Atmospheric pressure preparation of red-emitting CaAlSiN3:Eu2+ phosphors with variable fluxes and their photoluminescence properties

A red-emitting Eu2+ activated CaAlSiN3 phosphor was successfully prepared via an atmospheric pressure solid-state reaction method with the aid of variable fluxes, namely SrF2, NH4F, BaF2, NaF, AlF3, CaF2 and NH4Cl. The experimental results showed that the addition of SrF2 flux effectively reduced the formation temperature of CaAlSiN3: Eu2+ about 100 °C, improved the morphology of CaAlSiN3: Eu2+ and suppressed the appearance of AlN impurity phase, suggesting that SrF2 flux modifies the formation mechanism of CaAlSiN3: Eu2+. The phosphor of the CaAlSiN3:Eu2+ produced with 4 wt% SrF2 flux had an enhanced emission intensity, which was a result of the high crystallinity, the absence of AlN secondary phases, and the clean surfaces of the particles in the final product.