Alkali Metal Hexafluorido Plumbates(IV) A₂[PbF₆] (A=Na−Cs) and Luminescence of the Mn⁴⁺‐substituted Compounds A₂[PbF₆] : Mn (A=Li−Cs) and Li₂[MF₆] : Mn (M=Ti, Ge, Sn)

Abstract

We synthesized eight novel red‐emitting Mn4+‐substituted phosphors of the compositions A2[PbF6] : Mn (A=Li−Cs) and Li2[MF6] : Mn (M=Ti, Ge, Sn) using a dry‐chemical fluorination process which completely avoids the usage of hydrofluoric acid. Compared with the commonly used red‐emitter K2[SiF6] : Mn (KSF) the two synthesized phosphors Na2[PbF6] : Mn and Li2[GeF6] : Mn show a blue‐shift of their emission maximum, Na2[PbF6] : Mn even by 4.2 nm. The compounds were characterized by powder X‐ray diffraction, IR and emission spectroscopy. Additionally, we present the crystal structures of the unsubstituted compounds A2[PbF6] (A=Na−Cs). Na2[PbF6] crystallizes in the trirutile structure type, whereas the other three are isotypic to K2[GeF6] (space group P3‾m ).