Journal ArticleDOI
Synthesis of monodisperse cobalt nanocrystals and their assembly into magnetic superlattices (invited)
Shouheng Sun,C. B. Murray +1 more
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In this paper, high temperature, solution phase reduction of cobalt chloride in the presence of stabilizing agents was employed to produce magnetic colloids (ferrofluids) of the cobalt nanocrystals.Abstract:
High temperature, solution phase reduction of cobalt chloride in the presence of stabilizing agents was employed to produce magnetic colloids (ferrofluids) of cobalt nanocrystals. We systematically synthesized and isolated nearly monodisperse nanocrystal samples ranging in size from 2 to 11 nm while maintaining better than a 7% std. dev. in diameter. As synthesized cobalt particles are each a single crystal with a complex cubic structure related to the beta phase of elemental manganese (e-Co). Annealing the nanocrystals at 300 °C converts them quantitatively to the more common hexagonal-close-packed crystal form. Deposition of these uniform cobalt particles on solid substrates by evaporation of the carrier solvent results in the spontaneous assembly of two-dimensional and three-dimensional magnetic superlattices (colloidal crystals). A combination of x-ray powder diffraction, transmission electron microscopy, and superconducting quantum interference device magnetometry were used to characterize both the d...read more
Citations
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Chemistry and properties of nanocrystals of different shapes.
TL;DR: The interest in nanoscale materials stems from the fact that new properties are acquired at this length scale and, equally important, that these properties are equally important.
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Monodisperse FePt Nanoparticles and Ferromagnetic FePt Nanocrystal Superlattices
TL;DR: Thermal annealing converts the internal particle structure from a chemically disordered face- centered cubic phase to the chemically ordered face-centered tetragonal phase and transforms the nanoparticle superlattices into ferromagnetic nanocrystal assemblies that can support high-density magnetization reversal transitions.
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Shape‐Controlled Synthesis of Metal Nanocrystals: Simple Chemistry Meets Complex Physics?
TL;DR: A comprehensive review of current research activities that center on the shape-controlled synthesis of metal nanocrystals, including a brief introduction to nucleation and growth within the context of metal Nanocrystal synthesis, followed by a discussion of the possible shapes that aMetal nanocrystal might take under different conditions.
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Synthesis and Characterization of Monodisperse Nanocrystals and Close-Packed Nanocrystal Assemblies
TL;DR: In this article, solution phase syntheses and size-selective separation methods to prepare semiconductor and metal nanocrystals, tunable in size from ∼1 to 20 nm and monodisperse to ≤ 5%, are presented.
Journal ArticleDOI
Prospects of Colloidal Nanocrystals for Electronic and Optoelectronic Applications
TL;DR: Nanocrystals (NCs) discussed in this Review are tiny crystals of metals, semiconductors, and magnetic material consisting of hundreds to a few thousand atoms each that are among the hottest research topics of the last decades.
References
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Journal ArticleDOI
Synthesis and characterization of nearly monodisperse CdE (E = sulfur, selenium, tellurium) semiconductor nanocrystallites
TL;DR: In this paper, a simple route to the production of high-quality CdE (E=S, Se, Te) semiconductor nanocrystallites is presented, based on pyrolysis of organometallic reagents by injection into a hot coordinating solvent.
Journal ArticleDOI
Light-emitting diodes made from cadmium selenide nanocrystals and a semiconducting polymer
TL;DR: In this article, a hybrid organic/inorganic electroluminescent device was constructed based on the recombination of holes injected into a layer of semiconducting p-paraphenylene vinylene (PPV) with electrons injected into the multilayer film of cadmium selenide nanocrystals.
Journal Article
Light-emitting diodes made from cadmium selenide nanocrystals and a semiconducting polymer
TL;DR: In this article, a hybrid organic/inorganic electroluminescent device was constructed based on the recombination of holes injected into a layer of semiconducting p-paraphenylene vinylene (PPV) with electrons injected into the multilayer film of cadmium selenide nanocrystals.
Journal ArticleDOI
Self-Organization of CdSe Nanocrystallites into Three-Dimensional Quantum Dot Superlattices
TL;DR: In this article, the self-organization of CdSe nanocrystallites into three-dimensional semiconductor quantum dot superlattices (colloidal crystals) is demonstrated.
Journal ArticleDOI
A silicon nanocrystals based memory
Sandip Tiwari,Farhan Rana,Hussein I. Hanafi,Allan M. Hartstein,Emmanuel F. Crabbé,Kevin K. Chan +5 more
TL;DR: In this paper, a new memory structure using threshold shifting from charge stored in nanocrystals of silicon (≊5nm in size) was described, which utilizes direct tunneling and storage of electrons in the nanocrystal.