Synthesis and Luminescent Properties of Li-doped ZnS Nanostructures by Chemical Precipitation Method

Abstract

Nanocrystalline samples of ZnS and Zn1−xLixS (x = 0.005–0.07) were synthesized by chemical precipitation method without any surface‐modifying agents and characterized by using X‐ray diffraction (XRD) and photoluminescence (PL) spectra. All the prepared ZnS nanostructures acquire cubic sphalerite crystal structure with lattice constant a = 5.3534±0.011 Å. The concentration of doping ions has little effect on the intensity of the doped ZnS nanoparticles in the XRD peaks. The PL spectra recorded for undoped ZnS nanocrystals at room temperature exhibit one strong emission peak at 425 nm (Ex = 374 nm). In case of doped samples excitation as well as emission peaks in the corresponding PL spectra are blue shifted which is attributed to S2− anion vacancy. Photoluminescence intensity changes dramatically when doped with different Li concentrations and it reveals that the surface states greatly influence the emission from the nanostructures.