A new red phosphor BaGeF6:Mn4+: hydrothermal synthesis, photo-luminescence properties, and its application in warm white LED devices

In this work, we report a new and efficient red phosphor BaGeF6:Mn4+ (denoted as BGFM) by hydrothermally etching BaCO3 and GeO2 in HF solution with an optimized KMnO4 concentration. The crystal structure and morphology were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) in detail. The influence of synthesis conditions on its photo-luminescent (PL) properties has been investigated comprehensively. It can present broad adsorption and sharp emissions in blue and red ranges respectively. The white LED device made of a blue GaN chip merged with a YAG:Ce-BGFM mixture presents warmer white light than that merged with only one YAG:Ce component.