Effective suppression of AlN impurity in synthesis of CaAlSiN3:Eu2+ phosphors under condition of atmospheric pressure

Two strategies, deviation of stoichiometry and addition of flux, were employed in this work to suppress the emergence of AlN impurity in the synthesis of CaAlSiN3:Eu2+ phosphors under condition of atmospheric pressure. The influence of Al atoms deviation from ideal stoichiometry and SrF2 flux addition on the suppression of AlN impurity and their resultant photoluminescence properties are investigated for CaAlSiN3:Eu2+ phosphors. For a special Eu2+ doping concentration (0.02 mol), AlN impurity was suppressed effectively when Al element deviation is 0.2 mol (CaAl0.8SiN3) and the SrF2 flux addition is 7 wt% during preparation of CaAlSiN3:Eu2+ phosphors, respectively. The luminescent properties of CaAlSiN3:Eu2+ phosphors are found to be enhanced significantly owing to the suppression of AlN impurity. In addition, the suppression mechanisms of AlN impurity in atmospheric pressure-synthesized CaAlSiN3:Eu2+ phosphors are discussed. These results indicate the promising prospect for our proposed strategies in preparing high performance CaAlSiN3:Eu2+ phosphors under the condition of atmospheric pressure.