Blue-/NIR Light-Excited Fluorescence Switch Based on a Carbazole-Dithienylethene-BF 2 bdk Triad

The development of novel solid-state fluorescence switches, particularly triggered by visible light, is of increasing interest for the potential application in optical data storage and super-resolution fluorescence microscopies. In this study, two carbazole-dithienylethene-BF bdk triads and , suspending carbazole and BF bdk moieties on both sides of dithienylethene unit, have been developed. They exhibit blue-/NIR light-controlled photochromism with solvent-dependent characteristics. Moreover, reveals blue-/NIR light-induced reversible fluorescent switching behaviors in toluene, chloroform, poly(methyl methacrylate) (PMMA) film, and powder state, while its analogue in the powder state exhibits no fluorescence due to a strong intermolecular π-π stacking interaction, and the fluorescent switching performance is observed only in toluene and PMMA film. The density functional theory calculations further validate the differences in their optical properties in the solution and powder states.