Structures and luminescent properties of single-phase La5.90−xBa4+x(SiO4)6−x(PO4)xF2:0.10Ce3+ phosphors

A series of blue-emitting La5.90−xBa4+x(SiO4)6−x(PO4)xF2:0.10Ce3+ (x= 0, 1, 2, and 3) phosphors with apatite structure were synthesized by a solid-state reaction. The crystal structure and the photoluminescence properties were investigated in detail. The crystallographic occupancy of Ce3+ in La2.90Ce0.10Ba7(SiO4)3(PO4)3F2 and La5.90Ce0.10Ba4(SiO4)6F2 were studied based on Rietveld refinements results and the crystal chemistry rules. La5.90−xBa4+x(SiO4)6−x(PO4)xF2:0.10Ce3+ exhibited strong blue light emission in the range of 407-414 nm with high thermal stability upon excitation at 276 nm. Besides, the activation energy E of La5.90Ce0.10Ba4(SiO4)6F2 and La2.90Ce0.10Ba7(SiO4)3(PO4)3F2 phosphors were calculated to be 0.152 and 0.177 eV. These results suggest that La5.90−xBa4+x(SiO4)6−x(PO4)xF2:0.10Ce3+ is a potential blue phosphor candidate for near-UV-pumped w-LEDs.