Photo-induced phase segregation in mixed-halide perovskites for secure information security

Metal halide perovskites are considered an important class of semiconductors in optoelectronics owing to their excellent optoelectronic properties. Unfortunately, phase separation in mixed-halide systems is often identified as a critical defect, leading to compromised stability and reduced luminescence efficiency. Conventional research has primarily focused on suppressing this phenomenon, whereas this work innovatively exploits the spatial randomness of the bromine/iodine ratio and the photo-triggered phase separation defect in mixed-halide perovskites, transforming them into advanced functionalities for anti-counterfeiting and information encryption. Leveraging the unpredictable and reversible red-shift behavior observed by the samples under light irradiation, optical physical unclonable function labels that break through the static limitations have been constructed. Additionally, self-erasing image encryption is achieved through controlled photodegradation in I-rich regions. This work provides a technical pathway for the development of intelligent photonic cryptographic chips and high-security anti-counterfeiting technologies.