Tunable photoluminescence properties of Ca8NaLa(PO4)6F2:Eu2+,Mn2+ phosphor under UV excitation

• Ca8NaLa(PO4)6F2:Eu2+,Mn2+ was prepared by a combustion-assisted synthesis method.
• The phosphor presents blue and yellow double color emissions.
• Efficient energy transfer from Eu2+ to Mn2+ in this phosphor is observed obviously.
• White emitting was realized in Ca8NaGd(PO4)6F2:0.10Eu2+,0.32Mn2+,0.10B phosphor.

A series of Eu2+ and Mn2+ coactivated Ca8NaLa(PO4)6F2 (CNLF) phosphors have been synthesized by a combustion-assisted synthesis method. The investigation revealed that Ca8NaLa(PO4)6F2 crystallized in a hexagonal crystal system with the space group P63/m (176). The Eu2+ activated phosphors can be efficiently excited in the range of 270–400 nm and give intense blue emission peaking at 451 nm. By codoping the Eu2+ and Mn2+ ions into the CNLF host and singly varying the doping content of the Mn2+ ion, tunable colors from blue to white and eventually to yellow are obtained in CNLF:Eu2+,Mn2+ phosphors under the irradiation of 330 nm. The energy transfer from Eu2+ to Mn2+ in CNLF:Eu2+,Mn2+ has been demonstrated to be a resonant type via a dipole–dipole mechanism and the critical distance of energy transfer from Eu2+ to Mn2+ was estimated to be about 11.9 Å. The investigation indicates that the obtained samples might have potential application in white LEDs.

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