Synthesis and efficient blue-emitting of Eu2+-activated borate fluoride BaAlBO3F2

•A novel blue-emitting BaAlBO3F2Cl:Eu2+ phosphor was firstly developed.•Crystal structures and phase formations were investigated.•The detailed luminescence properties and absolute quantum efficiency were reported.•BaAlBO3F2Cl:Eu2+ has high QE and thermal stability because of rigid lattices with F-containing.

Eu2+-doped borate fluoride BaAlBO3F2 was synthesized by the conventional high temperature solid state reaction. The crystal phase formations were confirmed by X-ray powder diffraction (XRD) measurements and the structure refinement. The photoluminescence (PL) excitation and emission spectra, and the decay curves were investigated. Eu2+-doped BaAlBO3F2 phosphor can be efficiently excited by near-UV light and presents narrow blue luminescence band centered at 450 nm. The maximum absolute quantum efficiency (QE) of BaAlBO3F2:0.05Eu2+ phosphor was measured to be 76% excited at 398 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 with high thermal activation-energy on temperature quenching effects because of the rigid crystal lattices.