A Simple Entropic‐Driving Separation Procedure of Low‐Size Silver Clusters, Through Interaction with DNA

Knowledge of the function and structure of small metal clusters is one goal of research in catalysis. One important experimental parameter is cluster size. Ideally, one would like to produce metal clusters of regulated size in order to characterize size-dependent cluster properties.A source has been developed which is capable of producing microscopic metal clusters of controllable size (in the range 5-500 atoms) This source, the Multiple Expansion Cluster Source, with a Free Jet Deceleration Filter (MECS/FJDF) operates as follows. The bulk metal is heated in an oven to give controlled concentrations of monomer and dimer which were expanded sonically. These metal species were quenched and condensed in He and filtered to produce areosol particles of a controlled size as verified by mass spectrometer measurements. The clusters were caught on pre-mounted, clean carbon films. The grids were then transferred in air for microscopic examination. MECS/FJDF was used to produce two different sizes of silver clusters for this study: nominally Ag6 and Ag50.

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Comparison of TEM and STM observations of small silver clusters on different carbon supports

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010017445x ◽

1990 ◽

Vol 48 (4) ◽

pp. 264-265

Author(s):

Bernd Tesche ◽

Tobias Schilling

Keyword(s):

Vibration Isolation ◽

Pyrolytic Graphite ◽

Carbon Film ◽

Silver Clusters ◽

Carbon Supports ◽

Stacking Order ◽

System P ◽

High Resolution Tem ◽

High Degree ◽

Degree Of Order

The objective of our work is to determine:a) whether both of the imaging methods (TEM, STM) yield comparable data andb) which method is better suited for a reliable structure analysis of microclusters smaller than 1.5 nm, where a deviation of the bulk structure is expected.The silver was evaporated in a bell-jar system (p 10−5 pa) and deposited onto a 6 nm thick amorphous carbon film and a freshly cleaved highly oriented pyrolytic graphite (HOPG).The average deposited Ag thickness is 0.1 nm, controlled by a quartz crystal microbalance at a deposition rate of 0.02 nm/sec. The high resolution TEM investigations (100 kV) were executed by a hollow-cone illumination (HCI). For the STM investigations a commercial STM was used. With special vibration isolation we achieved a resolution of 0.06 nm (inserted diffraction image in Fig. 1c). The carbon film shows the remarkable reduction in noise by using HCI (Fig. 1a). The HOPG substrate (Fig. 1b), cleaved in sheets thinner than 30 nm for the TEM investigations, shows the typical arrangement of a nearly perfect stacking order and varying degrees of rotational disorder (i.e. artificial single crystals). The STM image (Fig. 1c) demonstrates the high degree of order in HOPG with atomic resolution.

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Surface treatment with silver particles isles on Titanium cp: study of antimicrobial activity

Research Society and Development ◽

10.33448/rsd-v9i4.2662 ◽

2020 ◽

Vol 9 (4) ◽

pp. e27942662

Author(s):

Patrícia Capellato ◽

Cláudia Eliana Bruno Marino ◽

Gilbert Silva ◽

Lucas Victor Benjamim Vasconcelos ◽

Rodrigo Perito Cardoso ◽

...

Keyword(s):

Antimicrobial Activity ◽

Surface Treatment ◽

Titanium Surface ◽

Silver Clusters ◽

Silver Particles ◽

Silver Deposition ◽

Dispersed Particles ◽

Significant Difference ◽

Diffusion Assay ◽

Antibacterial Potential

During the last decades, researchers have been growing the interest in surface treatment with an antimicrobial agent. Silver nanoparticles (AgNPs) are widely used in biomedical fields due to their potent antimicrobial activity. So, in this study was investigated silver particles (isles) coated on titanium surface for dental and orthopedic application. Silver particles coating process on titanium surface were performed via sputtering that is a plasma-assisted deposition technique with and titanium without treatment was applied as comparing standard. Plasma treatment parameters were optimized so that the result was not a thin film of Ag but dispersed particles of Ag on the Ti-cp surface. The alloy surfaces were investigated using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). In order to investigate antibacterial potential Staphylococcus aureus and Escherichia coli have been used at Agar diffusion assay. The results were analyzed by analysis of variance (ANOVA) in order to verify significant difference antimicrobial activity between samples that have shown no difference between the surfaces studied treatments. For silver deposition scattered particles (isles) over titanium surface for a 10-minute treatment, EDS revealed by silver clusters that the particles were not properly scattered onto surface, hence, the low effectiveness in antibacterial activity.

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Quantum-chemical analysis of small silver clusters

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19871652 ◽

1987 ◽

Vol 52 (7) ◽

pp. 1652-1657 ◽

Cited By ~ 2

Author(s):

Grigorii V. Gadiyak ◽

Yurii N. Morokov ◽

Mojmír Tomášek

Keyword(s):

Hard Spheres ◽

Electronic Configuration ◽

Close Packing ◽

Basis Sets ◽

Silver Clusters ◽

Quantum Chemical Analysis ◽

Spin Distribution ◽

Spin Polarized ◽

Atomic Silver ◽

Equilibrium Geometries

Total energy calculations of three- and four-atomic silver clusters have been performed by the spin-polarized version of the CNDO/2 method to get the most stable equilibrium geometries, atomization energies, and charge and spin distribution on the atoms for three different basis sets: {s}, {sp}, and {spd}. When viewed from the equilateral triangle and square geometries, the last electronic configuration, i.e. the {spd} one, appears to be most stable with respect to the geometrical deformations considered. In this case, the behaviour of the atoms of both clusters resembles that of hard spheres (i.e. close-packing).

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Luminescence properties of laser-induced silver clusters in borosilicate glass

Optical Materials ◽

10.1016/j.optmat.2019.109618 ◽

2020 ◽

Vol 100 ◽

pp. 109618 ◽

Cited By ~ 2

Author(s):

N. Nedyalkov ◽

A. Dikovska ◽

M. Koleva ◽

N. Stankova ◽

R. Nikov ◽

...

Keyword(s):

Borosilicate Glass ◽

Luminescence Properties ◽

Silver Clusters

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ChemInform Abstract: Reduction of Ag+ in Aqueous Polyanion Solution: Some Properties and Reactions of Long-Lived Oligomeric Silver Clusters and Metallic Silver Particles.

ChemInform ◽

10.1002/chin.199112024 ◽

2010 ◽

Vol 22 (12) ◽

pp. no-no

Author(s):

A. HENGLEIN ◽

T. LINNERT ◽

P. MULVANEY

Keyword(s):

Metallic Silver ◽

Silver Clusters ◽

Silver Particles

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Optical Properties of Sputtered Silver Granular Films

Materials Science Forum ◽

10.4028/www.scientific.net/msf.480-481.287 ◽

2005 ◽

Vol 480-481 ◽

pp. 287-292 ◽

Cited By ~ 2

Author(s):

S.E. Paje ◽

F. Teran ◽

J.M. Riveiro ◽

J. Llopis ◽

M.A. García ◽

...

Keyword(s):

Silver Nanoparticles ◽

Optical Properties ◽

Optical Absorption ◽

Surface Morphology ◽

Silver Clusters ◽

Plasmon Excitation ◽

Granular Films ◽

Silver Films ◽

Atomic Force ◽

Atomic Force Micrographs

In this research we study optical absorption and morphology of silver films prepared with a sputtering method. Silver granular films are obtained on a glass substrate for films with thickness smaller than about 60 Å. Superficial silver clusters of around 100 nm in diameter are clearly seen in the atomic force micrographs. The absorption of these samples are characterized by plasmon excitation in the 450-650 nm spectral range, which differs from the known excitation of silver nanoparticles fabricated by different techniques. The optical absorption of silver granular films depend on sputtering conditions like substrate temperature or deposition rate and correlates with the surface morphology.

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Shell engineering to achieve modification and assembly of atomically-precise silver clusters

Chemical Society Reviews ◽

10.1039/d0cs01393e ◽

2021 ◽

Author(s):

Yan Jin ◽

Chong Zhang ◽

Xi-Yan Dong ◽

Shuang-Quan Zang ◽

Thomas C. W. Mak

Keyword(s):

Silver Clusters

This tutorial review focuses on the modification and assembly of atomically-precise silver clusters by changing shell layers for more stability and functionalities, especially for brighter luminescence.

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