Albrecht Wiebke, van de Glind Arjen, Yoshida Hideto, Isozaki Yusuke, Imhof Arnout, van Blaaderen Alfons, de Jongh Petra E, de Jong Krijn P, Zečević Jovana, Takeda Seiji
Soft Condensed Matter, Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 5, Utrecht 3584 CC, The Netherlands.
Inorganic Chemistry and Catalysis, Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, Utrecht 3584 CG, The Netherlands.
Ultramicroscopy. 2018 Oct;193:97-103. doi: 10.1016/j.ultramic.2018.05.006. Epub 2018 Jun 18.
In-situ transmission electron microscopy experiments are of great interest to nanoscience and nanotechnology. However, it is known that the electron beam can have a significant impact on the structure of the sample which makes it important to carefully interpret in-situ data. In this work, we studied the thermal stability of CTAB-stabilized gold nanorods under different gaseous environments in an environmental transmission electron microscope and compared the outcome to ex-situ heating experiments. We observed a remarkable influence of the electron beam: While the nanorods were stable under inert conditions when exposed to the electron beam even at 400°C, the same nanorods reshaped at temperatures as low as 100°C under ex-situ conditions. We ascribe the stabilizing effect to the transformation of the CTAB bi-layer into a thin carbon layer under electron beam irradiation, preventing the nanorods from deforming. When exposed to an oxidizing environment in the environmental transmission electron microscope, this carbon layer was gradually removed and the gold atoms became mobile allowing for the deformation of the rod. This work highlights the importance of understanding the phenomena taking place under electron beam irradiation, which can greatly affect in-situ experiments and conclusions drawn from these. It stresses that in-situ electron microscopy data, taken on measuring the temperature dependence of nanoparticle properties, should be carefully assessed and accompanied by ex-situ experiments if possible.
原位透射电子显微镜实验在纳米科学和纳米技术领域备受关注。然而，众所周知，电子束会对样品结构产生重大影响，这使得仔细解读原位数据变得至关重要。在这项工作中，我们在环境透射电子显微镜中研究了不同气体环境下十六烷基三甲基溴化铵（CTAB）稳定的金纳米棒的热稳定性，并将结果与非原位加热实验进行了比较。我们观察到电子束有显著影响：虽然纳米棒在惰性条件下即使暴露于400°C的电子束下仍保持稳定，但在非原位条件下，相同的纳米棒在低至100°C的温度下就会发生重塑。我们将这种稳定作用归因于在电子束辐照下CTAB双层转变为薄碳层，从而防止纳米棒变形。当在环境透射电子显微镜中暴露于氧化环境时，该碳层会逐渐被去除，金原子变得可移动，从而使纳米棒发生变形。这项工作突出了理解电子束辐照下发生的现象的重要性，这些现象会极大地影响原位实验及其得出的结论。它强调，在测量纳米颗粒性质的温度依赖性时所获取的原位电子显微镜数据，应仔细评估，如有可能应辅以非原位实验。
