Preparation, structure and luminescence properties of deep red phosphors SrSiN2: Eu2+

This paper reported a novel synthetic route to Eu2+ doped SrSiN2 deep red phosphors for white light-emitting diodes. A series of single-phased and high-efficiency SrSiN2:Eu2+ red phosphors were synthesized based on this method. Their structure, morphology, luminescence, quantum efficiency (QE) and thermal quenching properties were investigated and compared with those of SrSiN2: Eu2+ prepared by the conventional route. It was found that the addition of a small amount of Si3N4 could promote the formation of SrSiN2 from Sr2Si5N8 phase. A highly uniform rod-shaped morphology was obtained based on this method. The X-ray powder diffraction and the Rietveld refinement analysis identified the preferential crystalline orientation growth. Under the blue light excitation, Eu2+ doped SrSiN2 phosphors showed excellent optical properties. Compared with those prepared by the conventional approaches, the external QE of SrSiN2:Eu2+ phosphor was greatly improved, allowing it a promising phosphor for white LEDs.