The nature of Bi³⁺ luminescence in the double perovskite, La₂LiSbO₆

We have examined the luminescence of Bi³⁺ (6s²) in La₂LiSbO₆ which is a monoclinic distorted double (ordered) perovskite. The optical properties of Bi³⁺ can be rationalized in terms of the localized ³P_0,1→¹S₀ emission transition. There is no evidence for emission from the D-state despite the presence of Sb⁵⁺ with the 4d¹⁰5s⁰ electronic configuration. Band structure calculations were performed to determine the composition of the conduction band. A comparative study of Bi³⁺ luminescence in several perovskites containing cations with nd⁰ and nd¹⁰ electronic configuration show that composition of the conduction band makes an important contribution to the occurrence or lack thereof of the D-state emission. A comparative study of the temperature dependence of the Bi³⁺ luminescence efficiency in La₂LiSbO₆ and CaZrO₃ leads to the tentative conclusion that thermally activated crossover from the Bi³⁺ 6s¹6p¹ excited state to the 6s² ground state is responsible for the quenching of Bi³⁺ luminescence in these perovskites.