Ion Modulated Ambipolar Electrical Conduction in Thin Film Transistors Based on Amorphous Conjugated Polymers

Organic ambipolar semiconductors, which have the ability to efficiently transport both holes and electrons, are of great interest for many useful optoelectronic devices, such as light emitting diodes, photovoltaic cells, and thin film transistors (TFTs). To date, very few organic ambipolar transistor materials have been reported. Here we report that through gate modulated electrochemical doping, ambipolar operation can be realized in air with solution processable conjugated polymers. Unlike other typical organic TFTs, which rely on high crystallinity for better charge transport, the new electrochemically doped transistors operate under a different mechanism and showed very high current output even with completely amorphous polymers. This new operation mechanism may lead to the discovery of a broader range of organic semiconductors and novel devices.