Facilely Accessible Porous Conjugated Polymers toward High-Performance and Flexible Organic Electrochemical Transistors

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.