Flexible complementary logic circuit built from two identical organic electrochemical transistors

TL;DR

This paper demonstrates a flexible complementary organic electrochemical transistor circuit using identical PANI-based OECTs, achieving high gain and aqueous operation, advancing bioelectronic device capabilities.

Contribution

It introduces a novel complementary circuit with identical PANI OECTs, overcoming stability issues and enabling flexible, aqueous bioelectronic applications.

Findings

Achieved a gain of approximately 7 in the PANI-based circuit.

Successfully transferred the circuit onto a flexible chitosan substrate.

Demonstrated stable operation in aqueous electrolyte.

Abstract

The organic electrochemical transistor (OECT) with a conjugated polymer as the active material is the elementary unit of organic bioelectronic devices. Increased functionalities, such as low power consumption, can be achieved by building complementary circuits featuring two or more OECTs. Complementary circuits commonly combine both p- and n-type transistors to reduce power draw. While p-type OECTs are readily available, n-type OECTs are less common mainly due to poor stability of the n-type active channel material in aqueous electrolyte. Additionally, an OECT based complementary circuit requires well matched transport properties in the p- and n-type materials. Here, a complementary circuit is made using a pair of OECTs having polyaniline (PANI) as the channel material in both transistors. PANI is chosen due to its unique behaviour exhibiting a peak in current versus gate voltage when used as an active channel in an OECT. The PANI based circuit is shown to have excellent performance with gain of ~ 7 and could be transferred on a flexible biocompatible chitosan substrate with demonstrated operation in aqueous electrolyte. This study extends the capabilities of conjugated polymer based OECTs.