Luminescence Enhancement of Red‐Emitting Sr9MnK(PO4)7 Phosphor via Energy Transfer and Charge Compensation

It is an urgent need to explore high‐efficiency and high‐purity red‐emitting phosphors in white light‐emitting diodes (LEDs) application. Herein, the synthesis and luminescence properties of Mn‐based Sr 9 MnK(PO 4 ) 7 phosphor are reported. X‐ray diffraction (XRD) measurement and Rietveld structural refinement confirm that Sr 9 MnK(PO 4 ) 7 is crystallized in the trigonal Sr 9 Fe 1.5 (PO 4 ) 7 type structure with the space group of (166). Eu 2+ ‐doped Sr 9 MnK(PO 4 ) 7 phosphor exhibits a broad excitation spectrum peaked at 394 nm and emits bright reddish‐orange light centered at 610 nm. Moreover, the introduction of the Ce 3+ ion substantially enhances the intensity of Mn 2+ emission. Here, Ce 3+ acts as a charge compensator rather than a sensitizer, as confirmed by spectral analysis and various chemical techniques. On the base of the energy transfer between Eu 2+ and Mn 2+ coupled with charge compensation, a high‐brightness red‐emitting Sr 9 MnK(PO 4 ) 7 :Eu 2+ ,Ce 3+ phosphor is obtained.