Structural and photoluminescence properties of Eu-doped ZnS nanoparticles

Pure and Eu-doped ZnS nanoparticles have been synthesized by chemical precipitation technique. Morphological study reveals the spherical nature of the synthesized nanoparticles as well as its average size to be 29-37 nm. The effect of Eu-doping on structural and optical properties of the synthesized nanoparticles has been investigated. Energy dispersive X-ray spectroscopy confirms the stoichiometry of the synthesized nanoparticles. X-ray diffraction study reveals that the synthesized nanoparticles possess the cubic crystal structure. XRD confirms that higher doping concentration of Eu from 10 to 20% results in the formation of Eu2O3. UV-visible spectroscopy reveals that the band gap of the pure ZnS nanoparticles is 4.2 eV, which further decreases with addition of Eu, to 3.9 eV. Fourier transforms Infra-red spectroscopy shows the presence of surface passivating agent, mercaptoethanol, oil the surface of the synthesized nanoparticles. Photoluminescence spectrum for pure ZnS nanoparticles has been found to be broad and asymmetric, whereas sharp peaks are observed when it was doped with Eu. There are five strong emission peaks at 574, 591, 617, 700, 754 nm have been observed in the PL spectra of the Eu-doped ZnS nanoparticles, respectively associated with (D0 -> F6)-D-5-F-7, E-7(4), F-7(2), F-7(1), F-7(0) transitions. The possible mechanism of observed structural and photoluminescence has been explained on the basis of Eu-doping. (C) 2013 Elsevier Ltd. All rights reserved.