Optimization of organic electrochemical transistors for sensor applications

TLDR

Despite recent interest in OECTs as chemical and biological sensors, little is known about how device architecture and material parameters affect sensor performance. Numerical modeling shows that ion‑to‑electron conversion is optimized by using a gate electrode larger than the channel or a nonpolarizable gate, while higher polymer conductivity and a wide, thick, short channel further boost response; for electrochemical sensing, sensitivity peaks when the gate is smaller than the channel and is enhanced by higher carrier mobility, greater capacitance per area, better ion penetration, and a wide, short channel geometry. © 2010 Wiley Periodicals, Inc.

Abstract

Abstract Despite the recent interest in organic electrochemical transistors (OECTs) as chemical and biological sensors, little is known about the role that device architecture and materials parameters play in determining sensor performance. We use numerical modeling to establish design rules in two regimes of operation: We find that for operation as an ion‐to‐electron converter, the response of OECTs is maximized through the use of a gate electrode that is much larger than the channel or through the use of a nonpolarizable gate electrode. Improving the conductivity of the polymer and using a channel geometry that maximizes channel width and thickness, and minimizes channel length helps increase the response. For operation as an electrochemical sensor, the sensitivity is maximized in OECTs with gate electrodes that are smaller than their channels. The sensitivity can be improved by increasing the charge carrier mobility and the capacitance per unit area of the conducting polymer, and also its ability to be penetrated by ions from the electrolyte. A channel geometry that maximizes channel width and minimizes channel length also improves sensitivity. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2010