Luminescence properties of Ce3+ and/or Mn2+ activated Ca10K(PO4)7 under ultraviolet and vacuum ultraviolet excitation

New Ce3+ and/or Mn2+ activated Ca10K(PO4)7 phosphors were prepared by solid-state reaction, and their photoluminescence properties upon ultraviolet and vacuum ultraviolet excitation were investigated. Under 254 nm excitation, a series of Ca10K(PO4)7:xMn2+ samples exhibit two emission bands at 463 and 650 nm, which could be attributed to oxygen defects and 4T1–6A1 transition of Mn2+, respectively. And an energy transfer from defects to Mn2+ has been observed. With the Mn2+ content increased, the emitting hues of Ca10K(PO4)7:Mn2+ can range from blue to red. By co-doping Ce3+ to Ca10K(PO4)7:Mn2+, the emission intensity of Mn2+ is strongly enhanced due to an efficient energy transfer by [Ce3+ → Mn2+] and [defects → Ce3+ → Mn2+]. But under 147 nm excitation, the emission intensity of Mn2+ in Ca10K(PO4)7:0.25Mn2+ decreases slightly compared with that in Ca10K(PO4)7:025Mn2+, 0.1Ce3+, 0.1K+ due to the host sensitization competition between Ce3+ and Mn2+.