Dielectric properties of regioregular poly(3-alkylthiophene) films

The a.c. behaviour of structures of Aluminium-regioregular poly(3-octylthiophene)-indium-tin oxide is analyzed as a function of the frequency of a small a.c. voltage and a d.c. bias voltage. Strong frequency dispersion of capacitance is observed and is mainly attributed to a combination of deep traps in the bulk of the polymer and to the presence of an interfacial layer at the metal/polymer interface. An equivalent circuit is proposed.