Luminescence properties of CaAlSiN3:Eu2+ phosphor prepared by direct-nitriding method using fine metal hydride powders

• High quality of CaAlSiN3:Eu2+ were synthesized by using metal hydride powders.
• The resultant phosphor was well crystallized and showed a broad excitation band.
• The resultant phosphor shows low thermal quenching effect at 150 °C.

Nitride phosphor, CaAlSiN3:Eu2+, was efficiently synthesized without any impurity phase by the direct-nitriding method using metal hydride fine powders of (Ca0.97Eu0.03)AlSiHx and/or CaH2 in a particle size range below 20 μm as starting materials under atmospheric pressure heating conditions in a stream of N2 gas. High-quality powders of CaAlSiN3:Eu2+(3 at%) phosphor were obtained from such metal hydride powder mixed with a large excess amount of CaH2 powder (>30 wt%) as a flux and gave an intense red emission band peaking at 650 nm under the excitation of 450 nm, of which the relative integrated emission intensity was about 110% versus that of a commercially-available YAG:Ce3+ (P46-Y3) standard phosphor. Also, the thermal quenching effect was as low as the CaAlSiN3:Eu2+ phosphors prepared by the other methods (−6% at 150 °C), so that this direct-nitriding method was noted as one of excellent procedures to produce the high-quality nitride phosphors for white-LED illumination lamps.