Investigations on the luminescence of Ba_2Mg(PO_4)_2:Eu^2+,Mn^2+ phosphors for LEDs

To explore new phosphors with long-wavelength visible emission, a series of Ba2(1-x)Mg1-y(PO4)2:xEu2+,yMn2+ (BMP:xEu2+,yMn2+, 0.2% ≤ x ≤ 5%, 0 ≤ y ≤ 15%) samples were prepared by the solid-state reaction method, and their photoluminescence properties were investigated. When the Eu2+ is single-doped into the BMP matrix, the orange-yellow emission is gained, which is attributed to the Eu2+ 4f7-4f65d1 transition; its excitation spectrum includes a broad wavelength region from 240 to 450 nm. By introducing Mn2+ into the BMP:2.2%Eu2+, a red-shift of the Eu2+ emission band was observed owing to the mixing of the Eu2+ and Mn2+ emissions. The energy transfer from Eu2+ to Mn2+ has been interpreted by using the decay curves. By investigating the thermally stable luminescence of the typical BMP:2.2%Eu2+ and BMP:2.2%Eu2+,10%Mn2+ phosphors, it has been found that the former thermal stability is superior to the latter one. In sum, the above spectral features reveal that the BMP:xEu2+,yMn2+ phosphors could be promising candidates for LEDs application.