Thermodynamics stability,electronic structures and spectroscopic properties of defects and Ce3+ ions in Y2O3

Thermodynamic properties, electronic structures and spectroscopic properties of defects and Ce³⁺ in Y₂O₃ are studied by using the hybrid density functional theory associated with multi-reference configuration interaction ab-initio calculations. Thermodynamic transition energy levels of the easily generated oxygen vacancies in the host are analyzed according to HSE06-calculated formation energies, which may be conducive to interpretations of the persistent luminescence (PersL) of Y₂O₃-based phosphors. Besides, the locations of impurity states (caused by V_O and Ce³⁺) in energy bands are obtained from derived density of states. Moreover, energies and oscillator strengths of 4f₁ → 5d₁₋₅ transitions of Ce³⁺ ions (at Y1 and Y2 sites) calculated from the CASSCF/CASPT2/RASSI−SO method agree reasonably well with experimental excitation spectra of Y₂O₃: Ce³⁺ phosphors, achieving the assignment of excitation spectra. The presented calculations can be applied to identify luminescent centers in Ce³⁺-doped phosphors and reveals possible native defects and their roles in the PersL of phosphors.