Ordered Colloidal Nanoalloys

Kiely, C. J.; Fink, J.; Zheng, Jian Guo; Brust, Mathias; Bethell, Donald; Schiffrin, David J.

doi:10.1002/(sici)1521-4095(200005)12:9<640::aid-adma640>3.3.co;2-a

Cited by 52 publications

(70 citation statements)

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“…Furthermore, the mixture of Au@DTBE and Ag@DTBE naoparticles has been attached at water/toluene interfaces, leading to nanoalloy films (Figure 2 b). Their TEM images reveal random close‐packing arrays, in which, however, one has difficulty in identifying the chemical identity of the nanoparticles based on the contrast level in the bright field image 4a. Moreover, we observed that the transmitted and reflected color of the resultant nanoalloy films varied with the molar ratio of Au@DTBE to Ag@DTBE nanoparticles.…”

Section: Methodsmentioning

confidence: 89%

Directing Self‐Assembly of Nanoparticles at Water/Oil Interfaces

et al. 2004

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Finding the right angle: The contact angle of nanoparticles at the water/oil interface can be engineered close to 90° by capping with ligands containing carboxylic ester terminal groups. This drives the nanoparticles to self‐assemble into close‐packed films (see picture), and thus provides the opportunity to create two‐ or three‐dimensional homo‐ or heterogeneous nanostructures for electronic, optoelectrical, and magnetic applications.

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Section: Methodsmentioning

confidence: 89%

Directing Self‐Assembly of Nanoparticles at Water/Oil Interfaces

et al. 2004

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“…Kiely and co-workers describe such arrays in several references. 118,119 A strange aspect of these arrays is that a ratio of Au : Ag of at least 10 : 1 was necessary to observe these ordered regions. Of course, the vast majority of the TEM grid shown consisted of disordered structures, so formation of such complete films is not developed.…”

Section: Formation and Physical Properties Of Metal Nanocluster Arraysmentioning

confidence: 99%

Synthesis, structure and properties of metal nanoclusters

2006

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Metal nanoclusters have physical properties differing significantly from their bulk counterparts. Metallic properties such as delocalization of electrons in bulk metals which imbue them with high electrical and thermal conductivity, light reflectivity and mechanical ductility may be wholly or partially absent in metal nanoclusters, while new properties develop. We review modern synthetic methods used to form metal nanoclusters. The focus of this critical review is solution based chemical synthesis methods which produce fully dispersed clusters. Control of cluster size and surface chemistry using inverse micelles is emphasized. Two classes of metals are discussed, transition metals such as Au and Pt, and base metals such as Co, Fe and Ni. The optical and catalytic properties of the former are discussed and the magnetic properties of the latter are given as examples of unexpected new size-dependent properties of nanoclusters. We show how classical surface science methods of characterization augmented by chemical analysis methods such as liquid chromatography can be used to provide feedback for improvements in synthetic protocols. Characterization of metal clusters by their optical, catalytic, or magnetic behavior also provides insights leading to improvements in synthetic methods. The collective physical properties of closely interacting clusters are reviewed followed by speculation on future technical applications of clusters. (125 references).

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“…Nanoalloys are formed from the nanoscale co-aggregation of two or more metals with the ability to form compositionally-ordered phases or superstructures, the properties of which are unlike those of the individual types of clusters or of bulk alloys of the constituent metals. [1][2][3][4][5] Nanoalloy systems may be synthesized by the co-transformation and co-aggregation of different metallic precursors. [6][7][8][9][10][11][12][13] For example, gold and silver nanoalloys have been produced by the reduction of gold and silver chlorides in the presence of thiol molecules, to form particles of well-defined sizes.…”

Section: Introductionmentioning

confidence: 99%

“…[6][7][8][9][10][11][12][13] For example, gold and silver nanoalloys have been produced by the reduction of gold and silver chlorides in the presence of thiol molecules, to form particles of well-defined sizes. 5 The ratio of the gold and silver nanoclusters in this system ultimately determines the equilibrium three-dimensional nanoalloy structure and hence very interesting structures could be formed by using specific cluster sizes. Other researchers have developed methods to form clusters containing a mixture of gold and silver, 14 where each cluster contains both gold and silver atoms.…”

Section: Introductionmentioning

confidence: 99%

FeCo nanoalloy formation by decomposition of their carbonyl precursors

et al. 2005

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In this paper we describe the synthesis of iron and cobalt nanoalloys by the co-decomposition of iron and cobalt carbonyl precursors in the presence of polystyrene as a surface stabilizing agent. In order to prevent the preferential aggregation of metal atoms in the iron-cobalt nanoalloys, which results in phase segregation, the decomposition kinetics of the Fe(CO) 5 and Co 2 (CO) 8 precursors had to be firmly established and controlled. The kinetics of cobalt cluster formation have been thoroughly investigated and documented, but data for Fe(CO) 5 decomposition are relatively scarce. To fully explore the kinetic characteristics of the formation of iron nanoclusters, initial Fe(CO) 5 concentrations and reaction media solvents were varied and hence reaction order and rate constants were established. Our results suggest that this decomposition is a higher-order process (not first-order as previously assumed), with a complicated intermediate mechanism, which has been postulated and experimentally verified. By using this kinetic data, we were able to predict the necessary conditions for the in situ creation of new iron-cobalt nanoalloys using carbonyl precursors. Equal initial concentrations of both precursors generated nanoalloys with a crystalline core-shell dense morphology, while precursor concentrations corresponding to initial equal rates of decomposition generated polycrystalline nanoalloys with a diffuse morphology.

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Ordered Colloidal Nanoalloys

Cited by 52 publications

References 0 publications

Directing Self‐Assembly of Nanoparticles at Water/Oil Interfaces

Directing Self‐Assembly of Nanoparticles at Water/Oil Interfaces

Synthesis, structure and properties of metal nanoclusters

FeCo nanoalloy formation by decomposition of their carbonyl precursors

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