Photo-induced morphology transition of a multifunctional photochromic bisthienylethene molecule with switchable aggregation-induced emission

A novel multifunctional molecule BTE-CNPH was designed and synthesized by connecting 2-(3′,5′-bis(trifluoromethyl)-biphenyl-4-yl)-2-cyanovinyl group to both side of the bisthienylethene (BTE), which exhibited excellent aggregation-induced emission (AIE) and bistable photochromism. High-contrast (>60) reversible fluorescence switching was achieved in the 1D nanowires, solid of BTE-CNPH and also in a polymethyl methacrylate (PMMA) film loaded with 1% BTE-CNPH under the alternative irradiation by 365 nm and visible light. Interestingly, the nanowire-like assembly morphology of BTE-CNPH in aqueous tetrahydrofuran (THF) solution of specific concentration was observed to translate into amorphous pieces gradually upon prolonged irradiation by the 365 nm, accompanying with photo-tunable AIE emission.