Preparation and photoluminescence properties of MgNb2O6:Eu3+, Bi3+ red-emitting phosphor

Rare earth Eu³⁺-doped MgNb₂O₆ red-emitting phosphor was prepared by solid-state reaction. Structure and photoluminescence properties of the samples were characterized by X-ray diffraction (XRD), scan electron microscopy (SEM) and fluorescence spectrophotometer. Meanwhile, the effect of the co-activator Bi³⁺ on the PL of the MgNb₂O₆:Eu³⁺ phosphor was studied. The results showed that the pure phase of MgNb₂O₆ could be available after firing at 1200 °C. The Mg_1?x Nb₂O₆:Eu _x ³⁺ phosphors could be effectively excited by the UV irradiation (273 nm) and emit red light at 615 nm due to the forced electric dipole ⁵ D ₀ → ⁷ F ₂ transitions on Eu³⁺, which indicated that Eu³⁺ occupied the non-inversion symmetry sites in the MgNb₂O₆ host lattice. So, the addition of the co-activator Bi³⁺ not only increased the excitation band of the MgNb₂O₆:Eu³⁺ phosphor at about 330 nm, but also strengthened the PL intensity at 615 nm. Therefore, MgNb₂O₆:Eu³⁺, Bi³⁺ might find application to InGaN chip-based white light emitting diodes.