Carbon-based Microfabricated Organic Electrochemical Transistors Enabled by Printing and Laser Ablation

TL;DR

This paper introduces a rapid, eco-friendly method for fabricating high-resolution, biodegradable organic electrochemical transistors using printing and laser ablation, eliminating the need for cleanroom processes.

Contribution

It presents a novel additive-subtractive microfabrication strategy for metal-free, flexible OECTs with micrometer resolution and versatile architectures, using biodegradable materials and room-temperature processing.

Findings

Achieved micrometer-scale patterning with laser ablation down to 1 um.

Demonstrated fabrication of various OECT architectures including inverters.

Provided a low-energy, environmentally friendly disposal route for devices.

Abstract

Organic electrochemical transistors (OECTs) are key bioelectronic devices, with applications in neuromorphics, sensing, and flexible electronics. However, their microfabrication typically relies on precious metal contacts manufactured via cleanroom processes. Here, we present a high-throughput additive-subtractive microfabrication strategy for metal-free, flexible OECTs using biodegradable materials and room-temperature processing. Additive manufacturing of large features is achieved via extrusion printing of a water-dispersed graphene ink to fabricate electrode contacts, and spin-coating of a cellulose acetate ink to form both the substrate and encapsulation layer. Combined with femtosecond laser ablation, this approach enables micrometer-resolution patterning of free-standing OECTs with channel openings down to 1 um and sheet resistance below 10 Ohm/sq. By tuning laser parameters, we demonstrate both selective and simultaneous ablation strategies, enabling the fabrication horizontal, vertical, and planar-gated OECTs, as well as complementary NOT gate inverters. Thermal degradation studies in air show that over 80% of the device mass decomposes below 360 deg C, providing a low-energy route for device disposal and addressing the environmental impact of electronic waste. This approach offers a cleanroom-free and lithography-free pathway toward the rapid prototyping of high-resolution, sustainable organic electronics, combining material circularity, process simplicity, and architectural versatility for next-generation bioelectronic applications.