Photoluminescence and radioluminescence of pure and Ce3+ activated Na3Gd(PO4)2

The spectroscopic properties of Na3Gd(PO4)2 and Na3Gd(PO4)2:Ce3+ phosphors in the VUV–UV spectral range were investigated. Five excitation bands of Ce3+ ions at Gd3+ sites are observed at wavelengths of 205, 246, 260, 292, and 321 nm. Doublet Ce3+ 5d → 4f emission bands are observed at 341 and 365 nm with a decay constant τ1/e around 26 ns. The X-ray excited luminescence of Na3Gd0.99Ce0.01(PO4)2 at room temperature shows a photon yield of ∼17,000 photons/MeV of absorbed X-ray energy.

Research highlights
► The spectroscopic properties of phosphors Na3Gd(PO4)2:Ce3+ in the VUV–UV range were investigated.
► Though there are different Gd3+ lattice sites, Ce3+ ions preferably enter one site.
► It was found that the phosphors show a reasonable light yield under X-ray excitation.