Multifunctional Fluorescent Materials with Reversible Mechanochromism and Distinct Photochromism

Abstract It is extremely significant and desirable to integrate the fascinating mechanochromism and photochromism in one simple molecule. Herein, two intriguing cyanostilbene‐containing triphenylamine (TPA)/tetraphenylethylene (TPE) derivatives (Z‐TPA‐MB and Z‐TPE‐MB) are elaborately designed, which not only display excellent aggregation‐induced emission (AIE) properties with high solid‐state fluorescence quantum yields (60.9% and 63.8%) but also exhibit reversible and high contrast mechanochromism and distinct photochromism. The powders of Z‐TPA‐MB and Z‐TPE‐MB both exhibit large red‐shift under mechanical stimulation based on the highly twisted conformation and the resulting loose packing mode, accompanied by significant changes in apparent and fluorescent colors. Meanwhile, their solid‐state fluorescence can be reversibly switched between crystalline and amorphous structures through alternating grinding and solvent fuming, exhibiting good fatigue resistance. In addition, the molecules also exhibit distinct dual‐mode photochromic behaviors owing to the presence of cyanostilbene moieties: under 420/365 nm light irradiation, the fluorescence of which decreases in solution owing to the photo‐isomerization, while decreases and blue‐shifts in the aggregated state owing to the photodimerization reactions. The reversible, tractable, and high‐contrast mechanochromism and distinct photochromism of the cyanostilbene‐containing molecules endow them with excellent application prospects in the field of rewritable papers and photo‐patterning.