Efficient sensitization of Eu~(2+)/Mn~(2+) emissions by Ce~(3+) doping in NaMgPO_4 host under UV excitation

摘要

A series of Ce~(3+)/Eu~(2+)/Mn~(2+)-tridoped NaMgPO_4 phosphors were synthesized using the combustion-assisted synthesis method. The luminescence properties and energy transfer from Ce~(3+)/Eu~(2+) to Mn~(2+) in NaMgPO_4 host have been studied. Co-doping Ce~(3+)/Mn~(2+) is proved to be an ineffective approach to enhance the red emission of Mn~(2+), while effective energy transfer from Eu~(2+) to Mn~(2+) occurs in NaMgPO_4:Eu~(2+),Mn~(2+) due to good spectrum overlap between the emission band of NaMgPO_4:Eu~(2+) and the excitation band of NaMgPO_4: Eu~(2+),Mn~(2+). NaMgPO_4:Eu~(2+),Mn~(2+) phosphor shows a blue emission centered at 442 and a red emission peaking at 635 nm, which could be ascribed to the allowed 5d-4f transition of Eu~(2+) ions and the ~4T_1(~4G)-~6A_1(~6S) transition of Mn~(2+) ions, respectively. Co-doping Ce~(3+) ions can greatly enhance both the emission intensities of Eu~(2+) and Mn~(2+) ions, which is attributed to an efficient Ce~(3+) → Eu~(2+) → Mn~(2+) energy transfer and an increase in the number of luminescent centers (Eu~(2+)) on Ce doping.