Large-scale and shape-controlled syntheses of three-dimensional CdS nanocrystals with flowerlike structure

Large-scale three-dimensional (3D) US nanocrystals with a flowerlike morphology were synthesized by a facile hydrothermal treatment from Cd(NO3)(2), thiourea, and hexamethylenetetramine [(CH2)(6)N-4, HMT], where HMT acted as a capping agent. The reaction conditions influencing the synthesis of these 3D US nanocrystals such as initial precursor ratios, reaction time, reaction temperatures, and capping agents were studied and optimized. The morphology, structure, and phase composition of US nanostructures were examined by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), and high-resolution TEM. The formation mechanism of the 3D US nanocrystals with flowerlike structure was proposed based on the results, which may pave the way to shape-controlled synthesis of inorganic nanocrystals with 3D complex structures. The room-temperature. photoluminescence (PL) of the obtained US nanocrystals was also studied.