title: Luminescence and microstructures of Eu(3+)-doped Ca9LiGd(2/3)(PO4)7.
abstract: A red-emitting phosphor, Eu(3+)-doped Ca(9)LiGd(2/3)(PO(4))(7), was synthesized by the conventional high-temperature solid-state reaction. X-ray powder diffraction (XRD) analyses confirmed the pure crystalline phase of Whitlockite-type structure. The excitation spectra of Eu(3+) doped Ca(9)LiGd(2/3)(PO(4))(7) were measured in the VUV and UV region indicating an efficient energy transfer process from the host and Gd(3+) to Eu(3+) ions. Upon excitation with VUV and UV radiation, the phosphor showed strong red emission around 611 nm corresponding to the forced electric dipole (5)D(0)→(7)F(2) transition of Eu(3+) ions. The VUV- and UV-excited luminescence spectra of Ca(9)LiGd(2/3)(PO(4))(7):Eu(3+) together with the dependence of the integrated emission intensities on the doping levels were investigated. The Eu(3+) ions were investigated by a tunable laser as an excitation source. The excitation spectra of (7)F(0)→(5)D(0) transitions suggest that there are two families of inequivalent sites for Eu(3+) in this host. The concentration quenching and crystallographic site-occupancy of Eu(3+) ions in Ca(9)LiGd(2/3)(PO(4))(7) host were discussed on the basis of the site selective excitation and emission spectra, the luminescence decay and its crystal structure.
authors.affiliation: College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, China.
authors.forename: Fuping
authors.initials: F
authors.lastname: Du
authors.forename: Rui
authors.initials: R
authors.lastname: Zhu
authors.forename: Yanlin
authors.initials: Y
authors.lastname: Huang
authors.forename: Ye
authors.initials: Y
authors.lastname: Tao
authors.forename: Hyo Jin
authors.initials: HJ
authors.lastname: Seo