tool for the characterization of deposited nanoparticles. The availability of aberration corrected microscopes, operating in a scanning mode (STEM), as well as very thin substrates enables the imaging of very small particles with atomic resolution.…”

Section: Introductionmentioning

confidence: 99%