Crystallography of sensitive materials High-resolution transmission electron microscopy is an invaluable tool for looking at the crystalline structures of many materials. However, the need for high beam doses, especially as a sample is rotated to find the crystal axes, can lead to damage, particularly in fragile materials. Zhang et al. combined a state-of-the-art direct-detection electron-counting camera with ways to limit the overall electron dose to analyze delicate materials such as metal organic frameworks. With this approach, they could see the benzene rings in a UiO-66 linker and the coexistence of ligand-free (metal-exposing) and ligand-capped surfaces in UiO-66 crystals. Science, this issue p. 675 A direct-detection camera allows for high-resolution transmission electron microscopy imaging of beam-sensitive materials. High-resolution imaging of electron beam–sensitive materials is one of the most difficult applications of transmission electron microscopy (TEM). The challenges are manifold, including the acquisition of images with extremely low beam doses, the time-constrained search for crystal zone axes, the precise image alignment, and the accurate determination of the defocus value. We develop a suite of methods to fulfill these requirements and acquire atomic-resolution TEM images of several metal organic frameworks that are generally recognized as highly sensitive to electron beams. The high image resolution allows us to identify individual metal atomic columns, various types of surface termination, and benzene rings in the organic linkers. We also apply our methods to other electron beam–sensitive materials, including the organic-inorganic hybrid perovskite CH3NH3PbBr3.

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电子束敏感晶体材料的原子分辨率透射电子显微镜

敏感材料的晶体学 高分辨率透射电子显微镜是查看许多材料晶体结构的宝贵工具。然而，需要高光束剂量，尤其是在旋转样品以找到晶轴时，可能会导致损坏，尤其是在易碎材料中。张等人。将最先进的直接检测电子计数相机与限制整体电子剂量的方法相结合，以分析金属有机框架等精密材料。通过这种方法，他们可以看到 UiO-66 接头中的苯环以及 UiO-66 晶体中无配体（暴露金属）和配体封端的表面的共存。科学，这个问题 p。675 直接检测相机允许对光束敏感材料进行高分辨率透射电子显微镜成像。电子束敏感材料的高分辨率成像是透射电子显微镜 (TEM) 中最困难的应用之一。挑战是多方面的，包括以极低的光束剂量获取图像、晶体区域轴的时间受限搜索、精确的图像对准以及散焦值的准确确定。我们开发了一套方法来满足这些要求，并获取通常被认为对电子束高度敏感的几种金属有机框架的原子分辨率 TEM 图像。高图像分辨率使我们能够识别单个金属原子柱、各种类型的表面终止和有机连接器中的苯环。我们还将我们的方法应用于其他电子束敏感材料，