Electrical characterization of diodes based on regioregular poly(3-hexylthiophene)

Conjugated polymer films were sandwiched between thin aluminium and gold electrodes in orderto determine current-voltagecharacteristics of the three-layer device. Poly (3-hexylthiophene) fractions different in their degrees of polymerization were used as the representatives of conjugated systems with different chain lengths. The analysis of the data showed that morphology of the polymer film and length of the chain influence the operation voltage of the device. Moreover, due to the position of the Fermi levels of the electrodes and HOMO (LUMO) levels, the device works in single-carrier current regime and space-charge limitation of current is present.