HF-Free Solid-State Synthesis of the Oxyfluoride Phosphor K3MoOF7:Mn4+

Abstract

K3MoOF7:Mn4+ was synthesized through a facile two-step solid-state synthesis route without using HF. The first step was carried out in copper ampules, which were shut by welding, followed by the second step, a ball milling experiment. The sample was characterized by single-crystal and powder X-ray diffraction, EDX, and luminescence spectroscopy. K3MoOF7 crystallizes in the triclinic space group P1 (no. 2). It features [MoOF5]– units as a main structural motif. At room temperature, seven emission lines are noticeable. The maximum emission line is located at λmax = 627 nm. CIE1931 coordinates could be determined to 0.690(1) and 0.310(1) for x and y, respectively. A luminous efficacy of radiation (LER) of 218 lm Wopt–1 was achieved. Furthermore, temperature dependent luminescence measurements in the range of 25 °C to 100 °C were conducted.