Optical spectroscopy, thermal quenching and electron–vibrational interaction of the octahedrally coordinated Eu2+ ion in SrAl2B2O7

Abstract The spectroscopic properties of the six-fold (octahedral) coordinated Eu 2+ in SrAl 2 B 2 O 7 have been investigated. Relevant optical parameters such as the Stokes shift, crystal-field splitting, the centroid shift and the red-shift of the Eu 2+ 4f 6 5d 1 electronic configuration have been estimated from the experimental data. Further, the Huang–Rhys factor and the effective phonon energy, which are responsible for electron–vibrational interactions are theoretically estimated for the Eu 2+ ion in SrAl 2 B 2 O 7 . The low quenching temperature of the luminescence is connected with the thermally induced photoionization of the Eu 2+ 4f 6 5d 1 electron. A cross-cutting comparative study of the optical properties of octahedrally coordinated Eu 2+ in SrAl 2 B 2 O 7 and in Cs 2 M 2+ P 2 O 7 (M 2+ =Ca 2+ , Sr 2+ ) is also presented.