Preparation and photoluminescent properties of doped nanoparticles of ZnS by solid-state reaction

Nanometer-sized Eu3+-doped ZnS and Mn2+-doped ZnS particles were prepared by solid-state method at low temperature. The structures and properties of those materials were characterized by X-ray diffraction (XRD) and photoluminescent spectroscopy techniques. The XRD patterns reveal that the doped ZnS nanoparticles belong to zinc-blende structure. The concentration of doping ions has little effect on the sizes of the doped ZnS nanoparticles, which mainly depends on the temperature of preparation. The emission peaks from the 5D0→7FJ (J=1, 2, and 4) electronic energy transitions of Eu3+ were observed in the emission spectra of the ZnS:Eu3+ nanoparticles. The intensity ratio of the two peaks from the 5D0→7F1 and 5D0→7F2 transitions indicates that more Eu3+ ions occupy the sites with no inversion symmetry. For the ZnS:Mn2+ nanoparticles, an orange emission from the 4T1→6A1 transition of Mn2+ is present, indicating that the doping ions occupy the positions of the ZnS lattices. Meanwhile, UV-induced luminescence enhancement was observed for the ZnS:Mn2+ nanoparticles, the possible reason of which is discussed primarily.