Dong Zejian, Zhang Na, Wang Shuangbao, Liu Yuying, Zhang Lifeng, Chen Xing, Luo Langli
Institute of Molecular Plus, Department of Chemistry, Tianjin University, Tianjin 300072, P. R. China.
Key Laboratory of LCR Materials and Devices of Yunnan Province, National Center for International Research on Photoelectric and Energy Materials, School of Materials and Energy, Yunnan University, Kunming 650091, P. R. China.
J Phys Chem Lett. 2022 Aug 11;13(31):7170-7176. doi: 10.1021/acs.jpclett.2c01942. Epub 2022 Jul 29.
Atomic defects are critical to tuning the physical and chemical properties of functional materials such as catalysts, semiconductors, and 2D materials. However, direct structural characterization of atomic defects, especially their formation and annihilation under practical conditions, is challenging yet crucial to understanding the underlying mechanisms driving defect dynamics, which remain mostly elusive. Here, through atomic imaging by an aberration-corrected environmental transmission electron microscope (AC-ETEM), we directly visualize the formation and annihilation mechanism of planar defects in monoclinic WO on the atomic scale in real time. We captured the atomistic process of the nucleation dynamics of the dislocation core in the [010] direction, followed by its propagation to form a planar defect. Corroborated by density functional theory-based calculations, we rationalize the formation of dislocation through O extraction from bridge sites followed by an atomic channeling process. These observations shed light on the defect dynamics in oxides and provide atomic insights into forming and manipulating defects in functional materials.
原子缺陷对于调节催化剂、半导体和二维材料等功能材料的物理和化学性质至关重要。然而，对原子缺陷进行直接的结构表征，尤其是在实际条件下它们的形成和湮灭，具有挑战性，但对于理解驱动缺陷动力学的潜在机制至关重要，而这些机制大多仍不清楚。在这里，通过使用像差校正环境透射电子显微镜（AC-ETEM）进行原子成像，我们在原子尺度上实时直接观察到单斜WO中平面缺陷的形成和湮灭机制。我们捕捉到位错核心在[010]方向上形核动力学的原子过程，随后其扩展形成平面缺陷。基于密度泛函理论的计算证实，我们通过从桥位提取O然后进行原子沟道过程来解释位错的形成。这些观察结果揭示了氧化物中的缺陷动力学，并为功能材料中缺陷的形成和操控提供了原子层面的见解。
