Sample length independent conduction current in polyethylene oxide

摘要

The transient current density through ion conducting polyethylene oxide samples of different lengths is measured after application of voltage steps with different amplitudes. In the experiments, it is found that at a given voltage step the long-term current density is independent of the sample length. Qualitatively, the same behavior is attained from computer simulations using a three-dimensional hopping model which takes into account internal ionic charge movements and extrinsic electronic charge injection from the electrodes. It turns out that the width of a depletion zone of mobile ions at the electrode, which only depends on the applied voltage, is responsible for the independence of the current from the sample length.