Controlling Particle Size and Luminescence in Mn4+ Activated K2SiF6

Tuesday, October 13, 2015: 10:30
Phoenix West (Hyatt Regency)
P. K. Nammalwar, D. G. Porob (GE India Technology Centre), R. Hanumantha (GE Global Research, Bangalore), A. A. Setlur (GE Global Research), and J. Murphy (GE Global Research)
Narrow red emitters have attracted large attention within  white LED and backlit display world over the past few years.  This is partially due to renewed interest in red emitting phosphor, K2SiF6:Mn4+ (PFS).  Though, the material is known in literature for more than two decades, its application in white LEDs and display devices can be realized only after some of the key issues in the synthesis of these materials are addressed. In this paper, we discuss  synthesis, controlling particle size and luminescence properties  of Mn4+ doped K2SiF6. Manganese doped Potassium hexafluorosilicate  exists in  cubic  crystal structure with narrow PL emission with a main peak at 631nm with a FWHM of 2nm. Based on the type of application within display or general lighting, the particle size requirement for PFS varies. We have studied various parameters that can influence  particle growth during synthesis in order to obtain PFS of desirable particle size. In the current study we have used variety of anti-solvents (solvents that do not dissolve K2SiF6), including isopropyl alchohol(IPA), acetic acid, Dimethyl sulphoxide (DMSO), acetone, ethanol etc., to initiate crystallization.  By controlling quantity of anti-solvents and process of addition, we have shown better control on particle size distribution.  Further,  in this study we also discuss on influence of anti-solvents on luminescence properties and yield of PFS obtained.