The luminescence of bismuth and manganese in LaMgB5O10

The luminescences of Bi³⁺ and Mn²⁺ in LaMgB₅O₁₀ are reported. The emission of the Bi₃₊ ion shows a small Stokes shift and is situated in the ultraviolet. From the decay times the ³P₀ and ³P₁ levels appear to be mixed. At 4.2 K no energy transfer between Bi³⁺ ions occurs, but at room temperature the critical distance for this energy transfer amounts to some 25 Å. This knowledge is used to explain energy transfer between Bi³⁺ and Tb³⁺ in LaMgB₅O₁₀, which is compared with that between Ce³⁺ and Tb³⁺ in the same lattice. The Mn²⁺ ion shows a red emission in LaMgB₅O₁₀. The Bi₃₊ ion acts as a sensitizer for this emission, whereas the Ce³⁺ ion does not.