Energy storage behaviors in ferroelectric capacitors fabricated with sub-50 nm poly(vinylidene fluoride) Langmuir–Blodgett nanofilms

High-energy storage in polymer dielectrics is limited by two decisive factors: low-electric breakdown strength and high hysteresis under high fields. Poly(vinylidene fluoride) (PVDF), as a well-known ferroelectric polymer having a high-breakdown strength (700 MV/m) and a high dielectric constant, is suitable for use as a dielectric capacitor film, but ferroelectric hysteresis from the crystalline phase has prevented its practical application. In our previous study, the ferroelectric switching of crystalline PVDF is suppressed effectively in PVDF-based Langmuir–Blodgett (LB) nanofilms because of its large interfacial effect, even in an extremely high electric field. This study investigated the ferroelectricity and energy storage behaviors of PVDF LB nanofilms at sub-50 nm thicknesses. The ferroelectric hysteresis loops were measured using a Sawyer–Tower circuit in different electric fields. An energy density of 6.0 J/cm³ at 500 MV/m was demonstrated for the 12-nm-thick PVDF LB nanofilm device.