A Novel Blue‐Emitting Phosphor of Eu 2+ ‐Activated Magnesium Haloborate Mg 3 B 7 O 13 Cl

Eu 2+ ‐doped magnesium haloborate Mg 3 B 7 O 13 Cl was synthesized by the conventional high‐temperature solid‐state reaction. The phase formation was confirmed by X‐ray powder diffraction ( XRD ) measurements and structure refinement. The photoluminescence excitation and emission spectra, and decay curves were measured. Under the excitation of near‐ UV light, Eu 2+ ‐doped Mg 3 B 7 O 13 Cl presents a narrow blue‐emitting band centered at 423 nm. The maximum absolute quantum efficiency ( QE ) of Mg 3 B 7 O 13 Cl : Eu 2+ phosphor was measured to be 80% excited at 385 nm light at 300 K. The thermal stability of the blue luminescence was evaluated by the luminescence decays as a function of temperature. The phosphor shows an excellent thermal stability on temperature quenching effects. Moreover, Mg 3 B 7 O 13 Cl : Eu 2+ phosphor shows scintillation characteristics excited by X ‐ray irradiation at room temperature and presents a blue luminescence band with a fast lifetime of 600 ns.