Rational nanoparticle design is one of the main goals of materials science, but it can only be achieved via a thorough understanding of the growth process and of the respective roles of the molecular species involved. We demonstrate that a combination of complementary techniques can yield novel information with respect to their individual contributions. We monitored the growth of long aspect ratio silver rods from gold pentatwinned seeds by three in situ techniques (small-angle X-ray scattering, optical extinction spectroscopy and liquid-cell transmission electron microscopy). Exploiting the difference in reaction speed between the bulk synthesis and the nanoparticle formation in the TEM cell, we show that the anisotropic growth is thermodynamically controlled (rather than kinetically) and that ascorbic acid, widely used for its mild reductive properties, plays a shape-directing role, by stabilizing the {100} facets of the silver cubic lattice, in synergy with the halide ions. This approach can easily be applied to a wide variety of synthesis strategies.

中文翻译：

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实时原位观察揭示了抗坏血酸在银在金上各向异性生长中的双重作用。

合理的纳米颗粒设计是材料科学的主要目标之一，但是只有通过透彻了解生长过程以及所涉及分子物种的各自作用，才能实现纳米颗粒设计。我们证明，互补技术的组合可以产生关于其个人贡献的新颖信息。我们通过三种原位技术（小角度X射线散射，消光光谱和液细胞透射电子显微镜）监测了从五氧化二金种子中长宽高比银棒的生长。利用本体反应和TEM单元中纳米颗粒形成之间反应速度的差异，我们发现各向异性生长是热力学控制的（而不是动力学），而抗坏血酸 由于其柔和的还原性能而被广泛使用，通过与卤离子协同作用，通过稳定银立方晶格的{100}面，起到了形状导向的作用。这种方法可以轻松地应用于多种合成策略。