Synthesis of Eu+3 doped ZnS nanoparticles by a wet chemical route and its characterization

•Cubic ZnS:Eu nanoparticles were synthesized.•PL emission as a function of excitation energy and Eu+3 concentrations was studied.•Eu doping caused an increase in the cell volume and a red shift in optical band gap.•Emission lines of electronic transitions between 5D0 and 7Fj(j=1–4) multiplets of Eu+3 observed. ZnS:Eu nanocrystals were synthesized through an aqueous chemical route using triethanolamine as complexing agent. The powder samples have been characterized systematically using a number of characterization techniques such as X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), high-resolution transmission electron microscopy (HRTEM), Raman spectroscopy, UV–Vis diffuse reflectance (DR), and photoluminescence spectroscopy. The formation of ultrafine and spherical nanoparticles with size less than 5nm was confirmed by XRD and HRTEM analysis. The band gap of ZnS:Eu was slightly red shifted with increasing the concentration of Eu+3 dopant ions. While red PL emissions were observed due to intra-4f transitions of Eu+3 ions under excitation with 374nm laser, no characteristic red emission related to 5D0–7Fj (j=0,1,2,3,4) transition of Eu+3 was observed when excited with a wavelength of 325nm.