Color‐Tunable Persistent Luminescence in Eu ²⁺ ,Dy ³⁺ ,B ³⁺ Co‐Doped Sr ₄ Al ₁₄ O ₂₅ and SrAl ₂ O ₄ Strontium Aluminates Ceramics for Anti‐Counterfeiting Applications

Abstract Persistent luminescent (PersL) materials have garnered significant attention for applications in signaling, bioimaging, and anti‐counterfeiting due to their long‐lasting emission after excitation stoppage. Achieving both extended afterglow durations and stable luminescence remains challenging. This study investigates the effects of crystalline composition on the PersL properties of two polycrystalline ceramics namely Sr ₄ Al ₁₄ O ₂₅ :Eu ²⁺ , Dy ³⁺ , B ³⁺ (blue‐emitting, SAO‐B) and SrAl ₂ O ₄ :Eu ²⁺ , Dy ³⁺ ,B ³⁺ (green‐emitting, SAO‐G). Through various characterization techniques such as thermoluminescence (TL), radioluminescence (RL), and photoluminescence (PL) as well as persistent luminescence (PersL) excited by different sources such as X‐ray, UV and visible lights, one demonstrates that SAO‐B exhibits deeper traps which offer much longer afterglow duration than SAO‐G, whereas SAO‐G provides higher initial emission intensity and higher quantum yield. By leveraging structural PersL properties in Eu ²⁺ , Dy ³⁺ , B ³⁺ co‐doped compounds, color‐tunable emission is observed. This allows for the proposal of various novel “temperature resolved” and “time resolved” anti‐counterfeiting patterns, driven by the differing decay times of these aluminates. This establishes a streamlined, scalable approach to persistent phosphor design, advancing applications in security, safety lighting, and dynamic displays.