Critical Assessment on Modeling and Design of Nonfaradaic CMOS Electrochemical Sensing

To assist the design process of nonfaradaic electrochemical sensors in realistic biological media, we examine multiple types of sensing operations in polyelectrolytes. By comparing the quasi-static transconductance, impedance spectroscopy, and capacitance-voltage measurements, we assess the physical contributions from the double-layer composition, overall solution resistance, and sensing surface potential under various polyelectrolytic molarities. The mixture of NaCl and MgCl
₂
is chosen for illustration to provide insight into circuit model parameters for nonfaradaic sensing. Our finding also shed light on the dynamics of double-layer competition and correlation, which is critical for understanding the physical phenomena occurring at the sensing interface, and accurately interpreting sensor data.