How Can the Nanocrystallinity of 7 nm Spherical Co Nanoparticles Dispersed in Solution Be Improved?

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• 作者：Manon Cavalier ; Michael Walls ; Isabelle Lisiecki ; Marie-Paule Pileni
• 刊名：Langmuir
• 出版年：2011
• 出版时间：April 19, 2011
• 年：2011
• 卷：27
• 期：8
• 页码：5014-5020
• 全文大小：996K
• 年卷期：v.27,no.8(April 19, 2011)
• ISSN：1520-5827

文摘

We report a solution-phase annealing of spherical Co nanocrystals synthesized in reverse micelles and coated with dodecanoic acid. The deposition of a drop of solution on a transmission electron microscope grid shows that a progressive increase in the temperature to 316 掳C results in the progressive crystallographic transition from a polycrystalline and probably face-centered cubic Co phase to the single-crystalline hexagonal close-packed (hcp) Co phase. These nanocrystals are highly stable against oxidation and coalescence. We stress that, to our knowledge, this constitutes the first example in the literature of pure hcp-Co spherical single crystals dispersed in solution. These nanocrystals can be freely manipulated and, due to their low size dispersion, can self-organize on various substrates.