Boosting Circularly Polarized Luminescence of Organic Conjugated Systems via Twisted Intramolecular Charge Transfer

Abstract

Realizing a high luminescence dissymmetry factor ( g lum ) 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 g lum values. Interestingly, single-crystalline o -1 exhibited a high-level brightness and a large g lum factor as high as +0.13, whereas single-crystalline o -2 processed a relatively low brightness with a decreased g lum 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.