Regiorandom Polythiophenes for Fully Stretchable Electrochemical Transistors and Logic Circuits

ABSTRACT Regiorandom (RRa) polythiophenes have long been considered unsuitable for highperformance electronics owing to their poor molecular ordering and limited carrier transport. In this study, we demonstrate that RRa polythiophenes, when employed in organic electrochemical transistors (OECTs), exhibit unexpectedly efficient charge transport enabled by volumetric electrochemical doping. Among various alkyl side chains, RRa‐poly(3‐decylthiophene) (P3DT, C10) offers the optimal OECT performance, achieving an on‐state current of ≈160 µA in the saturation regime and an on/off ratio of ≈10 4 , which significantly surpasses the typical performance of disordered polymers. Remarkably, RRa‐P3DT maintains electrical characteristics under large strains of up to 200%, owing to its irregular structure. Fully stretchable OECTs were fabricated by integrating RRa‐P3DT with a single‐walled carbon nanotube (SWCNT) gate electrode and an ionogel electrolyte, retaining stable switching characteristics under 100% strain and occupying the upper‐right corner of the on/off ratio–stretchability plot, thereby outperforming most reported intrinsically stretchable OECTs. Moreover, the successful demonstration of stretchable logic gates including inverters, NAND, and NOR highlights the untapped potential of amorphous polymer semiconductors for stretchable electronics.