Single-phased and color tunable LiSrBO3:Dy3+, Tm3+, Eu3+ phosphors for white-light-emitting application

Novel single-phased white-light-emitting and color tunable LiSrBO3:Dy3+, Tm3+, Eu3+ phosphors were synthesized by solid-state reaction method. Their crystal structures were refined by the Rietveld method using Fullprof suite program on the basis of powder diffraction data. And their luminescent properties were characterized mainly by ultraviolet (UV) visible photoluminescence excitation (PLE), photoluminescence (PL), and Decay lifetime. The energy transfer among activators in the LiSrBO3 host has been investigated. The chromaticity diagram shows that the Dy3+, Tm3+ co-doped LiSrBO3 phosphors could emit white light and the color was tunable from cold white to warm white by Eu3+ co-activated. The excitation spectra indicate that these phosphors can be effectively excited by ultraviolet 350-400 nm, matching well with the dominant emission band of a light-emitting-diode (LED) chip. Rare-earth activators were determined to be completely dissolved into the host lattice and occupied the 4e sites deviated from an inversion center by virtue of XRD, structure refinement and photoluminescence features. Concentration quenching of phosphors LSBO: Na+ Tm3+ occurs at the doping concentration x=0.03. According to their decay curves, the calculated lifetime of LSBO:0.005Dy(3+), 0.005Tm(3+), LSBO:0.01Dy(3+), 0.005Tm(3+), and LSBO:0.015Dy(3+), 0.005Tm(3+) phosphors are 0.99 ms, 0.986 ms, and 0.96 ms, respectively. The present work suggests that these novel phosphors may have potential applications for white LEDs. (C) 2017 Elsevier B.V. All rights reserved.