Ferroelectricity in a hydrogen-bonded alternating donor-acceptor supramolecular copolymer.

This communication reports synergistic H-bonding and charge-transfer (CT) interaction-promoted alternating supramolecular copolymerization of amide-functionalized pyrene (Py) and naphthalene-diimide (NDI) building blocks and the emergence of ferroelectricity with saturation polarization ∼3.2 μC cm, Curie temperature ∼304 K, and coercive field ∼8.5 kV cm at 100 Hz. The Py or NDI molecules on their own do not exhibit any ferroelectric hysteresis, indicating an essential role of both CT-interaction and H-bonding in ferroelectricity. Computational studies provide insight into the origin of the polarization and the importance of the NDI/Py ratio. This study, showing room temperature ferroelectricity in purely organic systems, is of high relevance for flexible electronics and sensors. It opens up new opportunities for soft FE-materials with ample scope for further structural optimization.