Crystal Structure, Characterization, and Luminescence Properties of Mn4+-Doped K3Nb2O4F5

In this paper, we present the high-pressure/high-temperature synthesis and characterization of the potassium fluoridooxidoniobate K3Nb2O4F5. Single-crystal analysis revealed that the phase crystallizes in the trigonal space group R3? ${R\bar{3}}$ m (hR18) with a=5.799(2), c=21.371(4) angstrom, V=622.4(4) angstrom(3) and Z=3 at T=299 K exhibiting a structure type closely related to that of Ba2RbFe2F9. The assignment of the anion positions to oxygen and fluorine is based on crystallographic data and BLBS/CHARDI calculations. Further characterization via EDX spectroscopy was carried out, corroborating the ratio of K to Nb. Doping of the title compound with Mn4+ was achieved in a secondary step using a ball-mill, resulting in a red phosphor material, which was additionally analyzed by luminescence spectroscopy. The emission maximum is located at lambda(max)=630 nm.

Automated summary

This paper presents the synthesis and characterization of K3Nb2O4F5 through high-pressure and high-temperature conditions. The crystal structure of K3Nb2O4F5 is closely related to that of Ba2RbFe2F9. The assignment of anion positions to oxygen and fluorine is based on crystallographic data and calculations. Doping K3Nb2O4F5 with Mn4+ results in a red phosphor material with an emission maximum at λ(max) = 630 nm.