Shape-controlled syntheses of PbS submicro-/nano-crystals via hydrothermal method

Large-scale PbS crystals in sub-micrometer/nanometer dimensions with various morphologies, such as cubes, dendrites, stars, and wires, were synthesized via a facile hydrothermal method. Pb(NO3)2, thiourea, and capping agents like hexamethylenetetramine (HMT) and cetyltrimethylammonium bromide (CTAB), were used as precursors for the syntheses. The morphology, structure, and phase composition of PbS submicro-/nano-structures were determined by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and transmission electron microscopy (TEM). The influence of different capping agents on the growth of these PbS crystals was investigated and optimized. The formation mechanisms of these PbS crystals were proposed, which could give a proper explanation on the evolution of the crystal growth and may also pave the way to shape-controlled synthesis of other inorganic crystals with versatile complex structures via this facile hydrothermal method.