The Role of Relative Capacitances in Impedance Sensing with Organic Electrochemical Transistors

The organic electrochemical transistor (OECT) has attracted interest for use in biosensor technology due to its ability transduce ionic electronic signals and operate aqueous environments. While OECTs have been broadly applied biosensing impedance characterization of biological systems, there is still no consensus on the ideal geometries, relative capacitances, operational conditions specific sensing scenarios. Here it shown that with a capacitive layer gate, gate-limited produce largest sensor response. An equivalent circuit model used study frequency response non-permeable ion-permeable membranes added gate found configuration, respect channel able signal determined by capacitance be sensed as well membrane permeability. findings are design gold OECT capable detecting formation lipid bilayer gate. results indicate high transconductance typically considered attractive do not deliver when sensing. Results presented settings similar those practical experiments, thereby providing guidance how best biosensing.