Trap‐Engineering the Persistent Luminescence of Ca ₃ Ga ₄ O ₉ :Tb ³⁺ via Al ³⁺ Substitution for Optical Data Storage

Abstract Optically stimulated luminescence (OSL) materials hold great potential for optical data storage (ODS) and anticounterfeiting applications. Nevertheless, the scarcity of suitable luminescent materials with deep‐level traps remains a significant obstacle. Herein, a host substation strategy have been employed to tune the persistent luminescence (PersL) and OSL properties of Ca ₃ Ga ₄ O ₉ :Tb ³⁺ by Al ³⁺ substitution through trap engineering and demonstrated their potential. Specifically, the photoluminescence of the Ca _2.985 (Ga _1‐y% Al _y% ) ₄ O ₉ :0.5%Tb ³⁺ of Tb ³⁺ is first investigated due to its different occupancies of Ca ²⁺ . The influence of host substitution on the crystal structure, trap depth, trap density, PersL, and OSL properties have further investigated. A series of strong PersL and OSL peaks from the Ca _2.985 (Ga _1‐y% Al _y% ) ₄ O ₉ :0.5%Tb ³⁺ with bluish‐green emissions have been observed. The Ca _2.985 (Ga _1‐y% Al _y% ) ₄ O ₉ :0.5%Tb ³⁺ have shown controllable photon release upon thermal and optical stimuli, enhancing their performance for ODS. Thermally stimulated luminescence suggests that vacancy and defect concentrations inside the Ca _3‐x% (Ga _1‐y% Al _y% ) ₄ O ₉ :x%Tb ³⁺ can be manipulated by Tb ³⁺ doping and Al ³⁺ substitution, which ultimately leads to the formation of deep traps and a broad distribution of traps with increased deep trap concentration. The work demonstrates that trap engineering through Al ³ ⁺ substitution is an effective method for tuning PersL and OSL properties of Ca _2.985 (Ga _1‐y% Al _y% ) ₄ O ₉ :0.5%Tb ³⁺ for ODS.