Multiphysics modeling of the electrochemical response of screen-printed electrodes for sensing applications

In this work, we present and validate a new 3-D COMSOL Multiphysics model capable of simulating the cyclic voltammetry (CV) and the electrochemical impedance spectroscopy (EIS) response of screen-printed devices. The proposed model considers the dominant electrical and electrochemical phenomena on the electrodes and in the electrolyte solution with redox reactions occurring at the metal/solution interface. The terminals of the simulated device are virtually connected to an equivalent circuit of a potentiostat in order to apply the potential and perform the CV readings with possibility to extend to other types of voltametric measurements. The model is calibrated on screen-printed devices through dedicated sets of experimental measurements that use CV and EIS with 10 mM [Fe(CN)6]3-/4- as redox mediator in phosphate-buffered saline (PBS) solution. The model parameters for each device are retrieved from the experimental measurements, e.g., double layer capacitance, red/ox diffusivity, elec...