Ong Xuanwei, Gupta Shashank, Wu Wen-Ya, Chakrabortty Sabyasachi, Chan Yinthai
Department of Chemistry, National University of Singapore.
Materials Processing and Characterisation Department, A*STAR, Institute of Materials Research and Engineering.
J Vis Exp. 2017 Aug 10(126):56009. doi: 10.3791/56009.
Here, we describe a protocol that allows for shape-anisotropic cadmium chalcogenide nanocrystals (NCs), such as nanorods (NRs) and tetrapods (TPs), to be covalently and site-specifically linked via their end facets, resulting in polymer-like linear or branched chains. The linking procedure begins with a cation-exchange process in which the end facets of the cadmium chalcogenide NCs are first converted to silver chalcogenide. This is followed by the selective removal of ligands at their surface. This results in cadmium chalcogenide NCs with highly reactive silver chalcogenide end facets that spontaneously fuse upon contact with each other, thereby establishing an interparticle facet-to-facet attachment. Through the judicious choice of precursor concentrations, an extensive network of linked NCs can be produced. Structural characterization of the linked NCs is carried out via low- and high-resolution transmission electron microscopy (TEM), as well as energy-dispersive X-ray spectroscopy, which confirm the presence of silver chalcogenide domains between chains of cadmium chalcogenide NCs.
在此，我们描述了一种方法，该方法可使形状各向异性的硫属镉化物纳米晶体（NCs），如纳米棒（NRs）和四足体（TPs），通过其端面进行共价且位点特异性连接，从而形成类似聚合物的线性或支化链。连接过程始于阳离子交换过程，其中硫属镉化物NCs的端面首先转化为硫属银化物。接下来是选择性去除其表面的配体。这就产生了具有高反应活性硫属银化物端面的硫属镉化物NCs，它们在相互接触时会自发融合，从而建立颗粒间的面对面连接。通过明智地选择前驱体浓度，可以产生广泛的连接NCs网络。通过低分辨率和高分辨率透射电子显微镜（TEM）以及能量色散X射线光谱对连接的NCs进行结构表征，这些表征证实了在硫属镉化物NCs链之间存在硫属银化物域。
