Enhanced piezoelectricity and pyroelectricity in poly(vinylidene fluoride-co-tetrafluoroethylene) via hot pressing

Ferroelectric polymers have been intensively explored for flexible and wearable applications. Most studies concentrate on poly(vinylidene fluoride) and its copolymer poly(vinylidene fluoride-co-trifluoroethylene), and little attention has been given to poly(vinylidene fluoride-co-tetrafluoroethylene) owing to its weak piezoelectricity and pyroelectricity despite its dramatically lower cost. Here, it is reported that both piezoelectricity and pyroelectricity are markedly enhanced in poly(vinylidene fluoride-co-tetrafluoroethylene) via a hot-pressing technique. The long-range ferroelectric phase with improved crystallinity is stabilized via hot pressing, leading to an enhanced piezoelectric coefficient d33 of −42.2 pC N−1 and a pyroelectric coefficient of 83.8 μC m−2 K−1, outperforming the benchmarks poly(vinylidene fluoride) and poly(vinylidene fluoride-co-trifluoroethylene) 80/20 mol. % while preserving a high Curie temperature of more than 160 °C. Moreover, this strategy yields outstanding piezoelectric and pyroelectric figures of merit. These findings pave the way toward the scalable fabrication of high-performance ferroelectric polymers for piezoelectric and pyroelectric applications.