K3WOF7:Mn4+ ‒ A Red Oxyfluoride Phosphor

Abstract Synthesis of K3WOF7:Mn4+ was accomplished via a facile two-step solid-state method. Characterization of the material was carried out by means of single-crystal and powder X-ray diffraction, energy dispersive X-ray spectrometry, as well as luminescence spectroscopy. The substance crystallizes in the monoclinic crystal system in space group P21/c (no. 14) with the lattice parameters a = 884.2(1), b = 1379.9(1), c = 679.7(1) pm, and β = 93.04(1)°. The crystal structure features a quasi-isolated [WOF5]‒ building block as its main motif. The material exhibits a red luminescence under excitation with blue light. The maximum-intensity emission line is located at λmax ≈ 627 nm and the CIE1931 coordinates of the phosphor are 0.689 and 0.310 for x and y, respectively.