Luminescent properties of Na3Gd1−xEux(PO4)2 and energy transfer in these phosphors

A series of Eu3+ activated Na3Gd1−xEux(PO4)2 (0 ≤ x ≤ 1) phosphors were synthesized by solid-state reaction method. The structures and photo-luminescent properties of these phosphors were investigated at room temperature. The results of XRD patterns indicate that these phosphors are isotypic to the orthorhombic Na3Gd(PO4)2. The excitation spectra indicate that these phosphors can be effectively excited by near UV (370–410 nm) light. The intensities of magnetic dipole transition 5D0 → 7F1 and forced electric dipole transition 5D0 → 7F2 are comparable, and the energy ratio (5D0 → 7F1/5D0 → 7F2) is 1.1. The emission spectra exhibit strong reddish orange performance (CIE chromaticity coordinates: x = 0.62, y = 0.38), which is due to the 5D0 → 7FJ transitions of Eu3+ ions. The correlation between the structure and the photo-luminescent properties of the phosphors was studied. The energy transfer and concentration quenching of the phosphors were discussed. Na3Gd1−xEux(PO4)2 has a potential application for white light-emitting diodes.

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► The photoluminescence properties of Na3Gd1−xEux(PO4)2 were investigated in detail.
► The correlation between the structure and luminescent properties was discussed.
► Demonstrated that Eu3+ activated phosphor based on NUV LED should be heavy doped.
► Energy transfer was observed and the mechanisms were discussed.