Unravelling Kinetic and Thermodynamic Effects on the Growth of Gold Nanoplates by Liquid Transmission Electron Microscopy
Unravelling Kinetic and Thermodynamic Effects on the Growth of Gold Nanoplates by Liquid Transmission Electron Microscopy
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DOI：
10.1021/acs.nanolett.5b00140
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发表时间：
2015-04-01
期刊：
影响因子：
10.8
通讯作者：
Ricolleau, Christian
中科院分区：
文献类型：
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作者：
Alloyeau, Damien;Dachraoui, Walid;Ricolleau, Christian
胶体纳米颗粒的生长同时受到难以区分的动力学和热力学效应的驱动。我们已经利用在液体中的原位扫描透射电子显微镜研究辐射分解生长的Au纳米片，并解开影响其形成和形状的机制。电子剂量提供了生长速率的直接控制，其允许量化对平面纳米颗粒形成的动力学效应。事实上，我们证明，每单位面积的表面反应速率具有相同的剂量率依赖行为比在液体电池中的还原剂的浓度。有趣的是，我们还确定了用于纳米颗粒刻面的金单体的临界供应速率，对应于每秒三层，高于该临界供应速率，纳米片的形成是不可能的，因为生长随后由动力学效应主导。在较低的电子剂量下，生长是由热力学驱动的，纳米片的形成和形状与生长过程中形成的孪晶面直接相关。
The growth of colloidal nanoparticles is simultaneously driven by kinetic and thermodynamic effects that are difficult to distinguish. We have exploited in situ scanning transmission electron microscopy in liquid to study the growth of Au nanoplates by radiolysis and unravel the mechanisms influencing their formation and shape. The electron dose provides a straightforward control of the growth rate that allows quantifying the kinetic effects on the planar nanoparticles formation. Indeed, we demonstrate that the surface-reaction rate per unit area has the same dose-rate dependent behavior than the concentration of reducing agents in the liquid cell. Interestingly, we also determine a critical supply rate of gold monomers for nanoparticle faceting, corresponding to three layers per second, above which the formation of nanoplates is not possible because the growth is then dominated by kinetic effects. At lower electron dose, the growth is driven by thermodynamic and the formation and shape of nanoplates are directly related to the twin-planes formed during the growth.