Modeling Non-Equilibrium Ion-Transport in Ion-Selective-Membrane/Electrolyte Interfaces for Electrochemical Potentiometric Sensors

We present an approach to simulate ion’s drift and diffusion in chemical sensors based on ion-selective-membranes (ISMs) either ion-selective electrode structures or coupled field-effect transistors. The model is used analyze the sensitivity, selectivity, transient response of ISMs non-equilibrium conditions upon real-time concentration changes. Our simple implementation combines advanced features from semiconductor theory analytical electrochemistry, such as Schafetter-Gummel discretization scheme Chang-Jaffé boundary for ions at interfaces, thus allowing perform simulations beyond sensing. results are agreement with experimental responses reported literature. As relevant case studies, we examine ISM preconditioning miniaturized electrostatic interaction between FET channel ISMs. In first case, reveal that calibration curves performed incomplete conditioning can lead hysteretical when ion affinity electrolyte similar (e.g., organic ions). second find gate oxide field contact affects device characteristics concentrations not only change threshold voltage but also slope its IV curve. This effect be minimized by working subthreshold regime using extended gates.