A novel red-emitting K2Ca(PO4)F:Eu2+ phosphor with a large Stokes shiftElectronic supplementary information (ESI) available: Configuration states, CPMAS spectra using solid state NMR, PL spectra dependence on the temperature, PLE spectra using pc-LEDs, crystallographic data, atomic coordinates, bond distance and angles, phase transition data, result of CDFT calculations, pc-LEDs performance. See DOI: 10.1039/c7cc08202a

We report a K 2 CaPO 4 F:Eu 2+ phosphor with a new crystal structure. This phosphor has a large Stokes shift and converts near-ultraviolet light to red luminescence without absorption of other visible light. The mechanism was elucidated by applying a constrained density functional theory to the solved crystal structure. We report a K 2 CaPO 4 F:Eu 2+ phosphor with a new crystal structure.