Universal material basis for biocompatible printed electrolytes in Organic Electrochemical Transistors

TL;DR

This paper introduces a biocompatible, UV-curable electrolyte for organic electrochemical transistors that enables flexible, printed, and long-lasting bio-compatible electronic devices.

Contribution

It develops a novel biocompatible electrolyte material compatible with inkjet and screen printing, including UV-curable properties for solid-state transition and enhanced device longevity.

Findings

Extended device operation in ambient air for over 30 days

Successful fabrication of a fully screen-printed transistor on a leaf substrate

Electrolyte allows rheological tuning for different printing methods

Abstract

Organic Electrochemical Transistors (OECTs) stand out for their interplay between ionic and electronic conduction, making them ideal analogues to biological synapses for neuromorphic computing and biosensing applications. Furthermore, they can be printed into integrated circuits on flexible substrates, enabling low-cost and high-throughput fabrication of complete electronic systems. However, most OECT electrolytes for integrated circuits still lack biocompatibility and suffer from rheology-related printing challenges. This paper presents a novel material basis that can be combined with an ionic liquid to fabricate an electrolyte for OECTs that only contains biocompatible materials. It allows rheological adjustments to enable the use of electrolyte in both inkjet and screen printing. Furthermore, the electrolyte is UV-curable, enabling it to transition into solid-state structures after printing. Extended ink and device lifetimes for screen-printed structures enable the fabrication of advanced OECTs that can operate in ambient air for over 30 days after fabrication. Ultimately, a fully screen-printed transistor using only biocompatible materials on a leaf substrate is shown