Concentration quenching in Ce ³⁺-doped LED phosphors

In this report, we discuss the relationship between Ce ³⁺ luminescence versus concentration in Sr ₃AlO ₄F-based phosphors with respect to their nature and the impact on the excitation, emission, and quenching of these phosphors. At higher concentrations, Ce ³⁺ centers with lower energy 4f ¹→5d ¹ absorption bands and stronger thermal quenching are present. The presence of lower efficiency, low energy Ce ³⁺ centers leads to quenching at room and elevated temperatures at higher Ce ³⁺ concentrations. Our initial analysis indicates that these lower energy centers arise from O ^2- substitution of F ^- in these hosts.