5d–4f and 4f–4f emissions in Ln-doped sesquioxide ceramics

In this study, various lanthanide and mixed lanthanide oxides (Ln2O3 with Ln = La, Lu, Lu0.5Gd0.5) powders have been synthesized by a coprecipitation method. The luminescence properties and/or the quenching mechanisms of different dopants (europium, cerium, praseodymium) have been studied. Luminescence mechanisms of Ce:Ln2O3 and Pr:Ln2O3, are closely related to the 5d and 4f energy levels positions of the dopant versus materials bandgap and crossing effect between dopant energy levels. Energy level positions have been analyzed through optical spectroscopy and their effect on the luminescence is presented. Eu:Lu2O3 and Eu:LuGdO3 have also been prepared as transparent ceramics and radioluminescence properties are presented.

Research highlights
► We performed synthesis of transparent rare earth doped mixed oxides.
► We described criteria for Pr (1D2 level) or Pr (3P0 level) emission.
► Energy level positions for the host and the C2 and S6 sites.
► Description of how energy level positions influence the lanthanides emission.