Synthesis and luminescence of Eu(3+)-doped in triple phosphate Ca8MgBi(PO4)7 with whitlockite structure

Triple whitlockite-type structure-based red phosphors Ca8 MgBi1-x(PO4)7:xEu(3+) (x = 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 route and characterized by their X-ray crystal structures. The X-ray diffraction (XRD) patterns, Fourier transform infrared spectra, morphologies, photoluminescence spectra, UV/Vis reflectance spectra, decay times and the International Commission on Illumination (CIE) chromaticity coordinates of Ca8MgBi1-x(PO4)7:xEu(3+) were analyzed. Eu-doped Ca8MgBi(PO4)7 phosphors exhibited strong red luminescence with peaks at 616 nm due to the (5)D0 → (7)F2 electric dipole transition of Eu(3+) ions after excitation at 396 nm. The UV/Vis spectra indicated that the band gap of Ca8MgBi0.30(PO4)7:0.70Eu(3+) is larger than that of Ca8MgBi(PO4)7. The phosphor developed in this study has great potential as a red-light-emitting phosphor for UV light-emitting diodes.