Potential red-emitting phosphor GdNbO₄:Eu³⁺,Bi³⁺ for near-UV white light emitting diodes

A red-emitting phosphor GdNbO₄:Eu³⁺,Bi³⁺ was prepared by a high temperature solid-state reaction technique. The phosphor was characterized by X-ray diffraction (XRD), particle size analyzer and fluorescence spectrometer. The single phase of GdNbO₄:Eu³⁺,Bi³⁺ was obtained at 1150℃ and the average particle diameter was about 2.30 μm. Excitation and emission spectra reveal that the phosphor can be efficiently excited by ultraviolet (UV) light (394 nm) and emit the strong red light of 612 nm due to the Eu³⁺ transition of ⁵D₀→⁷F₂. The optimum content of Eu³⁺ doped in the phosphor GdNbO₄:Eu³⁺ is 20mol%. The phosphor Gd_0.80NbO₄:0.20Eu³⁺,0.03Bi³⁺ shows much stronger photoluminescence intensity and better chromaticity coordinates (x=0.642, 0.352) than GdNbO₄:Eu³⁺. It is confirmed that Gd_0.80NbO₄:0.20Eu³⁺,0.03Bi³⁺ is a potential candidate for near-UV chip-based white light emitting diodes.