Simultaneous excitation of Ce3+ and Eu3+ ions in Tb3Al5O12

Y3Al5O12:Ce3+ (YAG:Ce) and Tb3Al5O12:Ce3+ (TAG:Ce) both show the typical Ce3+ ion luminescence of the allowed Ce3+ d-f transition. Eu3+ codoping, however, reveals different results for both matrices: in YAG:Ce,Eu, only the luminescence of the Ce3+ ion occurs by excitation within the Ce3+ absorption bands. Here, the Eu3+ luminescence cannot be sensitized by the Ce3+ ion. But in TAG:Ce,Eu, both Ce3+ and Eu3+ luminescence are measured at several excitation wavelengths: an excitation within the Tb-sublattice results in both Ce3+ and Eu3+ luminescence, which is not surprising as an energy transfer from Tb3+ to Ce3+ and Eu3+ is well known in literature. In addition, an excitation in the lowest 5d level of Ce3+ delivers Eu3+ luminescence at room temperature. This means that the Ce3+ ion can be used as a sensitizer in the TAG lattice that transfers its energy via the Tb sublattice to the activator Eu3+. (C) 2003 Elsevier Ltd. All rights reserved.