Luminescent properties of (La,Lu,Gd)3(Al,Sc,Ga)5O12:Ce mixed garnets under synchrotron radiation excitation

Abstract

The phosphors based on the single crystalline films (SCFs) of Ce-doped mixed garnets with the La1.5Lu1.5Sc2Al3O12:Ce, La1.5Lu1.5Sc2Ga3O12:Ce and Gd1.75Lu1.25Sc2Al3O12:Ce nominal content were crystallized by the liquid phase epitaxy (LPE) method onto Gd3Ga5O12 (GGG) substrates from melt-solutions based on the PbO-B2O3 flux. The luminescent properties SCFs of these mixed garnets were investigated under e-beam and synchrotrons radiation (SR) excitation and compared with the properties of LuAG:Ce and YAG:Ce counterparts. The basic optical characteristics of the La1.5Lu1.5Sc2 Al3O12:Ce, La1.5Lu1.5Sc2Ga3O12:Ce and Gd1.75Lu1.25Sc2 Al3O12:Ce garnets, e. g., the energy of formation of excitons bound with the Ce3+ ions and the decay time of the Ce3+ luminescence, were determined using excitation by SR with an energy of 3.7–25 eV in the range of the fundamental absorption edge of garnet hosts. We have also found the significantly larger influence of Pb2+ flux related impurity on the LY of the Ce3+ luminescence in SCFs of the mentioned mixed garnets, grown onto GGG substrates, in comparison with the YAG:Ce and LuAG:Ce SCFs analogues, grown onto YAG substrates. The best light yield (LY) (7–9% in comparison with YAG:Ce SCFs) under excitation by α–particles of Pu239 source is observed in the La1.5Lu1.5Sc2Al3O12:Ce SCFs.