Banerjee Pritam, Roy Chiranjit, De Subhra Kanti, Santos Antonio J, Morales Francisco M, Bhattacharyya Somnath
Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai 600036, India.
IMEYMAT: Institute of Research on Electron Microscopy and Materials, University of Cádiz, Cádiz, Spain; Department of Materials Science and Metallurgic Engineering, and Inorganic Chemistry, Faculty of Sciences, University of Cádiz, Puerto Real, 11510Cádiz, Spain.
Ultramicroscopy. 2021 Feb;221:113177. doi: 10.1016/j.ultramic.2020.113177. Epub 2020 Nov 23.
Nanoparticles have a wide range of applications due to their unique geometry and arrangement of atoms. For a precise structure-property correlation, information regarding atomically resolved 3D structures of nanoparticles is utmost beneficial. Though modern aberration-corrected transmission electron microscopes can resolve atoms with the sub-angstrom resolution, an atomic-scale 3D reconstruction of a nanoparticle using Scanning Transmission Electron Microscopy (STEM) based tomographic method faces hurdles due to high electron irradiation damage and "missing-wedge". Instead, inline 3D holography based tomographic reconstructions from single projection registered at low electron doses is more suitable for defining atomic positions at nanostructures. Nanoparticles are generally supported on amorphous carbon film for Transmission Electron Microscopy (TEM) experiments. However, neglecting the influence of carbon film on the tomographic reconstruction of the nanoparticle may lead to ambiguity. To address this issue, the effect of amorphous carbon support was quantitatively studied using simulations and experiments and it was revealed that increasing thickness and/or density of carbon support increases distortion in tomograms.
由于其独特的几何形状和原子排列，纳米颗粒有着广泛的应用。为了实现精确的结构-性能关联，有关纳米颗粒原子分辨三维结构的信息极为有用。尽管现代像差校正透射电子显微镜能够以亚埃分辨率分辨原子，但使用基于扫描透射电子显微镜（STEM）的断层扫描方法对纳米颗粒进行原子尺度的三维重建面临着高电子辐照损伤和“缺失楔形”等障碍。相反，基于低剂量电子下单个投影的在线三维全息断层扫描重建更适合于确定纳米结构中的原子位置。在透射电子显微镜（TEM）实验中，纳米颗粒通常支撑在非晶碳膜上。然而，忽略碳膜对纳米颗粒断层扫描重建的影响可能会导致歧义。为了解决这个问题，通过模拟和实验定量研究了非晶碳支撑的影响，结果表明增加碳支撑的厚度和/或密度会增加断层图像中的畸变。
