Organic Mixed Ionic Electronic Conductor Nanochannels for Vertical Electrochemical and Ionic Transistors

Thin films of organic mixed ionic electronic conductors (OMIECs) constitute the functional layer in organic electrochemical transistors (OECTs), organic bioelectronic transducers and other ionic-electronic devices. The thin-film configuration constrains devices to be fabricated on impermeable substrates in the form of 2D microstructures with lateral electrodes to drive an electronic current through the thin film. In order to alleviate such constraints, novel OMIEC deposition methods are needed that produce alternatives to thin-film devices and that are compatible with permeable substrates and electronic transport in the vertical direction. Here OMIECs filled nanoporous membranes are introduced as functional layer in devices with mixed ionic electronic transport. Electropolymerization of ethylenedioxythiophene (EDOT) monomers is used to fabricate OMIEC filled nanochannels. Electronic and ionic transport through such nanochannels are investigated and modulation of electronic as well as ionic carrier density by action of a third gate electrode is demonstrated. The novel OMIEC nanochannels enable the fabrication of vertical OECTs with high transconductance and organic ionic transistors using only additive fabrication methods. A method is developed to electropolymerize PEDOT based organic mixed ionic electronic conductors into the nanochannels of tracketched membranes. Gated electronic and ionic transport through the membranes is investigated. The results demonstrate that the method gives access to high transconductance vertical OECTs fabricated without photolithography and to novel ionic transistors. image