A low-temperature co-precipitation approach to synthesize fluoride phosphors K2MF6:Mn4+(M = Ge, Si) for white LED applications

A new class of Mn⁴⁺activated alkali-metal hexafluoride red phosphors are emerging for white light-emitting diodes because of their sharp red line²E_g→⁴A_2gemissions (600–650 nm) excited by irradiation of⁴A_2g→⁴T_1g(320–380 nm) and⁴A_2g→⁴T_2g(380–500 nm) transitions.