Work

Rethinking organic electrochemical transistor modeling: the critical role of volumetric capacitance in predictive 2D Nernst-Planck-Poisson simulations

Year: 2025

Type: article

Abstract: Organic electrochemical transistors (OECTs) combine electron/ionic transport with organic semiconductor flexibility to connect biology and electronics. As they approach industrial use, optimizing performance requires accurate modeling of their structure. This study presents a two-dimensional (2D) OECT model based on Nernst–Planck–Poisson equations that explicitly includes volumetric capacitance (C V). Unlike previous models that ignore C V, our model highlights its essential role in OECT operation, allowing us to accurately match the measured output currents of PEDOT:PSS printed OECTs. We studied how parameters like diffusion coefficients of holes and ions, fixed anion concentration, and intrinsic capacitance affect transistor performance. We analyze existing OECT models, noting that different frameworks, despite varying assumptions, can reproduce data. This question relies solely on experimental agreement for validation. We argue that models should also be evaluated on their physical principles. To assist readers, we provide COMSOL.mph files for 1D and 2D OECT models for device design and optimization.

Source: npj Flexible Electronics

DOI: 10.1038/s41528-025-00482-9

Authors: Ihor Sahalianov, Aleksandar Y. Mehandzhiyski, Peter Andersson Ersman, Igor Zozoulenko

Institutions: Linköping University, RISE Research Institutes of Sweden, Wallenberg Wood Science Center

Language: English

Topic: Conducting polymers and applications

Subfield: Polymers and Plastics

Field: Materials Science

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $4,090

Funders: Linköpings Universitet, Vetenskapsrådet, Wallenberg Wood Science Center