Chelating ligand-mediated synthesis of hollow ZnS microspheres and its optical properties

Abstract

Monodispersed hollow ZnS microspheres have been successfully synthesized by a facile ethylenediamine tetraacetic acid (EDTA) mediated hydrothermal route. The sizes of the hollow spheres vary from 1.5 to 3.5 μm when the reaction temperature varied from 130 to 230 °C. The formation of these hollow spheres is attributed to the oriented aggregation of ZnS nanocrystals around the gas–liquid interface between H 2S and water. EDTA plays important role as chelating ligand and capping reagent, which regulates the release of Zn 2+ ions for the formation of ZnS hollow spheres. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV–vis spectroscopy, photoluminescence, and Raman spectroscopy. The obtained ZnS hollow spheres show a sharp and photostable UV emission ∼370 nm, which is attributed to the recombination process associated with interstitial sulfur vacancy.