Energy Transfer and Tunable Luminescence of NaLa(PO3)4:Tb3+/Eu3+ under VUV and Low-Voltage Electron Beam Excitation

Series of NaLa(PO 3 ) 4:Tb 3+ /Eu 3+ phosphors were prepared by a high-temperature solid-state reaction technique. Structure refinements were performed based on powder X-ray diffraction (XRD) data. VUV–UV–vis photoluminescence (PL), fluorescence decays, time-resolved emission spectra (TRES), and low-voltage cathodoluminescence (CL) spectra were utilized to investigate the luminescence and energy transfer processes. Under VUV–UV light and low-voltage electron beam excitation, NaLa(PO 3 ) 4:Tb 3+ and NaLa(PO 3 ) 4:Eu 3+ exhibit characteristic emissions of Tb 3+ ( 5 D 4 → 7 F J ) and Eu 3+ ( 5 D 0 → 7 F J ), respectively. By adjusting the doping concentration of Eu 3+ ions in NaTb 0.70 La (0.30- x ) Eu x (PO 3 ) 4, tunable emission colors are realized in a large color gamut, in which energy transfer from Tb 3+ to Eu 3+ was observed and discussed in detail. On the basis of the good VUV–vis PL and CL properties, NaLa(PO 3 ) 4:Tb 3+ /Eu 3+ phosphors might be promising for applications in plasma display panels (PDPs) and field emission displays (FEDs).