Crystal structure, luminescent properties and white light emitting diode application of Ba3GdNa(PO4)3F:Eu2+ single-phase white light-emitting phosphor

A series of single-phase white-light-emitting phosphors, Eu2+-activated Ba3GdNa(PO4)3F phosphors were synthesized by solid-state reactions. The crystal structure of Ba3GdNa(PO4)3F was been identified by Rietveld refinement of X-ray diffraction pattern. The Eu2+-activated Ba3GdNa(PO4)3F phosphors exhibit broad excitation spectra from 250 to 420 nm, which matched well with the n-UV LED chips. Under the excitation of 365 nm, the emission spectrum almost covered the entire visible region including two emission bands peaked at 472 nm and 640 nm. Three different Eu2+ emission centers in Ba3GdNa(PO4)3F:Eu2+ phosphor were confirmed by their fluorescence decay lifetimes. The optimal concentration of Eu2+ in Ba3GdNa(PO4)3F:xEu2+ was 3 mol% and the corresponding concentration quenching mechanism was verified to be exchange coupling interaction. Furthermore, the white light-emitting diode fabricated with Ba3GdNa(PO4)3F:0.05Eu2+ phosphor and a 370 nm UV chip has a CIE of (0.3267, 0.2976) with a color-rendering index of 78.4 at the CCT of 5287 K.