Stimuli-responsive solid-state emission from o-carborane–tetraphenylethene dyads induced by twisted intramolecular charge transfer in the crystalline state was demonstrated.

Realizing a high luminescence dissymmetry factor (glum) is a paramount yet challenging issue in the research field of circularly polarized luminescence (CPL). Here, we reported a novel set of organic conjugated systems with twisted intramolecular charge transfer (TICT) characteristics based on conjugated o-carborane-binaphthyl dyads composing of binaphthyl units as chiral electron donors and o-carborane units as achiral electron acceptors, demonstrating intense CPL with large glum values. Interestingly, single-crystalline o-1 exhibited a high-level brightness and a large glum factor as high as +0.13, whereas single-crystalline o-2 processed a relatively low brightness with a decreased glum value to -0.04. The significant diversity of CPL-active properties was triggered by the selective introduction of o-carborane units onto the binaphthyl units. Benefiting from the large magnetic dipole transition moments in TICT states, the CPL activity of TICT o-carborane-based materials exhibited amplified circular polarization. This study provides an efficient molecular engineering strategy for the rational design and development of highly efficient CPL-active materials.

Stimuli-responsive circularly polarized luminescence (CPL) was successfully achieved through fine-tuning the conformation of a perylenyl dyad by using external stimuli. Monomer CPL was clearly detected from an inherent achiral monochromophore system in a simple perylene-carbazole dyad, and concentration-dependent CPL was observed from 'good solvent', giving an excimer-like CPL emission with a peak maximum at 643 nm. Moreover, the CPL bands depended on the aggregated state, which was identical to the emission changes in the THF-HO system. It is noteworthy that the perylene-carbazole dyad emitted efficient CPL in thin films even without annealing processes. The specific perylenyl-carbazole structure plays a crucial role in CPL in response to the external environment. This novel molecular design strategy opens up a new perspective for the future development of smart CPL-active organic dyads.

Circularly polarized luminescence from a boron ketoiminate-based π-conjugated polymer was successfully realized at the unimolecular level via conformational locks that blocked the intramolecular rotations.