Influence of temperature on the 4f5d emission of Pr 3+ in SrB 4O 7

Abstract

The temperature-dependent emission spectra of Pr 3+-doped SrB 4O 7 were investigated from 20 to 300 K under vacuum ultraviolet excitation. When the temperature was over 80 K, the interconfigurational 4f 15d 1→4f 2 and intraconfigurational 4f 2→4f 2 emissions could be observed simultaneously. The theoretical model describing thermal equilibrium of the energy levels was applied successfully to the system concerning the lowest-energy 4f5d state and 1S 0 state of SrB 4O 7:Pr 3+. In addition, the decay curves of Pr 3+ emissions from 300 to 600 K were also measured. The decay times of 4f5d emission and 1S 0 emission were same for a certain temperature and became faster with increased temperatures, which further identified the validity of the model applied to the system. This paper clarified the nature of unusual temperature dependence of the emission spectra of Pr 3+ in SrB 4O 7.