Facile One-Pot Synthesis of Metal-Semiconductor Hybrid Nanocrystals via Chemical Transformation: The Case of Cu-CuxS Heterodimers and Hetero-Oligomers

Metal-semiconductor hybrid nanocrystals (HNCs) hold great potential in the fields of photocatalysis, biomedical imaging, and anticancer nanomedicine. However, their chemical synthetic procedures remain complex and challenging. Here, we apply chemical transformation to convert metal nanostructures into metal-semiconductor HNCs following a facile one-pot polyol synthetic procedure. As case Studies, two types of Cu-CuxS HNCs, heterodimers and hetero-oligomers, are produced from Cu nanocrystals using an alkanethiol as both surfactants and the sulfur Source. This protocol utilizes Cu nanocrystals' high reactivity toward sulfidization for heterogeneous growth of copper sulfide over the remaining Cu nanocrystals. We find that Under H-2/argon, such a polyol process leads to an exclusive formation of heterodimers, while Under argon, hetero-oligomers are produced predominantly. The morphological evolution upon further chemical trails formation of both heterodimers and hetero-oligomers, including the formation of hollow nanostructures, has also been investigated. A thorough physicochemical characterization of the as-prepared HNCs is achieved through multiple transmission electron microscopy methods, combined with scanning electron microscopy, X-ray diffraction, and UV-vis spectroscopy.