Strain‐Enhanced Ultrastretchable Semiconducting Polymer Fibers for Organic Electrochemical Transistors

ABSTRACT Wearable electronics and soft bioelectronics require stretchable devices with steady performance under deformation. However, the balance between electrical performance and stretchability remains a critical obstacle, and most approaches sacrifice charge transport mobility to achieve stretchability. Herein, we present a material design concept that utilizes a wet‐spinning strategy to fabricate highly stretchable semiconducting polymer fibers, enabling high‐performance organic electrochemical transistors (OECTs) with stable or even enhanced charge transport mobility under large strains. The polymer chains are ordered within the fibers under the shear effects of the spinning fluid and can reorient during stretching to dissipate strain energy, further forming a more compact and ordered molecular arrangement. As a result, the fabricated semiconductor fiber can be stretched to over 250% strain and exhibit an ultrahigh normalized transconductance of 276.4 S cm −1 , far exceeding thin‐film polymer semiconductors. More importantly, the fiber OECTs possess unique strain‐enhanced electrical performance, with substantially improved charge carrier mobility after strain‐induced ordered arrangement of molecular chains. The skin‐like fully stretchable OECTs have been successfully applied for recording electrocardiogram signals. This work provides more possibilities for the further development of stretchable semiconducting polymer materials with high electrical performance.