Low-voltage cathodoluminescence and Eu/Tb L3-edge XANES of Na1+yCa1−x−2yEuxTbyPO4

• NaCaPO4: Eu2+ exhibits a green emission and resists to the current saturation with low-voltage electron beam excitation.
• Under low-voltage electron beam excitation, NaCaPO4: Tb3+ emits a color-tunable light resulted from cross-relaxation process.
• Eu/Tb L3-edge XANES spectra confirmed the occurrence of Eu3+ and inexistence of Tb4+ ions in all samples.

Eu2+/Tb3+ single-doped and co-doped NaCaPO4 phosphors were synthesized by a high temperature solid-state reaction method. Their photoluminescence, low-voltage cathodoluminescence and Eu/Tb L3-edge X-ray absorption near edge structure (XANES) were studied. Under low-voltage electron beam excitation, NaCaPO4: Eu2+ exhibits a green emission and NaCaPO4: Tb3+ emits a color-tunable light resulted from cross-relaxation process. For co-doped samples NaCaPO4: Eu2+, Tb3+, dominant emission is from f–d transition of Eu2+ and the 5D4–7F5 transition of Tb3+ is overlapped to the former one. Eu/Tb L3-edge XANES spectra confirmed the occurrence of Eu3+ and inexistence of Tb4+ ions in the samples.