Luminescent properties of Na 3Gd 1− xEu x(PO 4) 2 and energy transfer in these phosphors

Abstract

A series of Eu 3+ activated Na 3Gd 1− x Eu x (PO 4) 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 Na 3Gd(PO 4) 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 5D 0 → 7F 1 and forced electric dipole transition 5D 0 → 7F 2 are comparable, and the energy ratio ( 5D 0 → 7F 1/ 5D 0 → 7F 2) 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 5D 0 → 7F J transitions of Eu 3+ 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. Na 3Gd 1− x Eu x (PO 4) 2 has a potential application for white light-emitting diodes.