Influence of additional Eu3+ coactivator on the luminescence properties of Tb3Al5O12:Ce3+, Eu3+

The luminescence properties of doubly activated terbium aluminium garnet samples were investigated in the present study. Commercial Tb3Al5O12:Ce3+ (TAG:Ce) shows the typical Ce3+ ion luminescence of the allowed Ce3+ d–f transition. Eu3+ co-doping, however, reveals interesting results. In TAG:Ce, Eu, both Ce3+ and Eu3+ luminescence was measured at different Ce and Eu activator concentrations. The Ce3+ ion can be used as a sensitizer in the TAG lattice that transfers its energy directly or via the Tb sublattice to the activator Eu3+. The energy-level diagram was proposed to explain the luminescence mechanism. Application of TAG:Ce, Eu with improved chromaticity coordinates CIE (Commission Internationale de l’Eclairage) and color rendering index (CRI) in light emitting diodes (LEDs) is demonstrated.