Improving the energy efficiency of artificial lighting is of major interest for both economic and environmental reasons. One type of lighting that shows promise in accomplishing this goal is phosphor conversion-LEDs (PC-LEDs). One class of compounds that are promising as phosphor coatings for such devices are the anti-perovskite oxyfluorides of the general form A3MO4F, where A is a divalent cation and M is a trivalent cation. Two oxyfluorides of that form that have been recently synthesized are Sr3AlO4F and Sr3GaO4F.1 Previously, effective phosphors have been designed using the substitution of rare earth metals on the A site2,3; however, for use in PC-LEDs it would be preferable to avoid the use of strategic materials. Therefore, substituting manganese(II) and tin(II) on the A site has been investigated. Rare earth-free Sr2.5-xBa0.5A'xMO4F materials were synthesized, where A’=Mn, Sn, M=Al, Ga, and x=0, 0.025, 0.05, 0.075, 0.1. Above 0.1 equivalents of transition metal it was observed that the dopant metal was not fully incorporated into the material. Barium was added as a codopant as the larger barium fits in the ten coordinate site better than strontium as shown by its higher bond valence sum and lower global instability, stabilizing the structure.4 Structural characterization of these materials based on powder X-ray diffraction data and preliminary physical characterization studies are presented here. References: 1. Vogt, T.; Woodward, P. M.; Hunter, B. A.; Prodjosantoso, A. K.; Kennedy, B. J. Sr3MO4F (M=Al, Ga) - A New Family of Ordered Oxyfluorides. J. Solid State Chem. 1999, 144, 228-231. 2. Park, S. Luminescent properties of Sr2.5-3x/2Ba0.5SmxAlO4F oxyfluorides. J. Lumin. 2011, 132, 875-878. 3. Park, S.; Vogt, T. Luminescent phosphors, based on rare earth substituted oxyfluorides in the A(1)3-xA(2)xMO4F family with A(1)/A(2) = Sr, Ca, Ba and M = Al, Ga. J. Lumin. 2009, doi:10.1016/j.jlumin.2009.04.005. 4. Sullivan, E.; Avdeev, M; Vogt, T. Structural distortions in Sr3-xAxMO4F (A = Ca, Ba; M = Al, Ga, In) anti perovskites and corresponding changes in photoluminescence. J. Solid State Chem. 2012, 194, 297-306.

Synthesis and characterization of rare-earth free phosphors with application to PC-LED lighting

249th National Meeting (2015)

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