Li Guanxing, Xu Ming, Tang Wen-Qi, Liu Ying, Chen Cailing, Zhang Daliang, Liu Lingmei, Ning Shoucong, Zhang Hui, Gu Zhi-Yuan, Lai Zhiping, Muller David A, Han Yu
Advanced Membranes and Porous Materials Center, Physical Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia.
Jiangsu Key Laboratory of Biofunctional Materials, Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, Jiangsu Key Laboratory of New Power Batteries, College of Chemistry and Materials Science, Nanjing Normal University, Nanjing, China.
Nat Commun. 2025 Jan 22;16(1):914. doi: 10.1038/s41467-025-56215-z.
Electron ptychography, recognized as an ideal technique for low-dose imaging, consistently achieves deep sub-angstrom resolution at electron doses of several thousand electrons per square angstrom (e/Å) or higher. Despite its proven efficacy, the application of electron ptychography at even lower doses-necessary for materials highly sensitive to electron beams-raises questions regarding its feasibility and the attainable resolution under such stringent conditions. Herein, we demonstrate the implementation of near-atomic-resolution ( ~ 2 Å) electron ptychography reconstruction at electron doses as low as ~100 e/Å, for metal-organic frameworks (MOFs), which are known for their extreme sensitivity. The reconstructed images clearly resolve organic linkers, metal clusters, and even atomic columns within these clusters, while unravelling various local structural features in MOFs, including missing linkers, extra clusters, and surface termination modes. By combining the findings from simulations and experiments, we have identified that employing a small convergence semi-angle during data acquisition is crucial for effective iterative ptychographic reconstruction under such low-dose conditions. This important insight advances our understanding of the rapidly evolving electron ptychography technique and provides a novel approach to high-resolution imaging of various sensitive materials.
电子叠层成像被认为是低剂量成像的理想技术，在每平方埃几千个电子（e/Å）或更高的电子剂量下，始终能实现深度亚埃分辨率。尽管其有效性已得到证实，但对于对电子束高度敏感的材料而言，在更低剂量下应用电子叠层成像，会引发关于其可行性以及在如此严苛条件下可达到的分辨率的问题。在此，我们展示了针对金属有机框架（MOF）在低至约100 e/Å的电子剂量下实现近原子分辨率（约2 Å）的电子叠层成像重建，金属有机框架以其极高的敏感性而闻名。重建图像清晰地分辨出这些框架中的有机连接体、金属簇，甚至簇内的原子列，同时揭示了金属有机框架中的各种局部结构特征，包括缺失的连接体、额外的簇以及表面终止模式。通过结合模拟和实验结果，我们确定在数据采集期间采用小的会聚半角对于在这种低剂量条件下进行有效的迭代叠层成像重建至关重要。这一重要见解推进了我们对快速发展的电子叠层成像技术的理解，并为各种敏感材料的高分辨率成像提供了一种新方法。
