Photoluminescent properties of K2GeF6:Mn4+ red phosphor synthesized from aqueous HF/KMnO4 solution

Abstract

A simple method of synthesizing K2GeF6:Mn4+ red phosphor has been demonstrated by wet chemical etching of Ge shots in HF/KMnO4 mixed solution. The x-ray diffraction pattern suggests that the synthesized phosphor has the trigonal structure (space group=D3d3–P3¯m1). The optical properties of K2GeF6:Mn4+ are investigated using photoluminescence (PL) and PL excitation spectroscopies. The room-temperature zero-phonon line emission and excitation energies in K2GeF6:Mn4+ are determined to occur at ∼1.99 eV (E2→A42), ∼2.44 eV (A42→T42), and ∼2.80 eV (A42→T41). Some local vibronic emission modes are split in energies of about 5 meV due to the trigonal distortion of the MnF6−2 octahedra. The temperature-dependent PL properties can be reasonably explained on the basis of the Bose–Einstein statistics.