Preparation and spectroscopic studies of the Mg_xSr _1-xAl₂O₄:Eu, Dy (x = 0.05-0.25) persistent phosphors

Mg_xSr_1-xAl₂O₄:Eu, Dy (x = 0.05-0.25) phosphors were prepared by the solid-state reaction method; their excitation and emission spectra corresponding to the transitions between the ground 4f⁷ and excited 4f⁶5d¹ configurations of Eu²⁺ ion were studied. Broad band UV excited luminescence attributed to Eu²⁺ ions was observed around 19,500 cm^-1 (513 nm). From the comparison between the excitation and emission spectra, the crystal field splitting of the Eu²⁺ 5d states and the parameters of electron-vibrational interaction, such as the Huang-Rhys factor, effective phonon energy, and zero-phonon line position for the studied compound were estimated for the first time.