Applications of Organic Electrochemical Transistors in Flexible Bioelectronics

Flexible bioelectronics, offering soft functionalized interfaces to couple biology and electronics, have gained increasing interest due to its great promise in personalized health monitoring, point-of-care diagnosis, and the Internet of Things (IoT). Organic electrochemical transistors (OECTs), capable of mixed ionic-electronic transport, have been widely implemented in flexible bioelectronics due to their flexibility, biocompatibility, high transconductance, low working voltage, design diversity, and facile manufacturing. In this review, we focus on the representative bioelectronic applications of flexible OECTs. We first introduce the device physics of OECTs, with a highlight on their identifying features compared to conventional field-effect transistors. Then, the state-of-the-art channel materials used in OECTs are summarized, with discussions on their figures of merit. Followed by an introduction to the main techniques employed for fabricating flexible OECTs, we examine the up-to-date progress in flexible OECTs for bioelectronic applications, including diverse biosensors, electrophysiological monitoring, and neuromorphic devices. Accompanied by a concise summary, the challenges and opportunities in the commercialization of flexible OECTs are discussed.