Red-emitting oxonitridosilicate phosphors Sr2SiNzO4-1.5z:Eu2+ for white light-emitting diodes: structure and luminescence properties

A novel red-emitting oxonitridosilicate phosphors, Sr2SiNzO4-1.5z:Eu2+ (0.7 < z < 1.2), was prepared by solid state reaction in NH3-N-2 atmosphere. The crystal structure was determined by Rietveld analysis on powder X-ray data. Sr(2)SiNzO(4-1.5z) (0.7 < z < 1.2) crystallizes in an orthorhombic structure with the space group of Pmnb: ba-c (no. 62), and cell parameter a 5.67366(5) angstrom, b 7.09777(4) angstrom, c 9.75112(1) angstrom. Sr2SiNzO4-1.5z:Eu2+ (0.7 < z < 1.2) exhibited broad-band red emission centred at similar to 620 nm (FWHM approximate to 95 nm) under blue light irradiation with a high QE value of 78.0% and good thermal stability, its emission intensity remains 87% at 150 degrees C of that measured at room temperature. The outstanding luminescent properties allow it to be an attractive red luminescent material for white LEDs.