Novel Mn4+-activated oxyfluoride Cs2NbOF5:Mn4+ red phosphor for warm white light-emitting diodes

Novel red-emitting phosphor Cs2NbOF5:Mn4+ was prepared via the ion exchange method, and its crystal structure, composition and morphology were characterized by powder X-ray diffraction, energy-dispersive X-ray spectroscopy and scanning electron microscopy. Meanwhile, the influence of Mn4+ molar ratio on luminescence properties of Cs2NbOF5:Mn4+ has been investigated. The phosphor prepared with the Nb2O5/K2MnF6 molar ratio of 20:1 can emit intense red light under blue light excitation and improve the performances of white light-emitting diode with high color rendering index of 88.4 and low correlated color temperature of 3631 K, so this new red-emitting phosphor could find application on solid-state emitting diode.