Aggregation-morphology-induced amplification and inversion of CPL in N-chiral substituted indolocarbazole derivatives.

Circularly polarized luminescence (CPL) materials hold broad application prospects in chiral optoelectronic devices and other fields, and the precise regulation of aggregation morphologies to achieve CPL signal amplification and inversion is a research priority in this field. In this study, two chiral alkyl chain-modified indolo[3,2-b]carbazole derivatives, ICZ-2S/R and 2HICZ-2S/R, were designed and synthesized. Their self-assembly behaviors were regulated via antisolvent-induced and interfacial assembly strategies, yielding aggregates with distinct micro-morphologies in the solution aggregate state and spin-coated film state. The derivatives exhibited only weak CPL signals in the solution aggregate state, while significant CPL signal amplification and sign inversion were realized in the spin-coated film state, with the CPL intensity of ICZ-2Rfilm being nearly 6 times higher than that in the solution state. Combined analyses of ICZ-2S single crystal revealed that the crystal-like long-range ordered mesoscopic helical packing driven by edge-to-face C-H···π interactions in the film is the core mechanism for its excellent chiroptical performance. This work provides an efficient morphology regulation strategy for modulating the CPL properties of chiral N-containing polycyclic π-conjugated molecules, and also offers important references for the design and development of high-performance tunable CPL materials.