A theoretical model for the time varying current in organic electrochemical transistors in a dynamic regime

The dynamic interaction between cations and doped conductive polymer is at the basis of the working principles of organic electrochemical transistor devices. In this letter, we describe a theoretical model for the transport of saline ions in an electrolyte under the influence of an external voltage in a dynamic regime. We show how this scheme can be used to derive the time varying response and current generated by a conductive PEDOT:PSS polymer based OECT device interacting with those ions. The simulated output of the system displays a very high sensitivity on the parameters of the process including charge, size and concentration of the ions, and the frequency of operation of the device. The proposed model can be used to analyze the activity of an OECT device to derive the physical characteristics of individual species in a solution.