Luminescence properties and energy transfer investigations of Ba₂La_{2.85- x} Tb_0.15Eu _x (SiO₄)₃F multicolor phosphor

The Ba₂La_2.85-x Tb_0.15Eu _x (SiO₄)₃F (BLSOF:0.15Tb³⁺, xEu³⁺) multicolor phosphors with apatite structure were synthesized via the solid-state pathway. The crystal structure and luminescence properties of the phosphors were investigated by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), Rietveld refinement, photoluminescence excitation (PLE) and photoluminescence (PL). The luminescence performance of the phosphor was optimum when the concentration of Tb³⁺ was set to be 0.15 mol and the concentration of Eu³⁺ was set to be 0.22 mol. Under the accurate excitation of 373 nm near ultraviolet (n-UV) light, the emitting color of the phosphors can be tuned from green to red with increasing Eu³⁺/Tb³⁺ ratio. It was further proved that the quadrupole-quadrupole (q-q) interaction is responsible for the energy transfer (ET) in the BLSOF:0.15Tb³⁺, 0.22Eu³⁺ phosphor. Owing to the excellent thermal quenching luminescence property, the BLSOF:0.15Tb³⁺, xEu³⁺ phosphor can be applied in n-UV white light emitting diodes (w-LEDs) and serve as the warm part of warm white light.