Implanted polymer junctions from highly compacted polypyrrole films

Electrochemical techniques allow the control of the morphology of conducting polymers. After synthesis, polypyrrole films grafted on aluminium electrodes can be electrochemically reduced at very low cathodic potentials, obtaining bulk conductivities of 10−6 S cm−1, stable for months. This high stability is attained by means of the closure of the polymeric entanglement during the cathodic treatment, which hinders oxygen diffusion through the polymer, avoiding self-doping processes. After implantation of alkali ions, polypyrrole-based p—n junctions, stable for several months, are obtained.