Energy transfer mechanisms in green emitting LiBaPO₄:Tb ³⁺ phosphors

Green emitting LiBa_1-xPO4:xTb³⁺ up-conversion phosphors with various concentrations (x=0.1, 0.2, 0.3, 0.4, 0.5) of Tb ³⁺ ions were synthesized by solid state reaction method at 1300 ° for 3 hour in air. The impure phases were appeared as Tb³⁺ ion concentration was further increased (x more than 0.2). The luminescence intensity reached a maximum when the concentration of Tb3+ ion was x = 0.2, and then decreased with the increases of the Tb³⁺ concentration due to concentration quenching effect. In addition, it is identified that the d-d interaction plays a major role in the mechanism of concentration quenching of LiBaPO₄:Tb³⁺ and all the chromaticity (x, y) of LiBa _1-xPO₄:xTb³⁺ phosphors are located in the green region (0.33, 0.56).