An efficient co-doping of Eu and Er in CaAl2O4 aluminate phosphor

CaAl₂O₄:Eu²⁺ co-doped with varying concentrations of Er³⁺ was prepared by solid-state reaction method. Prepared materials with 1 mol% Eu²⁺ and 2-10 mol% of Er³⁺ were investigated for their photoluminescence properties. Phase, morphology and crystalline structure were investigated by powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Broad band UV-excited luminescence was observed for CaAl₂O₄:Eu²⁺, Er³⁺ in the blue region (λ_max=440 nm) due to transitions from 4f⁶5d¹ to the 4f⁷ configuration of the Eu²⁺ ion. The Er³⁺ ion co-doping generates deep traps, which results in longer decay time for phosphorescence.