Crystal structure, luminescent properties and white light emitting diode application of Ba 3 GdNa(PO 4 ) 3 F:Eu 2+ single-phase white light-emitting phosphor

Abstract A series of single-phase white-light-emitting phosphors, Eu 2+ -activated Ba 3 GdNa(PO 4 ) 3 F phosphors were synthesized by solid-state reactions. The crystal structure of Ba 3 GdNa(PO 4 ) 3 F was been identified by Rietveld refinement of X-ray diffraction pattern. The Eu 2+ -activated Ba 3 GdNa(PO 4 ) 3 F 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 Eu 2+ emission centers in Ba 3 GdNa(PO 4 ) 3 F:Eu 2+ phosphor were confirmed by their fluorescence decay lifetimes. The optimal concentration of Eu 2+ in Ba 3 GdNa(PO 4 ) 3 F: x Eu 2+ was 3 mol% and the corresponding concentration quenching mechanism was verified to be exchange coupling interaction. Furthermore, the white light-emitting diode fabricated with Ba 3 GdNa(PO 4 ) 3 F:0.05Eu 2+ 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.