Developing a new persistent luminescence material by introducing cation defects

Abstract

Crystal defects significantly impact luminescent properties, particularly for thermal stability and persistent luminescence (PersL). In this study, a new Ce3+ doped phosphor K3GdSi2O7:xCe3+ is synthesized at a high temperature of 1200 °C with interesting PersL. Based on electron paramagnetic resonance spectra, there is a cation defect in the K3GdSi2O7:xCe3+ phosphor. We deduce that the principal source of defect is K+ vacancy mainly because of the aliovalent substitution of K+ by Ce3+. The K+ forms a number of trap energy levels, which can be confirmed by a thermoluminescence study. Within the range of 10–225 K, the intensity of the emission increases with the increase in temperature, due to the energy release of deep-level traps. At room temperature, K3GdSi2O7:0.05Ce3+ shows PersL of about 728 s induced by shallow-level traps. We think that K3GdSi2O7:0.05Ce3+ is a potential PersL material for applications in fields of emergency illumination, traffic indication, anti-counterfeiting, and information security.