Flowerlike PbS Microcrystals: Citric Acid Assisted Synthesis, Shape Evolution, and Electrical Conductivities

Lead sulfide (PbS) with various morphologies including flowerlike, microsphere, multipod, six-armed star, and truncated octahedron has been synthesized selectively under hydrothermal conditions. The synthesis procedure variables such as concentration of the citric acid (CA), kinds of surfactant, reaction temperature, and reaction time were observed to influence the resultant shape of PbS microstructures. The structure and morphology of the obtained products were characterized by means of X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), and Fourier transform infrared spectroscopy (FTIR) analysis. On the basis of the time-dependent experimental data, the possible formation mechanism related to facet-selective growth and dissolution-recrystallization was presented. Furthermore, the electrical conductivities for different morphologies of PbS were measured to investigate the possible effect of morphology on the electrical conductivity.