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

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.