Preparation of Ca_4Mg_5(PO_4)_6:Eu~(2+), Mn~(2+) phosphor and its photoruminescence properties

摘要

Eu~(2+) and Mn~(2+) singly doped and Eu~(2+)/Mn~(2+)-codoped Ca_4Mg_5(PO_4)_6 phosphors were synthesized via combustion synthesis. Mn~(2+)-singly doped Ca4Mg5(PO4)6 phosphor exhibits a single red emission in the wavelength range of 500-700 nm due to the ~4T_1(~4G)→~6A_1(~6S) transition of Mn~(2+). Eu~(2+)/Mn~(2+) co-doped phosphor emits two distinctive luminescence bands: a blue one centered at 442 nm originating from Eu~(2+) and a broad red-emitting one peaked at 609 nm from Mn~(2+). Energy transfers from Eu~(2+) to Mn~(2+) were discovered by directly observing significant overlap of the excitation spectrum of Mn~(2+) and the emission spectrum of Eu~(2+) as well as the systematic relative decline and growth of emission bands of Eu~(2+) and Mn~(2+), respectively. Based on the principle of energy transfer, the relative intensities of blue and red emission could be tuned by adjusting the contents of Eu~(2+) and Mn~(2+).