A novel red-emitting phosphor Ca9Bi(PO4)7:Eu3+ for near ultraviolet white light-emitting diodes

Red phosphors Ca9Bi1-x(PO4)(7):xEu(3+) (x = 0.06, 0.10, 0.20, 0.30, 0.40, 0.50, 0.60, 0.70, 0.80 and 1.00) were synthesized by a conventional solid-state reaction (SSR) route. The X-ray diffraction patterns, photoluminescence spectra, ultraviolete-visible reflection spectroscopy, decay time and the International Commission on Illumination (CIE) chromaticity coordinates of these compounds were characterized and analyzed. The Eu-doped Ca9Bi(PO4)(7) phosphors exhibited strong red luminescence which peaks located at 615 nm due to the D-5(0)-->F-7(2) electric dipole transition of Eu3+ ions after excitation at 393 nm. Ultraviolete-visible spectra indicated that the band-gap of Ca9Bi0.30(PO4)(7):0.70Eu(3+) is larger than that of Ca9Bi(PO4)(7). The results indicate that the phosphor Ca9Bi0.30(PO4)(7):0.70Eu(3+) can be a suitable red-emitting phosphor candidate for LEDs. (C) 2014 Elsevier B.V. All rights reserved.