A Semiconducting Conjugated Radical Polymer: Ambipolar Redox Activity and Faraday Effect

Investigations of magnetism in electronically coupled polyradicals have largely focused on applications in photonic and magnetic devices, wherein radical polymers were found to possess molecularly tunable and cooperative magnetic properties. Radical polymers with nonconjugated insulating backbones have been intensively investigated previously; however the integration of radical species into conducting polymer backbones is at an early stage. We report herein 1,3-bisdiphenylene-2-phenylallyl (BDPA)-based conjugated radical polymers that display ambipolar redox activities and conductivities. Moreover, these radical polymers were demonstrated to be promising magneto-optic (MO) materials with Faraday rotations wherein the sign is modulated by the radical character and display absolute Verdet constants up to (2.80 ± 0.84) × 104 deg T–1 m–1 at 532 nm. These values rival the performance of the present-day commercial inorganic MO materials (e.g., terbium gallium garnet, V = −1.0 × 104 deg T–1 m–1 at 532 nm). The structure property studies detailed herein reveal the promise of multifunctional conjugated radical polymers as responsive MO materials