Crystal structure and luminescence properties of Bi3+ activated Ca2Y8(SiO4)6O2 phosphors under near UV excitation

Oxyapatite Ca2Y8-x(SiO4)(6)O-2:xBi(3+) phosphor has been prepared via high temperature solid-state reaction. Its crystal structure and PL properties were investigated by X-ray diffraction, photoluminescence excitation and emission spectra. The results indicated that the Ca2Y8(SiO4)(6)O-2 crystallizes as a hexagonal structure with a space group of P6(3)/m and lattice constants of a=b=9.3507 angstrom, c=6.7899 angstrom, alpha=beta=90.00 degrees, gamma=120.00 degrees, V=514.14 angstrom(3); The phosphor has two prominent emission bands: when excited under 320-360 nm, the phosphors emit a broad band centered at 495 nm due to the P-3(1)-S-1(0) transition of Bi3+ in 4f (C-3) sites; when excited under 380 nm, the phosphors emit a broad band centered at 411 nm due to the P-3(1)-S-1(0) transition of Bi3+ in 6h (C-s) sites. The emission color varies from the greenish blue to blue as the excitation wavelength increases from 335 to 380 nm. The optimal intensity of emission band was observed when x=0.015 in the Ca2Y8-x(SiO4)(6)O-2:xBi(3+) series. The average critical distance Rc among Bi3+ ions is determined to be 20.15 angstrom. (C) 2016 Published by Elsevier Inc.