An investigation of Eu2+-doped CaAlSiN3 fabricated by an alloy-nitridation method

We have synthesized CaAlSiN3:Eu phosphors through an alloy-nitridation method with stable alloys as main starting materials, and investigated their crystal structures and photoluminescence properties in three aspects as below: (1) different Eu concentrations; (2) different Eu dopants; (3) different Al/Si molar ratios. The lattice volume calculated by using Rietveld refinement on the base of XRD analysis, decreases with oxygen incorporating, increases with the Al/Si ratios, and shows a limited expansion with the raise of Eu concentrations in CaAlSiN3:Eu crystal lattice. The concentration quenching and the shifts of emission bands are investigated and discussed in details. The different lattice volumes deriving from corresponding compositions have an important effect on photoluminescence properties. This work provides some methods to tune the emission wavelengths of CaAlSiN3:Eu phosphors.