Luminescent Properties and Energy Transfer of Eu2+/Mn2+ Codoped Na(Sr,Ba)PO4 and Ba2Mg(BO3)2 Phosphors

Two series of the phosphors Na(Sr,Ba)PO4 and Ba2Mg(BO3)(2) codoped with different concentrations of Eu2+ and Mn2+ were synthesized using a solid-state reaction method. The energy transfer between Eu2+ and Mn2+ in both host crystals was investigated by steady-state and time-resolved photoluminescence measurements. For Na(Sr,Ba)PO4, Eu2+ has an emission centered at 460 nm which overlaps with multiple excitation transition of Mn2+. In contrast, for Ba2Mg(BO3)(2), Eu2+ emission is red-shifted to 612 nm, which causes a single spectral overlap between Eu2+ and Mn2+ energy levels. As a result, the energy transfer efficiency is improved between Eu2+ and Mn2+ in Ba2Mg(BO3)(2) with a maximum energy transfer efficiency of 91% compared to that in Na(Sr,Ba)PO4 with that of 57%.