Liquid Cell Transmission Electron Microscopy Study of Platinum Iron Nanocrystal Growth and Shape Evolution

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• 作者：Hong-Gang Liao ; Haimei Zheng
• 刊名：The Journal of the American Chemical Society
• 出版年：2013
• 出版时间：April 3, 2013
• 年：2013
• 卷：135
• 期：13
• 页码：5038-5043
• 全文大小：406K
• 年卷期：v.135,no.13(April 3, 2013)
• ISSN：1520-5126

文摘

We study solution growth of platinum iron nanocrystals in situ in a liquid cell by using transmission electron microscopy. By varying the oleylamine concentration, we observed that platinum iron nanoparticle growth follows different trajectories with diverse shape evolution. With 20% oleylamine, three stages of growth were observed: (i) nucleation and growth of platinum iron nanoparticles in the precursor solution; (ii) nanowire formation by shape-directed nanoparticle attachment; and (iii) breakdown or shrinkage of the nanowires into individual nanoparticles with large size distribution. With 30% oleylamine, formation of platinum iron nanowires similar to that with 20% oleylamine was observed. However, those nanowires do not break down or shrink, which suggests that nanowires are stabilized by oleylamine as surfactant binding on the surface. With 50% oleylamine, after the individual nanoparticles are formed, they do not merge into nanowires. The shape of the nanoparticle is strongly influenced by the neighboring nanoparticles due to stereo-hindrance effects. Real-time observation of the dynamic growth process sheds light on the controllable synthesis of nanomaterials.