Non-classical control of solid-state aggregation-induced enhanced circularly polarized luminescence in chiral perylene diimides

Organic fluorescent molecules are gaining importance because of their potential applications in many devices. Optically active N,N′-bis((1R)-1-naphthylethyl)perylene-3,4,9,10-tetracarboxylic diimide [(R,R)-1-BNP] and N,N′-bis((1R)-2-naphthylethyl)perylene-3,4,9,10-tetracarboxylic diimide [(R,R)-2-BNP] and their antipode, [(S,S)-1-BNP and (S,S)-2-BNP], emit aggregation-induced enhanced (AIEnh) circularly polarized luminescence (CPL) on both a solid organic polymer film (poly(methyl methacrylate)) and solid inorganic KBr pellet. An opposite chirality is essential for generating CPL of inverted sign. However, a pair of enantiomeric organic molecules may not always be easy to prepare. Interestingly, the chiral perylene fluorophores synthesized in this study can emit both positive and negative AIEnh-CPL in the solid state, depending on their position on the naphthylene groups. In addition, no CPL was observed in these compounds from their dilute solutions.