Triple-Modal Anti-Counterfeiting Based on CsPbBr₃ Perovskite Quantum Dot/CaAl₂O₄:Eu²⁺, Nd³⁺ Composites with Dual Fluorescence Properties

Advanced fluorescent anticounterfeiting technology has received widespread attention due to the lack of sufficient security of traditional anti-counterfeiting. Hence, there is a great challenge to continuously develop multi-level anti-counterfeiting technology with higher security. Here, we develop a desired fluorescent anticounterfeiting technology based on CsPbBr 3 perovskite quantum dots (PQDs) and CaAl 2 O 4:Eu 2+, Nd 3+ composites with persistent luminescence properties. CsPbBr 3 PQDs can be formed on the surface of the CaAl 2 O 4 host and exhibit an average diameter of around 3.5 nm. The photoluminescence (PL) intensity of CsPbBr 3 PQDs/CaAl 2 O 4 composites is greatly enhanced to 125 times compared to that of pure CsPbBr 3 PQDs, and the desired narrow FWHM of 19 nm is achieved under near-ultraviolet irradiation. Furthermore, highly stable CsPbBr 3 PQDs/CaAl 2 O 4:Eu 2+, Nd 3+ composites with triple-modal (UV, IR, and thermal) fluorescent anti-counterfeiting characteristics were developed and used in fabricating anti-counterfeiting labels through screen-printing technology. The results open up a pathway to enhance the photoluminescence properties and stability of perovskite quantum dots for the advanced fluorescent anticounterfeiting application.