Signal amplification properties of Electrolyte-Gated Organic Field-Effect Transistors

Electrolyte-gated organic field-effect transistors (EGOFETs) are key enabling elements for the development of bio-electronic devices, therefore it is imperative to increase the knowledge on how EGOFETs work, not only in stationary conditions but also in the time and frequency domain. In this framework, the EGOFET small-signal circuit is presented and the recording of action potentials (APs) is simulated by analyzing EGOFETs as trans-conductance amplifiers as well as voltage amplifiers. It is shown that when operating as a trans-conductance amplifier, EGOFETs ideally allow to well preserve the shape of the recorded AP but they amplify high-frequency noise thus heavily worsening the signal-to-noise ratio (SNR). Whereas, when implemented in a voltage amplifier, EGOFETs allow a substantial SNR improvement, but introduce some distortion in the recorded signal.