VUV-UV luminescence of Ce3+, Pr3+ doped and Ce3+–Pr3+ codoped NaLa(PO3)4

A series of NaLa1−xCex(PO3)4, NaLa1−yPry(PO3)4 and NaLa0.7−zCe0.3Prz(PO3)4 phosphors with different doping concentrations (x, y and z values) are prepared through a solid-state reaction route. Five 4f→5d excitation bands of Ce3+ in NaLa(PO3)4 are identified according to the VUV-UV excitation spectra. Influence of doping concentration on the emission spectrum of NaLa1−xCex(PO3)4 is discussed. The lowest 4f→5d excitation band of Pr3+ is verified through the comparison of excitation spectra of Ce3+ and Pr3+. The fluorescence decays of NaLa1−yPry(PO3)4 are studied. Due to the effective spectral overlap between the emission of Pr3+ and the excitation of Ce3+, the Pr3+→Ce3+ energy transfer in NaLa0.7−zCe0.3Prz(PO3)4 phosphors are investigated.