Modeling Sensing in Organic Electrochemical Transistors

Organic Electrochemical Transistors are seen as a key element for a fully flexible and wearable sensor technology. Their extremely large transconductance facilitates an inherent amplification of minute changes in the chemical environment yielding large sensitivities.

However, although sensing in OECTs is well established, many fundamental questions about the sensing and amplification mechanism remain unanswered. In order to facilitate further progress in the field, an experimentally verified device model is needed that is capable of predicting changes in the electrical response of OECTs in response to varying analyte levels.

Here, we discuss our progress towards such a model. Building on a 2D drift-diffusion model, we discuss the influence of electrolyte on the threshold voltage of the transistor. In addition, faradaic reactions are introduced in the model, enabling simulations of voltage-driven processes that are usually behind countless sensing applications. Lastly, an outlook is given towards scaling laws of sensors essential for an optimization of sensors, in particular their response time and sensitivity.