Crystal structure refinement and luminescence properties of blue-green-emitting CaSrAl2SiO7:Ce3+, Li+, Eu2+ phosphors

摘要

Ce3+/Li+, Eu2+ singly doped and Ce3+/Li+/Eu2+-co-doped CaSrAl2SiO7 phosphors have been prepared using the conventional solid-state reaction method. The crystal structure of the melilite-type CaSrAl2SiO7 phase and the preferred crystallographic positions of the doped ions were refined using the Rietveld method. The luminescence properties and energy transfer of CaSrAl2SiO7:Ce3+, Li+, Eu2+ were studied in detail. The Ce3+/Li+ activated CaSrAl2SiO7 phosphor has a strong absorption band in the range of 200-450 nm and shows a blue emission centered at 477 nm. When Eu2+ ions are co-doped with Ce3+/Li+, the emission color of CaSrAl2SiO7:Ce3+, Li+, Eu2+ phosphors under the irradiation of 365 nm can be tuned from blue to green via the energy transfer from Ce3+ to Eu2+ ions. Also the involved energy transfer process and the corresponding mechanism between Ce3+ and Eu2+ have been discussed in detail. These results indicate that the as-reported CaSrAl2SiO7:Ce3+, Li+, Eu2+ phosphors have potential applications in near-UV chip pumped white LEDs.