Abstract: Yellowwhite long afterglow phosphors Ba3xP4O13:xEu2+were synthesized through a traditional solid state reaction at a low temperature(1 173 K) in the atmosphere of air. The crystal structure, luminescent properties, afterglow decay properties, thermoluminescence, thermal stability and selfreduction mechanism of Eu2+ ions were studied. The results show that: under the excitation of UV/near UV source, the samples show a broad band peaking at 545 nm, which should be attributed to 5d4f transition of Eu2+ ion, and the samples give off yellow light. At room temperature, the samples display yellow long afterglow after the excitation of UV source with a wavelength of 254 nm, and the lifetime of afterglow seen with naked eyes is more than 30 min. The depth of trap level in this phosphor could be calculated through thermoluminescence analysis, 067 eV approximately. Meanwhile the thermal stability of samples were also tested, and the thermal activation energy was about 031 eV. Besides, Eu3+ ions could be reduced to bivalent ones in the atmosphere of air because abundant PO4 tetrahedra exist in the crystal structure of Ba3P4O13.

Key words: rareearth ion activation, phosphate, long afterglow material, thermal stability, selfreduction