Trap properties of a novel UV-A persistent phosphor Sr3MgSi2O8:Ce3+

For the last few decades, there has been extensive research on the materials that persist to emit optical radiation long after any type of charging has stopped. Most of the established persistent luminescence (PersL) materials emit light in the visible part of the spectrum; however, in recent years, there has been a growing interest in UV-emitting persistent phosphors in recent years. These materials have been tested for various applications, such as photocatalysis, sterilization, and anti-counterfeiting, among others. Here, we report on the X-ray and UV-activated UV-A long PersL of Ce3+-doped Sr3MgSi2O8 material. We prepared samples with varied Ce3+ concentrations using solid–state reaction synthesis in an ambient atmosphere and conducted a thorough investigation using photoluminescence (PL), electron paramagnetic resonance (EPR), and thermally stimulated luminescence (TSL) spectroscopy methods. Our experiments show that the PersL signal of Ce3+ in the 300–450 nm range can be detected for at least 16 h when samples are irradiated with X-rays or UV. The TSL analysis reveals multiple discrete charge traps in the material with activation energies between 0.5 and 1.7 eV. Further EPR measurements confirm the presence of four paramagnetic centers. The thermal stability of these centers was analyzed, and it is established that one of these centers (g1 = 2.0056, g2 = 1.9981, and g3 = 1.9926) gradually decays at room temperature, which is correlated with the PersL processes.