Synthesis and Luminescence Properties of White-Light Emitting Ba₃La(PO₄)₃: Dy³⁺,Eu³⁺ Phosphors

A series of Ba₃La(PO₄)₃:Dy³⁺,Eu³⁺ phosphors were synthesized via a solid-state reaction method. XRD, FE-SEM, and photoluminescence spectra were exploited to characterize the crystal structure and luminescence properties of the prepared phosphors. The XRD results indicated that the pure Ba₃La(PO₄)₃:Dy³⁺,Eu³⁺ phase can be obtained at 1 500℃. However, when a small amount of boric acid was used as co-solvent, the pure Ba₃La(PO₄)₃:Dy³⁺,Eu³⁺ phase can be obtained at 1 400℃. Further XRD check indicates that there is no crystal lattice perturbation induced by co-doping Dy³⁺ and Eu³⁺ in Ba₃La(PO₄)₃ host lattice. Under the excitation of ultraviolet light, the Ba₃La(PO₄)₃:Dy³⁺ phosphors show a cold white luminescence, corresponding to the characteristic transitions of ⁴F_9/2→⁶H_15/2 and ⁴F_9/2→ ⁶H_13/2 of Dy³⁺ at 487 and 578 nm. With the excitation of NUV light, the Ba₃La(PO₄)₃:Eu³⁺ phosphors show an orange-red luminescence, corresponding to the characteristic transitions of ⁴F_9/2→⁶H_15/2 and ⁴F_9/2→ ⁶H_13/2 of Eu³⁺ at 487 and 578 nm. For Ba₃La(PO₄)₃:Dy³⁺,Eu³⁺ phosphor, with the excitation of UNV light, it shows not only the characteristic luminescence of Dy³⁺, but also the characteristic luminescence of Eu³⁺, and its luminescence color can be tuned from cold-white, through warm-white, to orange-red by changing the doping concentration and relative ratio of Dy³⁺ and Eu³⁺. Due to their excellent luminescent properties, the obtained Ba₃La(PO₄)₃:Dy³⁺,Eu³⁺ phosphors have potential application in UV-pumped white light-emitting devices.