Molecular rotation and large polarization in charge-transfer ferroelectric cocrystals.

Organic ferroelectrics offer solution processability, mechanical flexibility and promising applications in sensing, energy storage and actuation. However, their polarization and Curie temperatures are typically lower than those of inorganic ferroelectrics because weak intermolecular interactions hinder efficient dipole alignment. The development of organic materials that integrate dipole units, long-range dipole ordering and switchable polarization may enable the design of high-performance organic ferroelectrics. Here we report a donor-acceptor cocrystal in which V-shaped donor molecules pack into a gear-like arrangement, enabled by supramolecular interactions. Within this binary confined lattice, a cooperative in-plane rotation of 42° by the donor molecules-triggered by an external electric field-enables reversible polarization switching. This rotational mechanism yields a remanent polarization of 58 μC cm-2, stable ferroelectricity up to 479 K and a low coercive field of 0.022 MV m-1, exhibiting superior performance compared with previously reported organic ferroelectrics. These findings provide a pathway towards the design of high-performance organic ferroelectrics.