Excitation-dependent ultraviolet-visible persistent luminescence and charge trapping in Ca₂Al₂SiO₇:Ce³⁺: Ce³⁺

Ultraviolet (UV) persistent luminescence (PersL) materials are notable for their diverse applications, including sterilization, biomedical uses, and anti-counterfeiting markers. In this work, we report an in-depth investigation of luminescence, defect formation, and UV-visible PersL properties of Ce³⁺-activated Ca₂Al₂SiO₇. Structural characterisation confirms successful incorporation of Ce³⁺ into the material. PersL excitation and electron paramagnetic resonance (EPR) spectra measurements suggest photoionisation of Ce³⁺ to Ce⁴⁺. Thermally stimulated luminescence (TSL) spectroscopy analyses reveal that the activation energies of UV-induced charge traps are in the 0.85-1.2 eV range. The PersL of Ca₂Al₂SiO₇: Ce³⁺ can be detected for longer than 48 h above the 5⋅10⁻⁴ mW/m²/sr radiance threshold. Moreover, its emission reaches a power density of 12.55 mW/m² at 10 s after UV excitation, demonstrating both a high initial signal intensity and slow decay. These results reveal crucial information about achieving optimal performance of Ca₂Al₂SiO₇: Ce³⁺ as an efficient UV-visible persistent phosphor