S. Chemingui, M. Ferhi, K. Horchani-Naifer and M. Férid
universty Tunis Elmanar,
Keywords: Polyphosphate, Dysprosium Luminescence, Chromaticity, White light, Blue light
Summary:Dy3+doped lanthanum polyphosphate La(PO3)3 powder compounds have been synthesized by solid state reaction. Their characterization by X-ray diffraction, IR absorption spectroscopy and Raman scattering spectroscopy show that is crystallized in the orthorhombic system with space group C2221 and cell parameters: a= 11.295(2) Å, b =8.637 (2) Å, c = 7.387 6(4) Å, (2), Z = 4 and V= 720,594 (1) Å3. The structure of La(PO3)3 doped with 2% of Dy3+ has been resolved. It is consists of a three-dimensional framework of LaO8 octahedra, linked by (PO4)n tetrahedral units, forming tunnels running parallel to. The spectroscopic properties of the studied material have been measured by means of emission and excitation spectra, including the result of luminescence decay of Dy(III) ion. The luminescence intensities have been found to be strongly dependent on the concentration of Dy3+ ion causing to concentration quenching effect. The fluorescence decay from 4F9/2 level has been measured by monitoring the intense 4F9/2→6H13/2 transition. The decay curves have been found to be perfectly single exponential for all samples. The CIE chromaticity coordinates have been determined from emission spectra to evaluate the emitted light as function of Dy3+ concentration.