发表机构
Stanford University; Stanford University School of Medicine（斯坦福大学; 斯坦福大学医学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究利用5DSTEM同时观测Au纳米晶生长中的形貌、取向与应变，揭示集合动力学源于颗粒层面的连续生长与定向附着合并，为连接合成路径与材料性质提供通用框架。
AI 中文摘要
解析集合生长动力学如何从颗粒和晶粒层面的动态中涌现，对于纳米晶合成的预测性控制至关重要。本研究通过连续采集将时间分辨的四维扫描透射电子显微镜（4DSTEM）扩展至五维（5DSTEM），用于同时解析Au纳米晶在水相HAuCl4中生长过程中的形貌、晶体取向和晶格应变。尽管集合生长遵循表面反应限制动力学，但单个纳米颗粒表现出不同的路径，包括连续生长和通过定向附着实现的离散合并。这些路径展现出特征性的取向动力学：连续生长期间取向稳定或逐渐选择，而合并期间则发生突然重构后随之对齐。在集合层面，面外取向分布在早期即建立并保持稳定，而面内取向则保持广泛分布，无全局对齐。拉伸应变从颗粒表面和界面逐步发展，直接将晶格畸变与演化的形貌和晶体结构相关联。通过将集合动力学与颗粒和晶粒分辨的结构演化相连接，5DSTEM为揭示功能纳米材料中的异质生长机制以及将合成路径与结构依赖性性质相关联提供了一个通用框架。
英文摘要
Resolving how ensemble growth kinetics emerge from particle- and grain-level dynamics is essential for predictive control of nanocrystal synthesis. Here, time-resolved four-dimensional scanning transmission electron microscopy (4DSTEM), extended into five dimensions (5DSTEM) through continuous acquisition, is used to simultaneously resolve morphology, crystallographic orientation, and lattice strain during Au nanocrystal growth in aqueous HAuCl4. Although ensemble growth follows surface-reaction-limited kinetics, individual nanoparticles exhibit distinct pathways, including continuous growth and discrete coalescence through oriented attachment. These pathways display characteristic orientation dynamics, with stable or gradually selected orientations during continuous growth and abrupt reconfiguration followed by alignment during coalescence. At the ensemble level, the out-of-plane orientation distribution is established early and remains stable, whereas in-plane orientations remain broadly distributed without global alignment. Tensile strain develops progressively from particle surfaces and interfaces, directly linking lattice distortion with evolving morphology and crystallographic structure. By connecting ensemble kinetics with particle- and grain-resolved structural evolution, 5DSTEM provides a general framework for uncovering heterogeneous growth mechanisms and for relating synthesis pathways to structure-dependent properties in functional nanomaterials.
