低维金属纳米结构的无损伤原子成像与定量电子显微分析

Metallic nanostructures including nanoparticles and nanowires have wide application in many fields such as catalysis and energy. Direct observation and understanding of their atomic structures is of vital importance for building up structure-property relationship. Aberration-corrected electron microscopy has been approved to be a powerful tool for characterizing the atomic structure of nanomaterials, however, the atomic information is still difficult to obtain for either ultra-small particles and ultrathin nanowires or nanomaterials with complicated structure and composition distribution. In this proposal, on the basis of aberration-correction, we will develop low dose techniques that could provide non-destructive atomic-scale imaging for ultra-small nanostructures. Meanwhile, complicated structures/compositions could be analyzed based on the application of quantitative electron microscopy. Finally, dynamic information will be obtained and connected with static atomic structures using in situ environmental electron microscopy. All these characterizations will provide a full understanding for the system of metallic nanostructures.

金属纳米颗粒、纳米线等低维纳米结构在催化、能源等领域应用广泛，观察和理解其原子结构对构建结构-性能的联系至关重要。像差校正电子显微方法是揭示纳米材料原子结构的有力工具，然而对于超小尺度的纳米颗粒、纳米线，或成分、结构复杂的纳米结构， 其原子尺度信息仍然难以获得。本课题申请旨在像差校正技术的基础上，发展低剂量无损伤成像技术并结合原位环境表征，实现对电子束敏感的小尺度金属纳米结构的原子成像，应用定量显微分析实现复杂成分分布的探测，并最终将静态原子结构与动态结构演变相联系，以期获得对金属纳米结构的全面理解。

小尺度金属纳米结构因为电子束辐照敏感特性以及尺度小的特性，使得原子尺度的微观结构表征相对困难。本项目以小尺度金属纳米结构为例，发展低剂量像差校正成像的电子显微学手段，解析样品中的原子结构，并对掺杂元素、缺陷结构等进行定量分析。在静态高分辨表征的基础上，进一步引入动态原位液体表征实验，探究金属纳米颗粒的烧结过程。最后，将发展的低剂量成像方法引用到包括锂金属以及低维卤化物钙钛矿材料在内的其他敏感材料，都取得了成功，验证了本项目发展的低剂量成像手段的有效性。

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