Influence of Bi3+ content on photoluminescence of InNbO4: Eu3+, Bi3+ for white light-emitting diodes

A series of red-emitting phosphors InNbO4: Eu3+, Bi3+ was prepared by a high temperature solid-state reaction. The structure, size distribution and luminescence properties of the phosphors were respectively characterized by X-ray diffraction (XRD), laser particle size and molecular fluorescence spectrometer. The XRD results indicate that the phase-pure samples have been obtained and the crystal structure of the host has not changed under the Eu3+ and Bi3+ co-doping. The test of size distribution shows that the phosphor has a normal size distribution. The excitation spectra illustrate that the dominant sharp peaks are located at 394 nm (F-7(0) -> L-5(6)) and 466 nm (F-7(0) -> D-5(2)). Meanwhile, the emission spectra reveal that the phosphors excited by the wavelength of 394 nm or 466 nm have an intense red-emission line at 612 nm owing to the D-5(0) -> F-7(2) transition of Eu3+. Bi3+ doping has not changed the peak positions except the photoluminescence intensity. The emission intensity is related to Bi3+ concentration, and it is up to the maximum when the Bi3+ -doping concentration is 4 mol%. Due to good photoluminescence properties of the phosphor, the InNbO4: 0.04Eu(3+),0.04Bi(3+) may be used as a red component for white light-emitting diodes.