Porous Semiconducting Polymers Enable High‐Performance Electrochemical Transistors

Abstract Organic polymer electrochemical transistors (OECTs) are of great interest for flexible electronics and bioelectronics applications owing to their high transconductance and low operating voltage. However, efficient OECT operation must delicately balance the seemingly incompatible materials optimizations of redox chemistry, active layer electronic transport, and ion penetration/transport. The latter characteristics are particularly challenging since most high‐mobility semiconducting polymers are hydrophobic, which hinders efficient ion penetration, hence limiting OECT performance. Here, the properties and OECT response of a series of dense and porous semiconducting polymer films are compared, the latter fabricated via a facile breath figure approach. This methodology enables fast ion doping, high transconductance (up to 364 S cm −1 ), and a low subthreshold swing for the hydrophobic polymers DPPDTT and P3HT, rivalling or exceeding the metrics of the relatively hydrophilic polymer, Pg2T‐T. Furthermore, the porous morphology also enhances the transconductance of hydrophilic polymers, offering a general strategy for fabricating high‐performance electrochemical transistors.