White-light-driven irreversible photochromism for tamper-evident anti-counterfeiting

Fluorescent photochromic molecules are promising materials for high-security anti-counterfeiting and information encryption. However, their practical applications are hindered by two limitations: their UV-dependent photochromic behavior causes inevitable photobleaching and inconvenient operation, while their reversibility is vulnerable to replication and tampering. Herein, we designed and synthesized three donor-acceptor type diarylethenes by introducing aniline derivatives into 2,3-bis(2-methyl-1-benzothiophene-1,1-dioxide-3-yl)-thiophene. The absorption onset of the open isomers redshifted to ∼480 nm as the electron donating ability of the aniline derivatives increased, and red color closed isomers appeared in both solution and film states along with turn-on red fluorescence upon conventional white-light irradiation. Notably, the cycloreversion process is inhibited with a negligible quantum yield as low as 3.4 × 10^-6 in ethyl acetate due to the high activation energy barrier in the excited state. The applications for tamper-evident anti-counterfeiting, traceability, and information encryption under ambient white light and sunlight illumination are demonstrated. This work establishes a facile molecular design strategy for white-light-responsive fluorescent diarylethenes featuring irreversible photochromism.