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°C 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 Gd0.80NbO4:0.20Eu3+,0.03Bi3+ shows much stronger photoluminescence intensity and better chromaticity coordinates (x=0.642, 0.352) than GdNbO4:Eu3+. It is confirmed that Gd0.80NbO4:0.20Eu3+,0.03Bi3+ is a potential candidate for near-UV chip-based white light emitting diodes.