A luminescence spectroscopy study of scintillation crystals SrI2 doped with Eu2+

We report experimental study of luminescent properties of modern scintillation material SrI2:Eu2+ carried out over the temperature range from 9 to 450 K by the means of the ultraviolet and vacuum ultraviolet spectroscopy with a time resolution. Photoluminescence of the Eu2+ ions at 2.85 eV was studied under both the intracenter and interband excitations, including an X-ray excitation. The bandgap of the SrI2 crystal has been estimated on the basis of the obtained results. In the temperature range below 100 K the intrinsic luminescence at 3.4 eV was revealed and this emission band was assigned by its properties to the luminescence of self-trapped anionic excitons in SrI2. The pronounced manifestation of the effect of multiplication of electronic excitations was revealed in the energy range above 2Eg.

► We studied luminescence of SrI2:Eu2+ under excitation with UV, VUV, X-rays.
► The bandgap value was estimated as Eg = 5.7 − 5.8 eV.
► The effect of multiplication of electronic excitations was revealed above 2Eg.
► The 2.85 eV emission band was assigned to d→f transitions of Eu2+.
► The luminescence of self-trapped anionic excitons at 3.4 eV was revealed.
► The 2.2 eV emission band was assigned to appearance of crystal hydrates.