Investigation on luminescence of emission-tunable Ca 5 Y 3 Na 2 (PO 4 ) 5 SiO 4 F 2 :Eu 2+ ,Tb 3+ ,Mn 2+ phosphors for white LEDs.

To explore new single-phased white-light-emitting luminescent materials, a series of Eu2+-Tb3+-Mn2+ doped Ca5Y3Na2(PO4)5SiO4F2 (CYNPS) phosphors were synthesized by solid-state reaction method. Eu2+ in the CYNPS host shows a light blue emission band covering a broad range from 400 to 800 nm. When the Tb3+ or Mn2+ is codoped with Eu2+, obvious energy transfer from Eu2+ to Tb3+/Mn2+ appears, which increases the emission intensity of Tb3+/Mn2+ efficiently. To achieve white emission, the Eu2+-Tb3+-Mn2+ ions are tridoped. By adjusting the Mn2+ concentration, the emitting-light-color can be tuned conveniently. Warm white light was gained in the CYNPS:0.07Eu2+,0.18Tb3+,0.15Mn2+ phosphor with the chromaticity coordinates and correlated color temperature of (0.396, 0.369) and 3487 K, respectively. The investigation reveals that the present phosphors could have potential application in white LEDs.