Multi-stimuli geminate encryption based on triphenylethylene for advanced anti-counterfeiting

The development of multi-stimulus responsive materials, especially those capable of displaying multiple patterns within the same region, can significantly enhance information capacity and security. This study presents a novel strategy for gemini-information output activated by temperature and optical stimuli. We synthesized three triphenylethylene derivatives, designated S-Br, D-Br, and T-Br, with aggregation-induced enhanced emission characteristics by varying the number of bromine atom substituents. Notably, thermal activation can induce photochromic behavior of T-Br and achieve wavelength modulation of fluorescence by switching the aggregation state from crystalline to molten amorphous. In contrast, it only enhances the photochromic contrast and fluorescence quenching of S-Br and D-Br. By leveraging their distinct photophysical and photochemical properties, we developed a multi-responsive gemini-encrypted paper. This paper reveals two entirely different information in photochromic and photofluorochromic states when sequentially heated to the melting points of S-Br, D-Br, and T-Br. This gemini-information output triggered by temperature and optical stimuli offers a novel approach to encryption and anti-counterfeiting, and demonstrate enormous potential for enhancing the level of anti-counterfeiting.