Faradaic effects in all-organic transistors

Electrochemical (Faradaic) effects play an important role in the unusual field-effect phenomenon observed in an all-organic transistor-type device that use films of doped electronic polymers, such as polyaniline (emeraldine-HCl) and poly-3,4-ethylenedioxythiophene polystyrene sulfonate, as the channel and gate. Small leakage currents through the dielectric are sufficient to affect reversible redox reactions in the polymer film in the active region of the device, i.e., where the channel and gate regions overlap. In the case of polyaniline, these redox reactions are accompanied by color changes corresponding to the different oxidation states of polyaniline that can be visually observed and also spectroscopically monitored.