Verma Ekta, Choi Myung-Hoon, Kar Nabojit, Baker Lane A, Skrabalak Sara E
Department of Chemistry, Indiana University - Bloomington, Bloomington, Indiana, 47405, USA.
Department of Chemistry, Texas A&M University, College Station, Texas, 77843, USA.
Nanoscale. 2024 Apr 25;16(16):8002-8012. doi: 10.1039/d4nr00202d.
Metal nanocrystals (NCs) produced by colloidal synthesis have a variety of structural features, such as different planes, edges, and defects. Even from the best colloidal syntheses, these characteristics are distributed differently in each NC. This inherent heterogeneity can play a significant role in the properties displayed by NCs. This manuscript reports the use of electrochemistry to synthesize Au NCs in a system evaluated to track individual NC growth trajectories as a first step toward rapid identification of NCs with different structural features. Au nanocubes were prepared colloidally and deposited onto a glassy carbon electrode using either electrospray or an airbrush, resulting in well-spaced Au nanocubes. The Au nanocubes then served as seeds as gold salt was reduced to deposit metal at constant potential. Deposition at constant potential facilitates overgrowth on the Au nanocubes to achieve new NC shapes. The effects of applied potential, deposition time, precursor concentration, and capping agents on NC shape evolution were studied. The outcomes are correlated to results from traditional colloidal syntheses, providing a bridge between the two synthetic strategies. Moreover, scanning electron microscopy was used to image the same NCs before and after deposition, linking individual seed features to differences in deposition. This ability is anticipated to enable tracking of individual growth trajectories of NCs to elucidate sources of heterogeneity in NC syntheses.
通过胶体合成制备的金属纳米晶体（NCs）具有多种结构特征，例如不同的晶面、边缘和缺陷。即使是最佳的胶体合成方法，这些特征在每个NC中的分布也不尽相同。这种固有的异质性会对NCs所表现出的性质产生重大影响。本论文报道了利用电化学方法在一个经过评估的体系中合成金纳米晶体，以此追踪单个NC的生长轨迹，作为快速识别具有不同结构特征的NCs的第一步。金纳米立方体通过胶体法制备，并使用电喷雾或喷枪沉积在玻碳电极上，从而得到间距良好的金纳米立方体。然后，金纳米立方体作为种子，在恒定电位下将金盐还原以沉积金属。恒定电位沉积有助于在金纳米立方体上进行过度生长，从而获得新的NC形状。研究了施加电位、沉积时间、前驱体浓度和封端剂对NC形状演变的影响。这些结果与传统胶体合成的结果相关联，在两种合成策略之间架起了一座桥梁。此外，利用扫描电子显微镜对沉积前后的相同NCs进行成像，将单个种子特征与沉积差异联系起来。预计这种能力能够追踪NCs的个体生长轨迹，以阐明NC合成中异质性的来源。
