Analysis & Testing Center, Beijing Institute of Technology, Beijing 102488, China.
School of Environmental and Safety Engineering, North University of China, Taiyuan 030051, China.
Molecules. 2022 Jul 30;27(15):4877. doi: 10.3390/molecules27154877.
Revealing the evolutional pathway of the nucleation and crystallization of nanostructures at the atomic scale is crucial for understanding the complex growth mechanisms at the early stage of new substances and spices. Real-time discrimination of the atomic mechanism of a nanodroplet transition is still a formidable challenge. Here, taking advantage of the high temporal and spatial resolution of transmission electron microscopy, the detailed growth pathway of Pb nanodroplets at the early stage of nucleation was directly observed by employing electron beams to induce the nucleation, growth, and fusion process of Pb nanodroplets based on PbTiO nanowires. Before the nucleation of Pb nanoparticles, the atoms began to precipitate when they were irradiated by electrons, forming a local crystal structure, and then rapidly and completely crystallized. Small nanodroplets maintain high activity and high density and gradually grow and merge into stable crystals. The whole process was recorded and imaged by HRTEM in real time. The growth of Pb nanodroplets advanced through the classical path and instantaneous droplet coalescence. These results provide an atomic-scale insight on the dynamic process of solid/solid interface, which has implications in thin-film growth and advanced nanomanufacturing.
揭示纳米结构成核和结晶的原子尺度演化途径对于理解新物质和香料早期复杂的生长机制至关重要。实时区分纳米液滴转变的原子机制仍然是一个巨大的挑战。在这里，利用透射电子显微镜的高时空分辨率，通过电子束诱导基于 PbTiO 纳米线的 Pb 纳米液滴的成核、生长和融合过程，直接观察 Pb 纳米液滴在成核早期的详细生长途径。在 Pb 纳米颗粒成核之前，原子在被电子照射时开始沉淀，形成局部晶体结构，然后迅速完全结晶。小液滴保持高活性和高密度，并逐渐生长和合并成稳定的晶体。整个过程通过高分辨透射电子显微镜实时记录和成像。Pb 纳米液滴的生长通过经典途径和瞬时液滴聚结推进。这些结果为固/固界面的动态过程提供了原子尺度的见解，这对薄膜生长和先进的纳米制造具有重要意义。
