Unveiling Growth Pathways of Multiply Twinned Gold Nanoparticles by In Situ Liquid Cell Transmission Electron Microscopy.,ACS Nano

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Unveiling Growth Pathways of Multiply Twinned Gold Nanoparticles by In Situ Liquid Cell Transmission Electron Microscopy.
ACS Nano ( IF 15.8 ) Pub Date : 2020-07-27 , DOI: 10.1021/acsnano.9b10173
Xiaoming Ma _{1,

2} , Fang Lin ₃ , Xin Chen ₁ , Chuanhong Jin _{2,

4}

Affiliation

A mechanistic understanding of the growth of multiply twinned nanoparticles (MTPs), such as decahedra (Dh) and icosahedra (Ih), is crucial for precisely controlled syntheses and applications. Despite previous successes, no consensus has been reached regarding the multiple competing growth pathways for MTPs proposed thus far, in part due to the lack of information about their nucleation and growth dynamics. Here, we used decahedral and icosahedral gold nanoparticles as a model system in conjunction with in situ liquid cell transmission electron microscopy (LCTEM) to investigate the nucleation and growth dynamics of MTPs in aqueous solution; two growth pathways were successfully identified: (A) nucleation-based layer-by-layer growth from a rounded multiply twinned seed and (B) the successive twinning and growth of tetrahedra. The LCTEM results enabled us to directly and conclusively identify the growth behaviors of intermediate products. The internal strain relaxation mechanisms and growth kinetics differ for the two pathways: in pathway A, a MTP grew by the opening and closing of re-entrant grooves at the twin boundaries, which was not found in pathway B. We also analyzed different MTP growth pathways from an energetic perspective and discussed how the preferred pathway (A or B) is related to factors, such as the initial seed yield and the size- and morphology-dependent formation of MTPs. Our results contextualize the current understanding of MTP formation mechanisms and provide insightful guidance for the precisely controlled synthesis of MTPs for practical applications.

中文翻译：

通过原位液体细胞透射电子显微镜揭示成对的孪生金纳米颗粒的生长途径。

对多孪晶纳米粒子（MTP）（例如十面体（Dh）和二十面体（Ih））的生长机理的理解对于精确控制合成和应用至关重要。尽管取得了先前的成功，但到目前为止，关于MTP的多种竞争性增长途径尚未达成共识，部分原因是缺乏有关其成核和增长动态的信息。在这里，我们使用十面体和二十面体金纳米颗粒作为模型系统并与原位结合液体细胞透射电子显微镜（LCTEM）研究水溶液中MTP的成核和生长动力学；成功确定了两个生长途径：（A）圆形多重孪生种子的成核基础逐层生长，以及（B）四面体的连续孪生和生长。LCTEM结果使我们能够直接和结论性地确定中间产品的生长行为。两条途径的内部应变松弛机制和生长动力学不同：途径A中，MTP通过在孪生边界处重入凹槽的打开和闭合而生长，这在途径B中没有发现。我们还分析了不同的MTP生长从精力充沛的角度探讨各种途径，并讨论了首选途径（A或B）如何与因素相关联，例如初始种子产量以及MTP的大小和形态依赖性形成。我们的研究结果结合了对MTP形成机理的当前理解，并为实际应用中MTP的精确控制合成提供了有见地的指导。

更新日期：2020-08-25

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