Interface Engineering in Organic Electrochemical Transistors toward Multifunctional Bioelectronics

Abstract

Bioelectronics bridges electronic systems and living organisms by enabling bidirectional transduction between ionic/biochemical signals and electronic outputs. Among emerging platforms, organic electrochemical transistors (OECTs) have become particularly promising for biointerfaces due to their electrolyte-driven volumetric doping mechanism, high transconductance, low operating voltage, and intrinsic compatibility with soft, aqueous biological environments. Based on conjugated polymers with tunable physicochemical properties and solution processability, OECTs support scalable, flexible, and multifunctional bioelectronic systems for sensing, neural interfacing, and adaptive electronics. Critically, the performance, stability, and multifunctionality of OECTs are governed by interfacial phenomena, including electrolyte/channel, channel/electrode, and device/tissue interactions. Surface engineering plays a central role in regulating ion transport, charge injection, capacitance, and biocompatibility, while enabling intelligent and responsive functionalities. This review highlights recent advances in surface-engineered OECTs, summarizes key strategies for multifunctional integration, and discusses current challenges and future directions toward next-generation bioelectronic devices.