Synthesis, luminescence properties and energy transfer behavior of Na2CaMg(PO4)2:Eu2+, Mn2+ phosphors

Na2CaMg(PO4)2:Eu2+, Mn2+ phosphors were synthesized by a high temperature solid-state reaction. The phase and crystal structures were analyzed. The emission colour of Na2CaMg(PO4)2:Eu2+, Mn2+ phosphors varied from blue to red, which was controlled by altering the concentration ratio of Eu2+ to Mn2+. The photoluminescence and lifetime analysis indicate that there is an efficient energy transfer from the Eu2+ to Mn2+ ions via a dipole–dipole mechanism with the critical distance of ~11 Å. Thermal quenching luminescence results reveal that Na2CaMg(PO4)2:Eu2+,Mn2+ exhibits good thermal stability. Preliminary studies showed that the phosphor might be promising as a light-conversion phosphor for the near UV-pumped white-light LEDs.