Energy transfer phenomena in GdMgB5O10

The luminescence of Mn²⁺, Bi³⁺, Ce³⁺ and Tb³⁺ in GdMgB₅O₁₀ and some codoped materials is reported. Energy transfer rates are derived from the experiments. The Bi³⁺ → Gd³⁺ and Gd³⁺ → Bi³⁺ transfer rates are about equal at room temperature. The excitation energy is able to migrate among the Gd³⁺ sublattice. The Ce³⁺ ion is a good sensitizer for this sublattice. By diluting the Gd³⁺ sublattice with La³⁺ ions, the energy migration in Gd³⁺ zig-zag chains was blocked and interchain energy transfer occurred. Very efficient phosphors can be obtained by using Ce³⁺ as a sensitizer, the Gd³⁺ sublattice as an intermediary and Tb³⁺ as an activator.