High Iontronic Performance in Organic Electrochemical Transistors Enabled by Intramolecular Noncovalent Interactions

Abstract Organic electrochemical transistors (OECTs) show great potential in bioelectronics due to their iontronic coupling, low driving voltages (<1 V), and biocompatibility. Nevertheless, their low iontronic performance, particularly in terms of transconductance ( g m ), limits their ability to acquire high‐precision biosignals. To address this issue, a series of poly(bithiophene)s (opg2T‐O, opg2T‐S, and opg2T‐Se) bearing 4,4′‐position glycol side chains are synthesized. Upon varying furan, thiophene, and selenophene comonomers, the intramolecular noncovalent interactions are systematically tuned. Comprehensive theoretical analyses reveal that opg2T‐Se demonstrates stronger intramolecular Se···O noncovalent interactions than the S···O interactions in opg2T‐S and opg2T‐O, affording a more planar and rigid molecular configuration in opg2T‐Se. Meanwhile, opg2T‐Se exhibits closer π – π stacking and lamellar‐packing and prefers an edge‐on orientation. Consequently, a record‐high geometry‐normalized transconductance ( g m,n ) of 415 S cm −1 , along with remarkable hole mobility ( µ = 2.99 cm 2 V −1 s −1 ) and volumetric capacitance ( C * = 423.3 F cm −3 ) are achieved in opg2T‐Se based OECTs. Importantly, the opg2T‐Se‐based devices exhibits much higher signal fidelity in in‐vitro human electrocardiogram (ECG) than the other two devices. This study highlights the importance of intramolecular noncovalent interaction in the channel layer materials for achieving high‐performance OECTs.