Influence of Ce3+ Concentration on the Thermal Stability and Charge-Trapping Dynamics in the Green Emitting Phosphor CaSc2O4:Ce3+

The influence of the Ce3+ concentration on the excitation and emission characteristics, thermal stability, and charge-trapping–detrapping dynamics, of the green-emitting phosphor Ce3+ doped calcium scandium oxide (CaSc2O4) with very dilute Ce3+ substitutions (0.5, 1.0, and 1.5%), has been investigated using optical spectroscopy techniques. The diffuse reflectance and excitation spectra are found to exhibit a nonsystematic behavior with varying Ce3+ concentration, mainly linked to spectral band-overlap, whereas the emission spectra display only minor changes with varying Ce3+ concentration, suggesting that the local structural coordination of the Ce3+ dopants remains the same for different Ce3+ dopant levels. The major impact of Ce3+ concentration is seen on the thermal quenching temperature, which is found to be as high as T50% ≈ 600 K for the most dilute Ce3+ doping (0.5%), followed by T50% ≈ 530 K for 1.0% doping and T50% ≈ 500 K for 1.5% doping, respectively. The materials are found to display a red-sh...