A conjugated polymer pn junction.

Dopant counterion diffusion has made the conjugated polymer pn homojunction a challenging target for decades. We report the electrochemical fabrication of a polyacetylene pn homojunction based on internally compensated forms where the dopant counterions are covalently bound to the polymer backbone. After drying under vacuum, the pn junction exhibits diode behavior with the ratio of the forward to reverse current at 2 V being 7. Despite such modest diode behavior, the fabricated pn junction is significant because it demonstrates the utility of internal compensation in the fabrication of metastable interfaces between dissimilarly doped conjugated polymers.