Frequency Selectivity in Pulse Responses of a Pt/Poly(3-hexylthiophene-2,5-diyl)/Polyethylene Oxide + Li+/Pt Hetero- junction

The direct current characteristics were not symmetric in the sweeping range of ±2 V.Negative differential resistance appeared in the input range of 0 to 2 V because of de-doping (or reduction) in the side with the semiconductor layer. The device responded stably to a train of pulses with a fixed frequency.

The inverse current after a pulse was related to the back-migrated ions. Importantly, the weight calculated based on the inverse current strength, was depressed during low-frequency stimulations but was potentiated during high-frequency stimulations when pulses were positive. Therefore, frequency selectivity was first observed in a semiconducting polymer/electrolyte hetero junction.