In situ liquid cell TEM and SEM observation of the CdS-graphene oxide nanocomposite

It is important to understand the dynamic behavior of 2D-composite material in liquid environment, which is helpful for designing and developing future materials. This paper reports the first direct observation of the dynamic behavior of graphene oxide (GO) and CdS nanoclusters in aqueous solution by both in situ liquid cell transmission electron microscope (LC-TEM) and in situ liquid cell scanning electron microscope (LC-SEM). It is observed that CdS prefer to attach to folds of GO. Overall, the CdS-GO attachments in composite structures are relatively stable and does not show any separation behavior in the liquid. Electron beam irradiation can cause corrosive ion generations and leads to the dissolution of CdS in the liquid, while, in some places, the CdS clusters do not dissolve, but grow slowly in the irradiated region. The overall trend, as observed with both LC-TEM and LC-SEM, agrees with the Ostwald ripening mechanism. These results can provide a deeper understanding for the development of advanced 2D-composite structures.