Efficient Integration of High-transconductance Organic Electrochemical Electronics on Printed Circuit Boards for Sensing Applications

Organic electrochemical transistors (OECTs) are promising platforms for sensing applications due to their high transconductance and low-voltage operation. However, conventional fabrication approaches relying on cleanroom-based microfabrication and costly substrates such as silicon or indium tin oxide glass restrict scalability and practical adoption. This work introduces a cost-effective and scalable fabrication for OECTs by using printed circuit boards (PCBs) as substrates, each costing less than $0.50. Oxygen plasma treatment was employed to transform the surfaces of PCBs from hydrophobic to hydrophilic, thereby enabling the uniform deposition of poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) films. Cross-linking with 3-glycidyloxypropyltrimethoxysilane improved film stability without significantly compromising conductivity, ensuring film robustness over time. Interdigitated contact designs were employed to enhance device performance, yielding transconductance up to 20 mS, ON/OFF ratios of ∼103, and stable operation at gate voltages as low as 0.1 V. The devices retained 86% of the drain current after 1000 switching cycles, demonstrating durability. Finally, the integration of a floating-gate two-chamber system enabled sensitive detection of ferrocyanide ions in water, demonstrating practical utility for environmental monitoring with a maximum sensitivity of 1.096 ± 0.081 mA dec–1. This study establishes a cost-effective, scalable route for high-performance OECTs on PCB substrates, expanding their accessibility for real-world sensing applications.