Luminescence Spectra of YGG:RE³⁺,Bi³⁺ RE= Eu and Tb) and Energy Transfer from Bi³⁺ to RE³⁺

We investigate the luminescence properties of Bi³⁺ and RE³⁺ (RE = Tb or Eu) in a Y₃Ga₅O₁₂ (YGG) host system. The additional doping of Bi³⁺ can enhance the luminescence of Tb³⁺ or Eu³⁺ in this host. Energy transfer from Bi³⁺ to Tb³⁺ and Eu³⁺ is observed and the mechanism of energy transfer is investigated. Mechanism of energy transfer can be explained as electric multipole interaction since the Bi³⁺ emission band and Tb³⁺ or Eu³⁺ excitation band overlaps and the Bi³⁺ emission intensity decreases while the intensity of Tb³⁺ or Eu³⁺ increases with the increase of Tb³⁺ or Eu³⁺ concentration.
Therefore, Bi³⁺ ion is a kind of efficient sensitizer to the Tb³⁺ and Eu³⁺ activators in the Y₃Ga₅O₁₂ host.