Confinement of PEDOT:PSS in Covalent Organic Frameworks for Stable Organic Electrochemical Transistors

Organic electrochemical transistors (OECTs) are attractive for wearable bioelectronics and smart textiles owing to their mixed ionic-electronic conduction and biocompatibility. The function of these transistors relies on a channel made of a 1D conducting polymer, which is essential for converting ionic signals into amplified electronic outputs. However, classical 1D polymer channels such as PEDOT:PSS suffer from severe swelling and instability in aqueous environments, limiting device reliability. Here, we introduce a framework-confinement strategy that inserts PEDOT:PSS into the nanopores of β-ketoenamine covalent organic frameworks (COFs) functionalized with carboxyl or sulfonic groups. Strong hydrogen-bonding interactions effectively suppress polymer swelling, thereby enhancing long-term operational stability. The composite COF/PEDOT:PSS fibers, produced via scalable wet-spinning, exhibit remarkable mechanical robustness with a tensile strength of 464.7 MPa. As OECT channel materials, the fibers retain over 90% of their initial performance after 1000 s of cycling, demonstrating exceptional durability. This work offers a promising route to overcome the problem of structural failure of 1D conductive polymers in aqueous media, paving the way for high-performance and durable bioelectronic textiles.