Conduction behavior of doped polyaniline films at high current density regime

The conduction behavior at high current density at room temperature and above of polyaniline (PANI) films doped with HCl and camphor sulfonic acid (HCSA), respectively, is reported. It is found that the current density deviates strongly from the linear relation with the electric field in high current density region, and a saturation of the current density is observed. The maximum current density J_m seems to be proportional to the conductivity of the sample and hence, for PANI doped with HCl, J_m is about 200 A/cm^2, whereas for HCSA doped samples, J_m can reach more than 1,200 A/cm². The saturation of current density is interpreted as being caused by space charge accumulation at the insulating barrier regions and a dedoping effect in the conduction domains due to the detraping of the ions under high fields. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 2845–2850, 1999