Interaction of interfacial charge and ferroelectric polarization in a pentacene/poly(vinylidene fluoride-trifluoroethylene) double-layer device

A two-step polarization reversal process was identified in the pentacene/poly(vinylidene fluoride-trifluoroethylene) double-layer device. Displacement current measurement showed that three peaks generated non-symmetrically in the current-voltage characteristics. Accordingly, optical electric-field induced second-harmonic generation measurement displayed two hysteresis loops. A proposed model based on a two-step polarization reversal mechanism accounted for these results, and suggested that interaction of interfacial charge and ferroelectric polarization governed the mechanism. The proposed model is useful to explain the reduced remanent polarization in ferroelectric field-effect transistors, and will be helpful for developing organic devices with a ferroelectric layer.