Synthesis of SrLu₂O₄:Eu²⁺ red phosphors and their photoluminescence properties

New red-emitting Eu²⁺-doped SrLu₂O₄ phosphors were synthesized by a solid state reaction, and the effects of starting material composition, annealing temperature, and Eu²⁺ doping concentration on the phase formation and photoluminescence (PL) properties were investigated. A single phase SrLu₂O₄:Eu²⁺ phosphor was obtained between 1400 and 1500 °C in Sr-rich condition under 5% H₂/N₂ atmosphere. As-synthesized SrLu₂O₄:Eu²⁺ phosphors exhibited a strong red emission centered at 610 nm under the excitation of λ_ex=450 nm. The highest emission intensity was observed in 0.004 mol Eu-substituted composition, which was ~85% compared to that of commercial (Sr,Ca)AlSiN₃:Eu²⁺ phosphor. SrLu₂O₄:Eu²⁺ phosphors showed a strong thermal quenching, which suggests a high potential as an optical temperature sensor.