Preparation of PbS nano‐microcrystals with different morphologies and their optical properties

PbS nano-microcrystals were prepared from Pb(OAc)2·3H2O and sulfur in a solution without any surfactant using the solvothermal process. Different morphologies, mainly including polyhedron microcrystals and sphere-like assemblies, were characterized using a scanning electron microscope (SEM) and a transmission electron microscope (TEM). PbS nano-microcrystals with cubic crystal structure were detected using X-ray diffraction (XRD), electron diffraction (ED) and high resolution transmission electron micrograph (HRTEM) techniques. The optical properties were investigated by ultraviolet-visible (UV-vis) spectroscopy, and photoluminescence spectroscopy (PL). The UV-vis absorption peaks of PbS exhibited a large blue-shift and the PL spectra had a strong and broad emission bands centered at 408 nm. The crystal growth mechanism of PbS was also discussed.