Improvement of thermal damage resistance of SrAl2O4:Eu2+, Dy3+ persistent phosphor by a low temperature pre-annealing and its mechanism

SrAl2O4:Eu2+, Dy3+ as an excellent persistent phosphor has been widely applied in many fields. However, the high temperature induced thermal failure has always been a bottleneck problem restricting its long-term development. In this study, a simple pre-annealing method was utilized to improve the thermal damage resistance ability of SrAl2O4:Eu2+, Dy3+ persistent phosphors. After annealing at 900 °C, the afterglow duration time of the phosphor pre-annealed at 400 °C reached 233 min, which was twice longer than that of the phosphor without pre-annealing. An extrinsic vacancy defect migration theory at an elevated temperature was proposed to explain the interesting phenomenon. This study introduced a path to enhance the thermal stability of SrAl2O4:Eu2+, Dy3+ persistent phosphors and provided a thought to design persistent luminescence materials with desired thermal stability.