Structure and luminescence properties study of Eu 2+ doped Ca 2 Al 2−x Si 1+x O 7−x N x phosphors based on size-mismatch model

Eu 2+ doped Ca 2 Al 2−x Si 1+x O 7−x N x (CASON) green-emitting phosphors were prepared by the high temperature solid state reaction method. The crystal structure and luminescence properties were systematically investigated by X-ray powder diffraction and fluorescence spectrophotometer. It was found that Al-O bond could be substituted by Si-N bond in the Ca 2 Al 2 SiO 7 lattice with the maximum solubility of about x =0.4. Under the excitation of 360nm, the photoluminescence (PL) spectra of Ca 2 Al 2−x Si 1+x O 7−x N x : Eu 2+ phosphors presents a blue shift with the increase of x values. The mechanism was discussed in detail by Size-Mismatch model.