Luminescence of rare-earth activated Y2SiO5

Coactivation of Y2SiO5 with the electron trap Eu3+ and the hole traps Pr3+, Tb3+ or Dy3+ results in cathodoluminescence for the couple Eu3+/Tb3+ in an efficient energy transfer Tb3+→Eu3+ owing to the strong binding potential for carriers of Eu3+ and the high hole-capture cross section of Tb3+. However, for the combinations Eu3+/Pr3+ and Eu3+/Dy3+, the hole-capture cross section of Pr3+ or Dy3+ is reduced. Furthermore, the energy transfer to Eu3+ is hampered by the presence of lattice defects. Because of the differences in the transfer mechanisms for photo- and cathodoluminescence, an energy transfer Tb3+→Eu3+ is present in photoluminescence only for high Tb3+ concentrations, as a consequence of the mobility of the excitation energy in the Tb3+ sublattice. (orig.)