Synthesis, structure, and peculiar green emission of NaBaBO3:Ce3+ phosphors

Abstract

Polycrystalline samples of Ce³⁺-doped NaBaBO₃ (0.5–15 mol%) were prepared by the solid-phase synthesis. The phase formation was confirmed by X-ray powder diffraction (XRD) measurements and structural refinement. The photoluminescence excitation and emission spectra and decay curves were measured. The absolute luminescence quantum efficiency (QE) and the activation energy (ΔE) were reported. Under the excitation of near-UV light, Ce³⁺-doped NaBaBO₃ presents a green-emission band centred at 505 nm from the allowed inter-configurational 4f–5d transition. The maximum absolute QE of NaBaBO₃:Ce³⁺ was measured to be 58% excited with 395 nm light at 300 K. The thermal stability of the green luminescence was evaluated by the luminescence decays as a function of temperature. The phosphor shows an excellent thermal stability on temperature quenching effects. Compared with the reported Ce³⁺-doped alkali metal and alkaline earth orthoborates with the general formula MNBO₃ with only blue luminescence, the peculiarity of NaBaBO₃:Ce³⁺ is the green emission and a high doping concentration in the lattices. The results were discussed on the relationship between the structure and the luminescence properties.