van den Bos Karel H W, De Backer Annick, Martinez Gerardo T, Winckelmans Naomi, Bals Sara, Nellist Peter D, Van Aert Sandra
EMAT, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium.
Department of Materials, University of Oxford, 16 Parks Road, Oxford OX1 3PH, United Kingdom.
Phys Rev Lett. 2016 Jun 17;116(24):246101. doi: 10.1103/PhysRevLett.116.246101.
The development of new nanocrystals with outstanding physicochemical properties requires a full three-dimensional (3D) characterization at the atomic scale. For homogeneous nanocrystals, counting the number of atoms in each atomic column from high angle annular dark field scanning transmission electron microscopy images has been shown to be a successful technique to get access to this 3D information. However, technologically important nanostructures often consist of more than one chemical element. In order to extend atom counting to heterogeneous materials, a new atomic lensing model is presented. This model takes dynamical electron diffraction into account and opens up new possibilities for unraveling the 3D composition at the atomic scale. Here, the method is applied to determine the 3D structure of Au@Ag core-shell nanorods, but it is applicable to a wide range of heterogeneous complex nanostructures.
开发具有优异物理化学性质的新型纳米晶体需要在原子尺度上进行全面的三维（3D）表征。对于均匀的纳米晶体，从高角度环形暗场扫描透射电子显微镜图像中计算每个原子列中的原子数已被证明是获取此3D信息的成功技术。然而，具有重要技术意义的纳米结构通常由不止一种化学元素组成。为了将原子计数扩展到异质材料，提出了一种新的原子透镜模型。该模型考虑了动态电子衍射，并为在原子尺度上揭示3D组成开辟了新的可能性。在此，该方法被应用于确定Au@Ag核壳纳米棒的3D结构，但它适用于广泛的异质复杂纳米结构。
