Trap-Engineering the Persistent Luminescence of Ca3Ga4O9:Tb3+ via Al3+ Substitution for Optical Data Storage

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 Ca3Ga4O9:Tb3+ by Al3+ substitution through trap engineering and demonstrated their potential. Specifically, the photoluminescence of the Ca-2.985(Ga1-y%Aly%)(4)O-9:0.5%Tb3+ of Tb3+ is first investigated due to its different occupancies of Ca2+. 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(Ga1-y%Aly%)(4)O-9:0.5%Tb3+ with bluish-green emissions have been observed. The Ca-2.985(Ga1-y%Aly%)(4)O-9:0.5%Tb3+ 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 Ca3-x%(Ga1-y%Aly%)(4)O-9:x%Tb3+ can be manipulated by Tb3+ doping and Al3+ 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 Al3+ substitution is an effective method for tuning PersL and OSL properties of Ca-2.985(Ga1-y%Aly%)(4)O-9:0.5%Tb3+ for ODS.