Simulating Current Transients in Polymers from First-principles

Abstract

Recently, we have developed a first-principles based multi-scale modeling approach for computing the carrier mobilities in polymeric dielectric. In this work, time-of-flight transient current waveforms are simulated without adopting empirical or phenomenological models. Our calculations demonstrate that dispersive charge transport takes place in thin polyethylene films, and in line with experimental findings, the simulated current waveforms exhibit a peak, plateau, and a long tail. Dispersive transient currents in insulating polymers are often interpreted in terms of semi-phenomenological Scher-Montroll theory, owing to the somewhat satisfactory fitting to the experimental data. We show that even though the underlying assumption in the model is not fulfilled, the simulated current waveforms “happen to” obey the universality predicted by the Scher-Montroll theory as observed in experiments. Since, current waveforms have more information than the carrier mobilities, we believe that our computational approach will provide a more detailed understanding and insights on the carrier transfer properties in amorphous insulating polymers.