The Non-Ideal Organic Electrochemical Transistors Impedance

TL;DR

This paper develops a distributed element impedance model for organic electrochemical transistors, accounting for non-ideal behaviors caused by device and material complexities across a wide frequency range, enhancing understanding and performance optimization.

Contribution

It introduces a new impedance model that incorporates three main deviations from ideality, providing a detailed understanding of OECT behavior under various conditions.

Findings

Model accurately fits impedance data over 1 Hz to 1 MHz

Identifies key deviations from ideality in OECTs

Provides insights for improving device performance

Abstract

Organic electrochemical transistors offer powerful functionalities for biosensors and neuroinspired electronics, with still much to understand on the time dependent behavior of this electrochemical device. Here, we report on distributed element modeling of the impedance of such microfabricated device, systematically performed under a large concentration variation for KCl(aq) and CaCl2(aq). We propose a new model which takes into account three main deviations to ideality, that were systematically observed, caused by both the materials and the device complexity, over large frequency range (1 Hz to 1 MHz). More than introducing more freedom degree, the introduction of these non redundant parameters and the study of their behaviors as function of the electrolyte concentration and applied voltage give a more detailed picture of the OECT working principles. This optimized model can be further useful for improving OECT performances in many applications (e.g. biosensors, neuroinspired devices) and circuit simulations.