Luminescence Studies on Ba Doped With Eu and Tm Phosphors

Abstract

Di-barium magnesium silicate doped with Eu $^{2+}$ and Tm $^{3+}$ phosphors were prepared for different concentrations of Tm $^{3+}$ ions keeping the concentration of Eu $^{2+}$ as 0.5 mol%. Photoluminescence (PL) studies of prepared samples were carried out. Emission spectra exhibited optimum green color emission at 509 nm when Tm $^{3+}$ was 1.5 mol%. Emission is expected to arise due to the transition of Eu $^{2+}$ ions from any of the sublevels of 4d $^{6}$ 5f $^{1}$ to its ground state ( ${}^{8}$ S $_{7/2})$ . This sample with 1.5 mol% of Tm $^{3+}$ is taken for X-ray diffraction analysis. XRD pattern confirmed that the sample follows monoclinic structure with C 1 2/c 1 (15) space group. Scanning Electron Microscope image of the sample exhibited the uniform morphology with average particle size of 222.54 $\mu$ m . Thermoluminescence (TL) glow curves of the sample for different UV irradiation were also recorded which presented single broaden peak centered at about ${\hbox{91}} ^{\circ}$ C. Phosphorescence decay curve was indicative of presence of dual exponential decaying section with a fast decay followed by a long decaying part.