Stimuli-responsive chiral aggregation-induced emission luminogens and their circularly polarized luminescence

Abstract

Circularly polarized luminescence (CPL) has attracted considerable attention in diverse systems and has rapidly developed into an emerging research field, in which stimuli-responsive CPL-active materials are expected to be useful in various fields. Herein, a series of chiral emitters combining the commercially available BINOL moiety and emitting cyanostilbene (CS) units featuring aggregation-induced emission (AIE) properties were feasibly prepared. All these chiral AIEgens displayed internal charge transfer under a low water content and AIE process after the formation of nano-aggregates with high emission efficiency. The light-pumped cis–trans isomerization of the CS moiety and donor–π–acceptor structure with strong electron-withdrawing benzothiazole groups endowed these chiral luminogens with adaptive luminescence to light irradiation and medium polarity. In addition, all these chiral AIEgens displayed weak CPL signals as nano-aggregates and in a polymer film, whereas an amplified and inverted CPL signal with a g_lum of ±0.3 was recorded in commercially available nematic liquid crystals (LCs). Moreover, light irradiation and medium polarity could be leveraged to modulate the CPL intensity, emission colour and sign of these chiral AIEgens in LCs and polymer matrixes.