Optical properties of SrF2 and SrF2:Ce3+ crystals codoped with In3+

Abstract

The paper presents the results of a comprehensive study of effects that In³⁺ ion impurities have on the optical properties of SrF₂ and SrF₂:Ce³⁺ crystals. The investigations were carried out both by optical spectroscopy methods and ab initio quantum chemical calculations. To estimate the effect of indium impurities on the optical band gap of the crystals, the DFT calculations were performed for SrF₂ crystals doped with different concentrations of In³⁺ ions. The study of SrF₂ crystals co-doped with Ce and In ions reveals the highly effective role of indium ions in reducing the electron trapping efficiency in the processes of excitation transfer to an activator. This improvement is associated with some change in the band gap of the crystals caused by indium doping, which is confirmed by both theoretical and experimental results.