Mn(IV)-Substituted Metal(II) Hexafluorido Metallates(IV): Synthesis, Crystal Structures, and Luminescence Properties

Abstract

We synthesized 16 novel red-emitting Mn(IV)-substituted phosphors of the compositions MgGeF6 : Mn, MgPbF6 : Mn, CaMF6 : Mn (M=Ge, Sn, Pb, Zr, Hf), SrSnF6 : Mn, “SrTiF6 : Mn”, BaPbF6 : Mn, ZnMF6 : Mn (M=Sn, Pb, Zr, Hf), and CdMF6 : Mn (M=Pb, Hf) using a dry-chemical fluorination process completely avoiding hydrofluoric acid. In comparison with the commonly used red-emitter K2SiF6 : Mn (KSF) with its emission maximum at 630.8 nm, all above Ca and Sr compounds and CdHfF6 : Mn show a blue-shift of their emission maxima, the compound SrSnF6 : Mn even by 4.2 nm down to 626.6 nm. The compounds were characterized by powder X-ray diffraction, IR and emission spectroscopy. We additionally present the crystal structures of the unsubstituted compounds CaZrF6, CaHfF6, CaPbF6, CdZrF6, CdHfF6, and MgHfF6, which all crystallize isotypic in the NaSbF6 structure type. The compound “SrTiF6” was characterized by powder XRD and studied with evolutionary structure prediction methods, but its crystal structure could not yet be solved.