Advanced multicolor dynamic fluorescence anti-counterfeiting and encryption strategy based on light-induced reversible perovskite lattice distortion

Time-dynamic fluorescence encryption and anti-counterfeiting technology have garnered significant attention in the high-end information security field. However, developing tunable multicolor solid-state photoluminescent systems that are low-cost, easy to manufacture, scalable, and convenient to verify remains a considerable challenge. In this study, we finely tuned the luminescence behavior of CsCdCl3 all-inorganic perovskite crystals using a halogen doping strategy, resulting in reversible lattice distortion under UV light and endowing them with photoactivated luminescence properties to produce dynamic fluorescence. Upon the introduction of Br-, the optical properties of CsCdCl3 changed significantly, with the fluorescence emission color shifting from orange to white-green under UV irradiation. By adjusting the Br- doping ratio and UV irradiation intensity, the fluorescence color change time of CsCdCl3 can be controlled. Multiple cycle light exposure tests demonstrated that the luminescence properties of CsCdCl3 remained identical to the initial state, indicating high stability in response to UV stimulation. Consequently, we successfully realized advanced anti-counterfeiting and 4D code encryption modes based on dynamic fluorescence. The introduction of a time variable imparts extremely high security to these strategies. This work provides an exciting approach for designing information encryption materials with higher security requirements and offers a promising high-sensitivity UV detection material.