Evaluation of ferroelectric profile of poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-TrFE)) thin films by positive-up–negative-down and fatigue measurement

Abstract

Organic polymers are of interest due to their numerous promising potential applications in the area of energy harvesting and sensing. In this context, piezoelectric and ferroelectric polymers are subject to intense research; however, it is challenging to understand polarization switching in such systems. The focus of the present study is to thoroughly evaluate the finer details of polarization reversal in poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-TrFE)) thin films. The intrinsic features arising from the true values of (switching) polarization and extrinsic features associated with the presence of non-switching contributions, i.e. leakage current and linear dielectric component, have been investigated using the positive-up–negative-down technique. These contributions are quantified and discussed. Furthermore, fatigue endurance has been examined by repeated switching cycles. Increase in polarization increases is associated with the improved crystallinity and enhancement of the β-phase. However, a higher degree of crystallinity, for extended numbers of repeated cycles of the bipolar electric field, resulted in degradation of the (switching) polarization. Fatigue significantly affects the leakage and ferroelectric components while the paraelectric contribution remains almost constant. The underlying mechanism of such trends are discussed in terms of hysteresis losses. © 2023 Society of Industrial Chemistry.