Helically-Locked π-Conjugated Oligomers and Polymers with Tunable Twist

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The performance of organic electronic materials is strongly dependent on their conformation. Twisting these materials out of planarity induces chirality and thus results in new electronic, magnetic, and optical properties with increasing numbers of applications as non-liner optical devices, spin filters, and magneto-optical devices. However, the effect of twisting is poorly understood, as it is difficult to isolate from other factors. Moreover, twisting often comes at the expense of π-conjugation, resulting in inferior device performance. Using a novel approach, I propose to address this challenge by introducing a new family of helically-locked organic electronic materials, oligomers and polymers, in which the twist of the π-conjugated backbone can be finely tuned. This will allow us to monitor and understand the effects of twisting on the electronic, optical, and magnetic properties of organic electronic materials. Unlike most chiral conjugated materials, the proposed approach allows the formation of polymers with a tunable twist, helical backbone chirality and strong π-conjugation, a combination often difficult to obtain. Following our preliminary findings, which successfully demonstrated the helical locking of small acene units to a specific twist angle, my team will focus on five ambitious projects: 1) Synthesis of extendable twistacene units. 2) Synthesis of helically-chiral oligomers polymers with tuneable twist. 3) Study of the effect of twisting on the charge and energy transfer processes. 4) Synthesis of open shell twisted acenes. 5) Understanding the effect of twisting on the magneto-optical properties and chiral-induced spin selectivity. The successful introduction of the abovementioned twisted backbones will allow us to understand the influence of molecular structure on fundamental properties of organic electronic materials, and the acquired knowledge will lead to design new materials for efficient optoelectronic, magneto-optic and spintronic devices.