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.