Synthesis and luminescence properties of Ca5-x(PO4)3Br:xEu2+-A novel blue-emitting bromapatite phosphor for near-ultraviolet-pumped white light-emitting diodes

A series of novel Ca5-x(PO4)(3)Br:xEu(2+) (x=0.01-0.10) blue phosphors were synthesized via the conventional solid state reaction and their luminescence properties were reported. The Ca5-x(PO4)(3)Br:xEu(2+) phosphors could be excited efficiently in the wavelength range of 320-440 nm and displayed an intense asymmetric blue emission band around 458 nm under 365 nm excitation. The concentration quenching of Eu2+ in the Cas(PO4)(3)Br host was investigated in detail. The optimum doping concentration of Eu2+ was determined to be 0.07 and the energy transfer mechanism was certified to be the dipole-dipole interaction. Moreover, the CIE chromaticity coordinates for the composition-optimized Ca-4.93(PO4)(3)Br: 0.07Eu(2+) were located in the blue region at (x=0.1450, y=0.0840), whose color purity was close to that of the commercial blue phosphor BaMgAl10O17:Eu2+. All these results gave an indication that Ca5-x(PO4)(3)Br:xEu(2+) phosphors could serve as a promising blue-emitting candidate for near-UV-pumped white light-emitting diodes. (C) 2017 Elsevier GmbH. All rights reserved.