Exploration and optimization of Dy codoping in polycrystalline CaAl2O4:Eu

Calcium aluminate, CaAl2O4 is efficient phosphor when doped with suitable activator ion. CaAl2O4 codoped with 1 mol% Eu (fixed) and varying Dy concentrations (1–10 mol%) were prepared by solid-state synthesis method. Crystalline phase, morphology and structure were investigated by powder XRD and transmission electron microscopy (TEM) techniques. Prepared compositions were investigated for photoluminescence characteristics. Intense luminescence was observed for CaAl2O4:Eu2+, Dy3+ in the blue region (λmax = 440 nm). Deep trap levels are generated by Dy3+ ions, which result in long persistent phosphorescence. Highest PL intensity was observed for the codoping combination of 1 mol% Eu and 5 mol% Dy.