Fully Printed Organic Electrochemical Transistors With Low‐Resistance Electrodes on Planarized 3D‐Printed Substrates

ABSTRACT This work presents a novel methodology for fabricating organic electrochemical transistors (OECTs) integrated with planarized 3D‐printed substrates, offering a scalable approach to integrate functional electronics into 3D‐printed systems. By combining fused deposition modeling (FDM) with in situ surface ironing, dispense printing for low‐resistance silver electrodes, and inkjet printing for high‐quality poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) channels, we achieve high‐performance transistors with an average transconductance (g m ) of 78.2 mS, one of the highest values reported in the literature. OECTs integrated with planarized 3D printed substrates are compared to devices fabricated on glass substrates and achieved comparable performance. The thick, low‐resistance electrodes produced via dispense printing are critical for this performance, demonstrating the technique's suitability for OECT manufacturing. This study establishes a process for integrating OECTs with 3D‐printed structures, paving the way for customizable, application‐specific electronic devices. By addressing key challenges in material compatibility and integrated fabrication, this work contributes to advancing the fields of bioelectronics, wearables, and additive manufacturing.