Enhanced red emission from Eu3+-Bi3+ co-doped Ca2YSbO6 phosphors for white light-emitting diode

Bi3+ and Eu3+ ions co-doped Ca2YSbO6 have been prepared via high temperature solid-state reaction. Its crystal structure and photoluminescence properties were investigated by X-ray diffraction patterns, diffuse reflection spectra, photoluminescence excitation and emission spectra. The results indicated that the Ca2YSbO6 crystallizes as a monoclinic structure with a space group of P21/n, with the lattice parameters related to that of the double perovskite by a = 5.5995 angstrom, b = 5.7964 angstrom, c = 8.0507 angstrom, alpha = gamma = 90.00 degrees, beta = 89.8943 degrees. The Ca2YSbO6:Eu3+ can be excited by ultraviolet, near-ultraviolet, and blue lights, and a strong red emission located at 614 nm (D-5(0)-> F-7(2)) of Eu3+ ions was observed in all samples. By co-doping Bi3+ ions in Ca2YSbO6:Eu3+, the excitation band shifts to the long-wavelength region, and the red emission intensity was remarkably enhanced. With 5 mol% Bi3+ doped in Ca2YSbO6:Eu3+, the relative intensity of Ca2Y0.80Bi0.05Eu0.15SbO6 was enhanced by 327%, 389% and 348% excited at 290 nm, 400 nm and 470 nm compared with those of Ca2Y0.85Eu0.15SbO6, respectively. The composition-optimized Ca2Y0.8SbO6:0.15Eu(3+), 0.05Bi(3+) phosphor with strong red emission and good CIE chromaticity coordinate shows great potential for applications in white light-emitting diodes. (C) 2015 Elsevier B.V. All rights reserved.