Small Stokes shift and high thermostability in Ce3+ doped K2BaPO4F phosphors

•Strong near ultraviolet emission with high thermal stability was been observed in Ce3+ doped K2BaPO4F phosphors.•DFT calculations based on refined crystal structure were performed.•The concentration quenching mechanism was confirmed.•The high thermal stability is ascribed to the large band gaps, small phonon energy and rigid lattice structure. Novel K2BaPO4F:Ce3+ phosphors with strong violet-emission and high thermostability were synthesized by a traditional high-temperature solid-state reaction method. The phase composition and crystal structure were investigated in detail by XRD refinement. DFT calculations based on refined crystal structure were performed. A bright emission in the range of 340–390 nm with a small Stokes shift has been observed when excited at about 323 nm in K2BaPO4F:Ce3+ phosphors. The temperature-dependent PL spectra from 80 to 500 K were investigated systematically. The best doping concentration of K2BaPO4F:xCe3+ phosphors was verified and the concentration quenching mechanism was also confirmed. When the temperature increased from 80 K to 500 K, the emission intensity still remains 53 %. The thermal quenching mechanism was explained using the crystal structure investigation and DFT calculation. The strong near-ultraviolet emission intensity and ultra-high thermal stability indicating that the prepared K2BaPO4F:Ce3+ phosphors have potential applications in anti-counterfeiting and solid-state lighting. [Display omitted]