Sr₃Bi(PO₄)₃:Eu²⁺ Luminescence, Concentration Quenching and Crystallographic Sites

A blue emitting phosphor Sr₃Bi(PO₄)₃:Eu²⁺ is synthesized by a high-temperature solid state method, and its luminescent property is investigated. Sr₃Bi(PO₄)₃:Eu²⁺ can create blue emission under the 332 radiation excitation, and the prominent luminescence in blue (423 nm) due to the 4f5d¹→4f⁷ transition of the Eu²⁺ ion. The crystallographic sites of the Eu²⁺ ion in Sr₃Bi(PO₄)₃ are analyzed, and the 420 and 440 nm emission peaks of the Eu²⁺ ion are assigned to the nine-coordination and eight-coordination, respectively. The emission intensity of Sr₃Bi(PO₄)₃:Eu²⁺ is influenced by the Eu²⁺ doping content, and the concentration quenching effect is observed. The quenching mechanism is the dipole-dipole interaction, and the critical distance of energy transfer is calculated by the concentration quenching method to be approximately 1.72 nm.