Enhanced Photoluminescent Properties and Crystalline Morphology of LiBaPO(4):Tm(3+) Phosphor through Microwave Sintering Method

An investigation of the photoluminescent properties and crystalline morphology of blue emitting LiBa(1−x)PO4:xTm(3+) phosphors with various concentrations (x = 0.005–0.030) of Tm(3+) ions were synthesized by microwave sintering. For comparison, the LiBa(1−x)PO4:xTm(3+) powders sintered at the same sintering condition but in a conventional furnace were also investigated. LiBaPO(4) without second phase was formed no matter which furnace was used. More uniform grain size distributions are obtained by microwave sintering. When the concentration of Tm(3+) ion was x = 0.015, the luminescence intensity reached a maximum value, and then decreased with the increases of the Tm(3+) concentration due to concentration quenching effect. The microwave sintering significantly enhanced the emission intensity of LiBa(1−x)PO4:xTm(3+) phosphors. Additionally, the d-d interaction is the key mechanism of concentration quenching for LiBaPO(4):Tm(3+). The chromaticity (x, y) for all LiBa(1−x)PO(4):xTm(3+) phosphors are located at (0.16, 0.05), which will be classified as a blue region.