Synthesis, crystal structure and photoluminescence of novel blue-emitting Eu2+-doped (SiC)x–(AlN)1−xphosphors by a nitriding combustion reaction

Abstract

Novel blue-emitting phosphors with the chemical composition of (SiC)x–(AlN)1−x:yEu2+ (x = 0.06–0.50, y = 0.001–0.01) were synthesized by a nitriding combustion reaction route, and the crystal structure, luminescence properties and thermal stability of the (SiC)x–(AlN)1−x:yEu2+ phosphors were investigated by theoretical and experimental approaches. First-principles calculation results prove that the solid solution of SiC with AlN promotes the doping of Eu2+ ions into the (SiC)x–(AlN)1−x host lattice, and Eu2+ ions tend to occupy Al sites of the host. The synthesized (SiC)x–(AlN)1−x:yEu2+ phosphors absorb light in the region of 250–425 nm and show a single and symmetric broadband emission centered at about 470 nm due to the 4f65d–4f7 transitions of Eu2+. The luminescence intensity increases with the SiC content and reaches its maximum at x = 0.20. The critical quenching concentration of Eu2+ in the (SiC)0.20–(AlN)0.80:yEu2+ phosphor is about y = 0.006. The composition-optimized (SiC)0.20–(AlN)0.80:0.006Eu2+ phosphor shows a small thermal quenching, retaining the luminance of 91.1% at 150 °C. The CIE coordinates were measured as (0.135, 0.167) with high color purity. The above results indicate that (SiC)x–(AlN)1−x:yEu2+ is a promising candidate as a blue-emitting ultraviolet convertible phosphor for white LEDs, and the combustion reaction route is expected to be applicable to the synthesis of other kinds of nitride phosphors.