Photoluminescence properties of Ca9Lu(PO4)7:Ce3+, Mn2+ prepared by conventional solid-state reaction

A new red-emitting phosphor Ca9Lu(PO4)7:Ce3+, Mn2+ has been synthesized by solid-state reaction, and its luminescence properties have been investigated. The broad red emission peaked at 645 nm of Mn2+ is greatly enhanced by the sensitizer Ce3+ due to efficient energy transfer from Ce3+ to Mn2+. The energy transfer was demonstrated to belong to a resonant type via a dipole–quadrupole mechanism. The critical distance for Ce3+→Mn2+ energy transfer was calculated to be 15.04 Å by concentration quenching method. Preliminary results indicate that the phosphor might be a promising red phosphor for UV-based white LEDs.