Mechanochemical synthesis of lead sulfide (PbS) nanocrystals from lead oxide

Lead sulfide (PbS) is an important nanomaterial due to its unique semiconductor properties. This paper contains the first example of the mechanochemical synthesis of PbS nanomaterials from lead oxide (PbO) and sodium sulfide (Na2S) at room temperature. Nanocrystals formed by this method have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), and high-resolution TEM (HRTEM), revealing nanocrystals with a face-centered cubic PbS structure and a uniform morphology. Average particles sizes ranging from 11.4 nm to 23.8 nm could be achieved by varying the milling speed. The optical properties of the nanocrystals were detected by UV-visible absorption spectroscopy (IJV-Vis), photoluminescence spectroscopy (PL), Fourier Transform Infrared spectrometer (FT-IR) and confirm the nanocrystals have band gaps of between 3.84 eV and 3.95 eV, representing a significant blue shift compared to naturally occurring PbS. The mechanochemically synthesized PbS nanocrystals exhibit quantum confinement effect caused by the tiny size of the nanocrystals. (C) 2019 Elsevier B.V. All rights reserved.