π‐Conjugated Polymers for High‐Performance Organic Electrochemical Transistors: Molecular Design Strategies, Applications and Perspectives

The last decade has witnessed significant progress in organic electrochemical transistors (OECTs) due to their enormous potential applications in various bioelectronic devices, such as artificial synapses, biological interfaces, and biosensors. The remarkable advance in this field is highly powered by the development of novel organic mixed ionic/electronic conductors (OMIECs). π-Conjugated polymers (CPs), which are widely used in various optoelectronics, are emerging as key channel materials for OECTs. In this review, after briefly introducing OECT, we then mainly focus on the latest progress in CPs for high-performance OECTs. The correlations of their structure, basic physicochemical properties, and device performance are elucidated by evaluating their electronic characters, optoelectronic properties, and OECT performance. Then, the applications of CP-based OECTs are briefly presented. Finally, we discuss several remaining issues or challenges in this field and give our insights into advancing CPs for enhanced OECT performance.