Ultraviolet-C persistent luminescence and defect properties in Ca2Al2SiO7: Pr3+

In recent years, significant attention has been focused on the study of materials with ultraviolet (UV) persistent luminescence (PersL) due to their prospective application possibilities. Although novel UV persistent phosphors are being developed, reports on defect properties and PersL mechanisms are limited. In this study, the incorporation of Pr3+ ions in Ca2Al2SiO7 is analyzed using X-ray diffraction (XRD) and X-ray absorption techniques, whereas PersL properties are characterized by photoluminescence (PL), thermostimulated luminescence (TSL) and electron paramagnetic resonance (EPR) methods. Analysis of the Pr L3-edge X-ray absorption spectra suggests that praseodymium atoms substitute for calcium atoms. The UV-C PersL of the host results from thermally assisted recombination of charge carriers with trap depths within the 0.50-0.87 eV range. Moreover, a partial correlation of PersL and TSL with the decay of X-ray-induced paramagnetic centers was observed. This study expands the knowledge base on the structure of Ca2Al2SiO7 and establishes the optimal Pr3+ concentration for efficient UV-C PersL.