Fully 3D-Printed Organic Electrochemical Transistors

TL;DR

This paper introduces a fully 3D-printed organic electrochemical transistor platform using novel printable inks, enabling flexible, scalable, and stable devices suitable for biosensing and neuromorphic applications.

Contribution

It presents the first fully 3D-printed OECTs with compatible inks and substrate, advancing additive manufacturing in organic electronics.

Findings

Operates in depletion mode with high stability

Detects dopamine down to 6 μM without metal gate

Demonstrates long-term synaptic response (~1 hour)

Abstract

Organic electrochemical transistors (OECTs) are currently being investigated for various applications, ranging from sensors to logics and neuromorphic hardware. The fabrication process must be compatible with flexible and scalable digital techniques to address this wide spectrum of applications. Here, we report a direct-write additive process to fabricate fully 3D printed OECTs. We developed 3D printable conducting, semiconducting, insulating, and electrolyte inks to achieve this. The 3D-printed OECTs, operating in the depletion mode, can be fabricated on thin and flexible substrates, yielding high mechanical and environmental stability. We also developed a 3D printable nanocellulose formulation for the OECT substrate, demonstrating one of the first examples of fully 3D printed electronic devices. Good dopamine biosensing capabilities (limit of detection down to 6 uM without metal gate electrodes) and long-term (~1 hour) synapses response underscore that the present OECT manufacturing strategy is suitable for diverse applications requiring rapid design change and digitally enabled direct-write techniques.