Crystal structure and variation of luminescence properties of (Ba,Ca)Si 7 N 10 :Eu 2+ as a function of the Eu and Ca concentration

Cyan-emitting (Ba,Ca)Si7N10:Eu2+ was synthesized using a high-temperature graphite furnace. Crystallographic data for BaSi7N10:0.1Eu(2+) were obtained by Rietveld refinement and discussed compared with undoped BaSi7N10. The excitation spectra peaked at 368 nm and decay times were apparently different from those of earlier papers, and these differences were explained by the structural analyses. The substitution of Ca2+ ions for Ba2+ ions increased the emission intensity by approximately 130%, as this resulted in local lattice modification. The findings indicate that (Ba,Ca)Si7N10:Eu2+ phosphors are highly stable and well suited for use in white LEDs pumped by near ultraviolet sources. (C)2014 Optical Society of America