To date, high-performance organic electrochemical transistors (OECTs) are mostly based on polythiophene systems. Donor-acceptor (D-A) conjugated polymers are expected to be promising materials for OECTs owing to their high mobility...

Organic electrochemical transistors (OECTs) have shown great potential in bioelectronics and neuromorphic computing. However, the low performance of n-type OECTs impedes the construction of complementary-type circuits for low-power-consumption logic circuits and high-performance sensing. Compared with their p-type counterparts, the low electron mobility of n-type OECT materials is the primary challenge, leading to low μC* and slow response speed. Nevertheless, no successful method has been reported to address the issue. Here, we find that the charge carrier mobility of n-type OECTs can be significantly enhanced by redistributing the polarons on the polymer backbone. As a result, 1 order of magnitude higher electron mobility is achieved in a new polymer, P­(gPzDPP-CT2), with a simultaneously enhanced μC* value and faster response speed. This work reveals the important role of polaron distribution in enhancing the performance of n-type OECTs.

Porous morphologies have shown great potential in optimizing the capacitance and charge carrier transport for semiconducting polymers in organic electrochemical transistors (OECTs). Nevertheless, it remains arduous and time-consuming to obtain such desired microstructures due to the requirement of rigorous humidity control and templates/additives. Herein, three new glycolated conjugated polymers based on a fused-ring cyclopentadithiophene (CPDT) skeleton are developed, which feature readily obtained large-area porous thin films via spin-casting from binary solvent mixtures under ambient conditions. These polymers afford fascinating capacitances reaching a maximum of 353 F cm −3 , which is the highest value reported to date for p-type OECT materials. The optimal combination of volumetric capacitance and hole mobility in a representative polymer enables the fabrication of OECTs with a high μC* value up to 476 F cm −1 V −1 s −1 and a current retention of 98% upon 600 switching cycles. Moreover, the corresponding flexible OECTs exhibit exceptional mechanical stability at various bending radii down to 5 mm and under repetitive bending cycles. This work provides a simple yet effective binary solvent strategy to fabricate porous conjugated polymers for high-performance OECTs and flexible devices, which will further advance the development of organic mixed ionic−electronic conductors in OECT research fields and beyond.

Organic electrochemical transistors (OECTs) utilize ion flow from the electrolyte to modulate the electrical conductivity of the whole bulk organic semiconductor channel. With the characteristic of mixed ionic-electronic conducting in the entire volume, OECTs exhibit high transconductance and act as good transducers, particularly in bioelectronics. To gain high-performance OECTs, developing novel high-performance polymeric semiconductors is important. In this article, operation principles, performance evaluations, and polymerization methods are first discussed. We then analyze the molecular design strategies for high-performance OECT materials and highlight the characteristics and effects of backbone design and side chain engineering. Finally, we discuss some neglected and unsolved issues and provide an outlook for the OECTs research and development.