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

A pink K2MnF5 center dot H2O precipitate is obtained by etching Mg, Fe, Ni, Cu, Zn, or In in an aqueous HF/KMnO4 solution. The pink K2MnF5 center dot 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+ (3d(3)) ions in Mn (IV)F-6(2-) 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 3d(3) (Mn4+) electrons in the cubic K2MnF6 lattice are also determined. (C) 2010 American Institute of Physics. [doi:10.1063/1.3516489]