Publication
Title
A novel red $Ca_{8.5}Pb_{0.5}Eu(PO_{4})_{7}$ phosphor for light emitting diodes application
Author
Abstract
 Ca9-xPbxEu(PO4)(7) (0 <= x <= 1) solid solutions with a whitlockite-type (or beta-Ca-3(PO4)(2)-type) structure (sp.gr. R3c) were prepared by a standard solid-state method in air. Their luminescent properties under near-ultraviolet (n-UV) light were investigated. Excitation spectra of Ca9-xPbxEu(PO4)(7) showed the strongest absorption at about 395 nm, which matches well with commercially available n-UV-emitting GaN-based LED chips. Emission spectra indicated an intense red emission due to the D-5(0) -> F-7(2) transition of Eu3+, with a maximum in the intensity for Ca8.5Pb0.5Eu(PO4)(7). The emission intensity of Ca8.5Pb0.5Eu(PO4)(7) was about 1.8 times higher than that of a Ca9Eu(PO4)(7) phosphor. We suggest that the introduction of Pb2+ is an efficient approach to enhance luminescence properties of such phosphors. We clarified the influence of the Ca2+/Pb2+ substitution on intensities of three bands for the D-5(0) -> F-7(0) transition in excitation spectra of Ca9-xPbxEu(PO4)(7). In addition, we found a reversible first-order phase transition from R3c to R (3) over barc symmetry by second-harmonic generation in the range from 753 K (x = 1) to 846 K (x = 0). (C) 2015 Elsevier B.V. All rights reserved.
Language
English
Source (journal)
Journal of alloys and compounds. - Amsterdam
Publication
Amsterdam : 2015
ISSN
0925-8388
Volume/pages
647(2015), p. 965-972
ISI
000361156400135
Full text (Publisher's DOI)
Full text (publisher's version - intranet only)
UAntwerpen
 Faculty/Department Research group [E?say:metaLocaldata.cgzprojectinf] Optimising the photoluminescence in scheelite-based materials through the incommensurate modulation of the cations. Publication type Subject Affiliation Publications with a UAntwerp address