Controlled Synthesis of Pyramid-Aggregated Sphere-like Cadmium Sulfide in the Presence of a Polymer

Large-scale three-dimensional cadmium sulfide (CdS) spheres composed of hexagon-based pyramids were synthesized through a facile solution-phase reaction from CdCl₂, thioacetamide, and a polymer, where the polymer acted as both a dispersant and coating agent. The reaction conditions influencing the synthesis of these three-dimensional (3D) CdS nanostructures such as reaction temperature, reaction time, the concentration of the polymer, and the kinds of precursors used were investigated. The phase composition, the morphology, and the structure of CdS nanostructures were examined by X-ray diffraction, X-ray photoelectron spectra, field emission scanning electron microscopy, transmission electron microscopy, and high-resolution transmission electron microscopy. The possible formation mechanism of the novel CdS spheres was proposed based on the above analysis. The room-temperature Raman spectrum and photoluminescence spectra of the obtained CdS nanocrystals were also studied.