Luminescent properties of single Dy3+ ions activated Ca3Gd7(PO4)(SiO4)5O2 phosphor

Single Dy3+ ions activated Ca3Gd7(PO4)(SiO4)(5)O-2: Dy3+ (CGPS: Dy3+) phosphors were successfully synthesized by solid-state reaction method. The X-ray diffraction results confirm that the as-prepared CGPS: Dy3+ samples are pure CGPS hexagonal phase. Moreover, the substitution of Dy3+ for Gd3+ in CGPS host leads to the major diffraction peaks moving towards larger angle due to a smaller ions radius of Dy3+ than Gd3+. Upon excitation of 275 nm and 349 nm ultra violet (UV) that are respectively attributed to S-8 -> 6I transitions of Gd3+ and H-6(15/2) -> P-6(7/2) transition of Dy3+ , the characteristic emission of Dy3+ ions such as F-4(9/2) -> H-6(15/2) (480 nm) and F-4(9/2) -> H-6(13/2) (572 nm) can be clearly observed. A high ratio of yellow emission to blue emission (Y/B) implies that De(3+) ions prefer to occupy low-symmetry 6h (CO sites in CGPS matrix. Therefore, white light can be obtained from Dy3+ mono-doped CGPS: Dy3+ phosphor with CIE chromaticity coordinates of (x = 0328, y = 0.343). By calculation, the mechanism of concentration quenching between Dy3+ ions is electric dipole-dipole interaction. In addition, the energy transfer (ET) from Gd3+ to Dy3+ can also be observed. These results suggest that CGPS: Dy3+ phosphors could be a promising candidate for UV-based white light illumination. (C) 2014 Elsevier B.V. All rights reserved.