Energy storage behaviors in ferroelectric capacitors fabricated with sub-50\u2009nm poly(vinylidene fluoride) Langmuir–Blodgett nanofilms

Abstract

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\u2009MV/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\u2009nm thicknesses. The ferroelectric hysteresis loops were measured using a Sawyer–Tower circuit in different electric fields. An energy density of 6.0\u2009J/cm3 at 500\u2009MV/m was demonstrated for the 12-nm-thick PVDF LB nanofilm device.Polar polymers with permanent dipoles such as poly(vinylidene fluoride) (PVDF) are suitable for use as high-energy storage density dielectrics because of their high permittivity. This study investigated the ferroelectricity and energy storage behaviors of PVDF Langmuir–Blodgett (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.