The Luminescence of Several Activators in SrLa₂BeO₅, a Partially Disordered Compound

The luminescence of nominally pure Eu³⁺, Tb³⁺, Sm³⁺, Ce³⁺, Pb²⁺, and Bi³⁺‐activated are reported and discussed. Comparisons with are made. The host lattice emission is ascribed to self‐trapped excitons on the gen ions. The trivalent activators show two luminescent centers, the Pb²⁺ only one. This agrees with the crystal structure data. The two Eu³⁺ centers show very different luminescence characteristics. The charge transfer bands are at different positions, the emissions are different, the coupling with the Be‐O vibration differs, and the amount of emission is not equal. The Sm³⁺ charge transfer band is at low energy. The 4f‐5d transitions of Tb³⁺ and Ce³⁺ are also at low energy, resulting, for example, in a green Ce³⁺ emission. Between the two Bi³⁺ centers an efficient energy transfer has been observed.