Synthesis of a CaAl2O4:Eu2+, Dy3+ Phosphor by the Polymer Slurry Method and Its Application in Anticounterfeiting

CaAl2O4:Eu2+, Dy3+ long-afterglow-luminescence materials were prepared by a high-temperature solid-state reaction assisted by the polymer slurry method (HTSSR-PS). X-ray diffraction and scanning electron microscopy were employed to observe the crystal structure and microstructure of CaAl2O4:Eu2+, Dy3+ phosphors. In addition, density functional theory calculations were utilized to investigate the electronic and crystal structures of CaAl2O4. Fluorescence spectra and afterglow decay curves characterized luminescence properties. Thermoluminescence curves characterized the optical storage performance. CaAl2O4:Eu2+, Dy3+ sintered at 1300 °C exhibited the highest crystallinity and the best afterglow performance. Compared to the conventional HTSSR method, the calcination temperature was significantly lower, and the performance was improved. The method was simple, with lower energy consumption, and it was more suitable for large-scale production. In addition, the application of CaAl2O4:Eu2+, Dy3+ in dynamic anticounterfeiting was demonstrated by exploiting a unique afterglow property.