Dielectric switching studies of polyvinylidene fluoride thin films with dominant planar ferroelectric domain configuration for flexible electronic devices

Abstract

Electrical switching characteristics of the polymer chains of polyvinylidene fluoride (PVDF) thin films with dominant planar domain configuration were investigated in this work. PVDF a semi-crystalline piezoelectric polymer is known to undergo structural transformation when subjected to electric field. In this study, the I-V characteristics of PVDF was analyzed by varying the delay time from 0.1 to 0.001 seconds in order to understand the response of switching behavior; a promising attribute that governs the operational speed of the device. A hysteretic behavior in the I-V characteristics was observed at different drive voltages. The ferroelectric polarization domains responds at different voltages and give rise to polarization switching currents. In addition to this, at relatively larger voltages (> 10 V) the amorphous intermediate regions of PVDF is expected to undergo an amorphous to crystalline transformation. Hence, the switching characteristics of the ferroelectric domains in the form of switching currents and the dipolar re-orientation arising due to the amorphous to crystalline transformation by rotation of polymer chains are captured at different voltages. Furthermore, a longer delay time (0.1 seconds) is employed to capture the current arising from a reversible amorphous to crystalline transformation. The dielectric relaxation time for the rotation of polymer chains in PVDF was inferred from independent studies and observed to be between 100 to 500 μS. © 1994-2012 IEEE.