Smartphone-Activated Anti-Counterfeiting via HDPE/Poly(3-bromothiophene)-Encapsulated FAPbBr₃ Perovskite Nanocomposites

In this study, a novel composite material was developed by embedding poly(3-bromothiophene)-encapsulated FAPbBr₃ perovskite (Pv@PTBr) within a high-density polyethylene (HDPE) matrix for advanced anti-counterfeiting applications. The encapsulation of FAPbBr₃ with poly(3-bromothiophene) (PTBr) significantly enhances environmental stability by preventing degradation from oxygen and moisture while maintaining strong photoluminescence. The resulting HDPE/Pv@PTBr films exhibit bright green emission under UV illumination, tunable through the concentration and distribution of the active phase. Building on this functionality, a secure bilayered QR code system was fabricated using the composite. The first optical layer provides fluorescence-based security, remaining inconspicuous under normal lighting but highly scannable when activated by UV-A or a torch source. The second electronic layer integrates a material-specific encrypted password, derived from the composite’s peak electrical conductivity (0.058 S at 100 kHz), linked to a secure URL for authentication. This dual-layer mechanism ensures that code readability and verification occur only under specific physical and optical conditions, preventing digital duplication or tampering. The unique combination of photonic and electrical responses enables direct fabrication of functional, durable, and light-activated QR codes within the HDPE matrix, offering a practical, smartphone-accessible, and scalable solution for secure, smart packaging applications.