Abstract：
The oriented attachment (OA) of nanoparticles (NPs) is an important crystal growth mechanism in many materials. However, a comprehensive understanding of the atomic-scale alignment and attachment processes is still lacking. We conducted in situ atomic resolution studies using high-resolution transmission electron microscopy to reveal how two Pt NPs coalesce into a single particle via OA, which involves the formation of atomic-scale links and a grain boundary (GB) between the NPs, as well as GB migration. Density functional theory calculations showed that the system energy changes as a function of the number of disconnections during the coalescence process. Additionally, the formation and annihilation processes of disconnection are always accompanied by the cooperative reorientation motion of atoms. These results further elucidate the growth mechanism of OA at the atomic scale, providing microscopic insights into OA dynamics and a framework for the development of processing strategies for nanocrystalline materials.
摘要：
纳米粒子（NPs）的取向附着（OA）是许多材料中重要的晶体生长机制。然而,仍然缺乏对原子尺度对准和附着过程的全面了解。我们使用高分辨率透射电子显微镜进行了原位原子分辨率研究，以揭示两个PtNP如何通过OA合并成单个颗粒，这涉及到形成原子尺度的链接和NPs之间的晶界（GB），以及GB迁移。密度泛函理论计算表明，在合并过程中，系统能量随断开次数的变化而变化。此外,断开的形成和湮灭过程总是伴随着原子的协同重新定向运动。这些结果进一步阐明了OA在原子尺度上的生长机制，提供对OA动力学的微观见解，并为开发纳米晶材料的加工策略提供框架。
