Peng Xinxing, Pelz Philipp M, Zhang Qiubo, Chen Peican, Cao Lingyun, Zhang Yaqian, Liao Hong-Gang, Zheng Haimei, Wang Cheng, Sun Shi-Gang, Scott Mary C
National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California, 94720, USA.
Department of Materials Science and Engineering, University of California, Berkeley, California, 94720, USA.
Nat Commun. 2022 Sep 3;13(1):5197. doi: 10.1038/s41467-022-32330-z.
Metal-organic layers (MOLs) are highly attractive for application in catalysis, separation, sensing and biomedicine, owing to their tunable framework structure. However, it is challenging to obtain comprehensive information about the formation and local structures of MOLs using standard electron microscopy methods due to serious damage under electron beam irradiation. Here, we investigate the growth processes and local structures of MOLs utilizing a combination of liquid-phase transmission electron microscopy, cryogenic electron microscopy and electron ptychography. Our results show a multistep formation process, where precursor clusters first form in solution, then they are complexed with ligands to form non-crystalline solids, followed by the arrangement of the cluster-ligand complex into crystalline sheets, with additional possible growth by the addition of clusters to surface edges. Moreover, high-resolution imaging allows us to identify missing clusters, dislocations, loop and flat surface terminations and ligand connectors in the MOLs. Our observations provide insights into controllable MOL crystal morphology, defect engineering, and surface modification, thus assisting novel MOL design and synthesis.
金属有机层（MOLs）因其可调节的框架结构，在催化、分离、传感和生物医学领域具有高度的应用吸引力。然而，由于在电子束照射下会受到严重损伤，使用标准电子显微镜方法获取有关MOLs形成和局部结构的全面信息具有挑战性。在此，我们结合液相透射电子显微镜、低温电子显微镜和电子叠层成像技术，研究了MOLs的生长过程和局部结构。我们的结果显示了一个多步骤的形成过程，其中前驱体簇首先在溶液中形成，然后它们与配体络合形成非晶态固体，接着簇-配体络合物排列成晶体片层，通过向表面边缘添加簇还可能有额外的生长。此外，高分辨率成像使我们能够识别MOLs中缺失的簇、位错、环和平面表面终止以及配体连接体。我们的观察结果为可控的MOL晶体形态、缺陷工程和表面修饰提供了见解，从而有助于新型MOL的设计和合成。
