Photochromism\nand Fluorescence Switch of Furan-Containing\nTetraarylethene Luminogens with Aggregation-Induced Emission for Photocontrolled\nInterface-Involved Applications

Abstract

It is extremely challenging\nto design photocontrolled molecular\nswitches with absorption and fluorescence dual-mode outputs that are\nsuited for a solid surface and interface. Herein, we report a group\nof furan-containing tetraarylethene derivatives with unique photophysical\nbehavior of aggregation-induced emission (AIE) and distinct photochemical\nreaction-triggered photochromic behaviors by combining a photoactive\nfuran or benzofuran group and an AIE-active triphenylethene molecule.\nThe introduction of a furyl or benzofuryl group into the AIE luminogen\nendows the molecules with significant reversible photochromism and\nsolid-state fluorescence. The coloration and decoloration of these\nmolecules can be switched by respective irradiation of UV and visible\nlight in a reversible way, and the photochromic changes are accompanied\nby a switch-on and switch-off of the solid-state fluorescence. It\nis revealed that the photocontrolled cyclization and cycloreversion\nreactions are responsible for the reversible photochromism and fluorescence\nswitching based on experimental data and theoretical analysis. Both\nthe position and conjugation of the introduced photoactive units have\nsignificant influence on the color and strength of the photochromism,\nand the simultaneous occurrence of photoinduced fluorescence change\nin the solid state is perfectly suited for surface-involved applications.\nThe demonstrations of dual-mode signaling in photoswitchable patterning\non a filter paper and anti-counterfeiting of an anti-falsification\npaper strongly highlight the unique advantage of these photochromic\nmolecules with an aggregation-induced emission characteristic in various\npractical applications. This work proposes a general strategy to design\nphotochromic molecules with AIE activity by introducing photoactive\nfunctionals into an AIEgen and demonstrates incomparable advantage\nin dual-mode signaling and multifunctional applications of these molecules.