Search results for "nanoclusters"

Innentitelbild: Poly(polyoxotungstate)s with 20 Nickel Centers: From Nanoclusters to One-Dimensional Chains (Angew. Chem. 39/2009)

2009

Poly(polyoxotungstate)s with 20 Nickel Centers: From Nanoclusters to One-Dimensional Chains

2009

ChemInform Abstract: Poly(polyoxotungstate)s with 20 Nickel Centers: From Nanoclusters to One-Dimensional Chains.

2009

ODS ferritic steels obtained from gas atomized powders through the STARS processing route: Reactive synthesis as an alternative to mechanical alloying

2018

Authors acknowledge ALBA synchrotron (Spain) for the provision of beamtime on the beam line BL22-CLAESS (Proposal 2016081797). Transmission electron microscopy observations were accomplished at Centro Nacional de Microscopía Electrónica, CNME-UCM. This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014–2018 under grant agreement No 633053. The views and opinions expressed herein do not necessarily reflect those of the European Commission. Financial support from Basque Government through the ELKARTEK ACTIMAT 2016 project is also acknowledged.

Birth of the Localized Surface Plasmon Resonance in Monolayer-Protected Gold Nanoclusters

2013

Gold nanoclusters protected by a thiolate monolayer (MPC) are widely studied for their potential applications in site-specific bioconjugate labeling, sensing, drug delivery, and molecular electronics. Several MPCs with 1-2 nm metal cores are currently known to have a well-defined molecular structure, and they serve as an important link between molecularly dispersed gold and colloidal gold to understand the size-dependent electronic and optical properties. Here, we show by using an ab initio method together with atomistic models for experimentally observed thiolate-stabilized gold clusters how collective electronic excitations change when the gold core of the MPC grows from 1.5 to 2.0 nm. A …

Impacts of Copper Position on the Electronic Structure of [Au25-xCux(SH)18]− Nanoclusters

2015

Here, we use density functional theory to model the impact of heteroatom position on the optoelectronic properties of mixed metal nanoclusters. First, we consider the well-described [Au25(SH)18]− motif, and substitute Cu atoms at the three geometrically unique positions within the cluster. These clusters are atomically precise and show an electronic structure that is a function of both composition and heteroatom position. We then model clusters containing Cu substitutions at two positions, and demonstrate an additional and significant impact from heteroatom proximity with respect to one another. For each system, we report the formation energy, HOMO–LUMO gap, and energy level structure, and …

Formation and evolution of self-organized Au nanorings on indium-tin-oxide surface

2011

This work reports on the formation of Au nanoclusters and on their evolution in nanoring structures on indium-tin-oxide surface by sputtering deposition and annealing processes. The quantification of the characteristics of the nanorings (surface density, depth, height, and width) is performed by atomic force microscopy. The possibility to control these characteristics by tuning annealing temperature and time is demonstrated establishing relations which allow to set the process parameters to obtain nanostructures of desired morphological properties for various technological applications. © 2011 American Institute of Physics.

Cd12Ag32(SePh)36: Non-Noble Metal Doped Silver Nanoclusters

2019

While there are numerous recent reports on doping of a ligand-protected noble metal nanocluster (e.g., Au and Ag) with another noble metal, non-noble metal (e.g., Cd) doping remains challenging. Here, we design a phosphine-assisted synthetic strategy and synthesize a Cd doped Ag nanocluster, Cd12Ag32(SePh)36 (SePh: selenophenolate), which exhibits characteristic UV–vis absorption features and rare near-infrared (NIR) photoluminescence at ∼1020 nm. The X-ray single crystal structure reveals an asymmetric two-shell Ag4@Ag24 metal kernel protected by four nonplanar Cd3Ag(SePh)9 metal–ligand frameworks. Furthermore, the electronic structure analysis shows that the cluster is a 20-electron “supe…

Water-Soluble Naked Gold Nanoclusters Are Not Luminescent.

2017

We report here the synthesis of water-dispersible naked gold nanoclusters (AuNCnaked) by a simple reduction of HAuCl4 with NaOH at room temperature and show that they are non-luminescent. They were then easily passivated with different thiols and adenosine monophosphate to lead to luminescent NCs. This is an important finding as the photoluminescence of the passivated NCs can now be clearly attributed to the ligand-AuNC surface interaction. These results are also highly relevant from the point of view of the preparation of luminescent NCs from the same NC batch. This strategy can be valuable for the preparation of a broad range of nano(bio)composites.

The evolution of the fraction of Er ions sensitized by Si nanostructures in silicon-rich silicon oxide thin films

2009

Photoluminescence (PL) and time-resolved PL experiments as a function of the elaboration process are performed on Er-doped silicon-rich silicon oxide (SRO:Er) thin films grown under NH(3) atmosphere. These PL measurements of the Er(3+) emission at 1.54 microm under non-resonant pumping with the Er f-f transitions are obtained for different Er(3+) concentrations, ranging from 0.05 to 1.4 at.%, and various post-growth annealing temperatures of the layers. High resolution transmission electron microscopy (HRTEM) and energy-filtered TEM (EFTEM) analysis show a high density of Si nanostructures composed of amorphous and crystalline nanoclusters varying from 2.7 x 10(18) to 10(18) cm(-3) as a fun…