Nernst-Planck-Poisson analysis of electrolyte-gated organic field-effect transistors

Abstract

Electrolyte-gated organic field-effect transistors (EGOFETs) represent a class of organic thin-film transistors suited for sensing and biosensing in aqueous media, often at physiological conditions. The EGOFET device includes electrodes and an organic semiconductor channel in direct contact with an electrolyte. Upon operation, electric double layers are formed along the gate-electrolyte and the channel-electrolyte interfaces, but ions do not penetrate the channel. This mode of operation allows the EGOFET devices to run at low voltages and at a speed corresponding to the rate of forming electric double layers. Currently, there is a lack of a detailed quantitative model of the EGOFETs that can predict device performance based on geometry and material parameters. In the present paper, for the first time, an EGOFET model is proposed utilizing the Nernst-Planck-Poisson equations to describe, on equal footing, both the polymer and the electrolyte regions of the device configuration. The generated calculations exhibit semi-qualitative agreement with experimentally measured output and transfer curves. ; Funding Agencies|Swedish Research CouncilSwedish Research CouncilEuropean Commission [2017-04474]; Swedish Government Strategic Research Area in Materials Science on Advanced Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009-00971]; French National Research Agency (Agence Nationale de la Recherche) through the project EGOFLEXFrench National Research Agency (ANR) [ANR-17-CE08-0025]