Carbothermal synthesis of CaAlSiN3:Eu2+ red-emitting phosphors and the photoluminescent properties

In this work, red-emitting nitride phosphor, CaAlSiN 3 :Eu 2+ , was synthesized successfully by carbothermal method using CaH 2 , AlN, Si 3 N 4 , Eu 2 O 3 and graphite powder under the condition of atmospheric pressure with a moderate temperature of 1550 °C for 6 h. In particular, graphite powder was employed as efficient and robust reducing agent in an optimal C/O mol ratio of 0.86. The obtained CaAlSiN 3 :Eu 2+ phosphors were well crystallized and showed an intense red emission band with peaks in the range of 642–675 nm dependent on the Eu 2+ doping concentration. Excellent thermal stability for as-synthesized Ca 1−x AlSiN 3 :xEu 2+ (x = 0.02–0.10) phosphors with absolute quantum efficiency about 20 % were demonstrated. These results presented here indicated the promising prospect for this economic and facile carbothermal synthesis route in preparing CaAlSiN 3 :Eu 2+ phosphors , and the phosphors are highly promising candidates for warm white LEDs.