A Material-Agnostic Self-Assembly Strategy for Uniform Patterning of Conjugated Polymers Unveils the True Role of Porosity in Organic Electrochemical Transistors

Organic electrochemical transistors (OECTs) achieve high transconductance at low operating voltages upon ionic doping, making them promising candidates for advanced bioelectronics. While introducing porosity in OECT channels has been proposed as a strategy to enhance ion accessibility, its universal effectiveness and underlying mechanisms remain unclear without reliable strategy for well-defined pore formation and concurrent changes in polymer chemistry. Here, we report a generalizable patterning strategy for regular porous yet chemically-intact conjugated polymer channels by using hexagonally self-assembled colloidal templates. By systematic investigation on conjugated polymers with diverse backbone ordering and side-chain polarity, we identify that porous structure does not always enhance device performance and instead identify composition-dependent regimes in which porosity is beneficial. Moreover, we elucidate key factors governing transconductance enhancement, including charge carrier mobility, volumetric capacitance, and effective doped volume. This study establishes generalized microstructural design rules for optimizing OECT performance and provides a valuable platform for engineering high-performance devices.