Effect of A+ (A = Li, Na and K) co-doping on enhancing the luminescence of Ca5(PO4)2SiO4:Eu3+ red-emitting phosphors as charge compensator

A series of Ca5-x(PO4)(2)SiO4:xEu(3+) red-emitting phosphors were synthesized through solid-state reaction, and alkali metal ions A(+) (A = Li, Na and K) were co-doped in Ca-5(PO4)(2)SiO4:Eu3+ to improve its luminescence property. The impacts of synthesis temperature, luminescence center Eu3+ concentration and charge compensator A+ on the structure and luminescence property of samples were studied in detail. X-ray diffraction results indicated that prepared Ca-5(PO4)(2)SiO4:Eu3+, A(+) had a standard Ca-5(PO4)(2)SiO4 structure with space group P6(3)/m. Under the excitation of 392 nm, Ca-5(PO4)(2)SiO4:Eu3+ phosphors showed a red emission consisting of several emission peaks at 593 nm, 616 nm and 656 nm, relevant to D-5(0)-> F-7(1), D-5(0)-> F-7(2) and D-5(0)-> F-7(4) electron transitions of Eu3+ ions, respectively. Luminescence intensity and lifetime of Ca-5(PO4)(2)SiO4:Eu3+ can be significantly enhanced through co-doping alkali metal ion A(+), which play an important role as charge compensator. The results suggest that Ca-5(PO4)(2)SiO4:Eu3+, A(+) red phosphors with excellent luminescence property are expectantly served as red component for white light-emitting diodes excited by near-ultraviolet.