Effects of additional Ce³⁺ doping on the luminescence of Li ₂ SrSiO₄: Eu²⁺ yellow phosphor

Additional Ce³⁺ doping improves the luminescence of Li ₂ SrSiO₄: Eu²⁺, a yellow phosphor for ultraviolet or blue light-emitting diodes. By examining the photoluminescence of Li₂ SrSiO₄: Eu²⁺, Li₂ SrSiO ₄: Ce³⁺, and Li₂ SrSiO₄: Ce ³⁺, Eu²⁺, it was confirmed that the energy transfer from Ce³⁺ to Eu²⁺ ions contributes little to the enhanced luminescence of Li₂ SrSiO₄: Ce³⁺, Eu ²⁺. Alternatively, we suggested that Ce³⁺ ions could stabilize the Li vacancies, inhibit the oxidization of Eu²⁺ to Eu³⁺, and consequently increase emission intensity, based on the characterizations with decay time and synchrotron light source x-ray absorption measurements. The proposed argument was validated with first principle calculations of the defect formation energies.