Photoluminescent properties of cubic K2MnF6 particles synthesized in metal immersed HF/KMnO4 solutions

Abstract

A pink K2MnF5⋅H2O precipitate is obtained by etching Mg, Fe, Ni, Cu, Zn, or In in an aqueous HF/KMnO4 solution. The pink K2MnF5⋅H2O precipitate typically contains K2MnF6 particles, which exhibit photoluminescence in the red spectral region under blue or UV excitation. The observed red emission is ascribed to the Mn4+ (3d3) ions in Mn(IV)F62− octahedra promoted by the activation of local vibronic modes. The absence of a strong zero-phonon line emission suggests that the synthesized K2MnF6 particles have a cubic symmetry (space group=Fm3m). The energy states and crystal field parameter of the 3d3 (Mn4+) electrons in the cubic K2MnF6 lattice are also determined.