Finite Element Modeling of Nanopore Geometry in Microelectrode Arrays to Enhance the Sensitivity of Electrochemical Sensors
Document Type
Conference Proceeding
Publication Date
11-14-2025
Department
Department of Electrical and Computer Engineering
Abstract
We present a finite element modeling study to optimize nanopore geometry in microelectrode arrays to enhance sensitivity in electrochemical sensing. Each 10β―Β΅m diameter electrode comprises a Cr/Au thin film on a fused silica substrate, conformally coated with an ππ’ππ layer that introduces surface defects acting as nanopores. The array consists of seven electrodes arranged in a hexagonal close-packed (HCP) configuration. To minimize crosstalk between adjacent electrodes, the spacing was optimized to ensure a 90% reduction in electric field strength at the nearest neighbor, resulting in inter-electrode distances greater than 9β―Β΅m. The electrochemically active area is defined by separate, 0.6β―Β΅m-deep epoxy resin wells(each containing a single nanopore with different pore radius) patterned on top of the ππ’ππ layer. The epoxy resin wells were filled with 20β―mM Potassium Ferrocyanide (ππ [π π (ππ)π]) and 0.5β―M Potassium Chloride (KCl) as the supporting electrolyte. Redox reactions occur at the exposed Au surface at the base of each nanopore. To optimize pore geometry, we swept the ππ’ππ thickness which definiens the pore height (depth) from 5β―nm to 20β―nm in 150 steps, measuring the resulting diffusion-limited current. This analysis was conducted across five different pore radiiβ10, 20, 50, 80, and 100β―nmβ in separate epoxy resin wells, to construct a comprehensive performance map. The highest diffusion-limited current, ~3β―nA, was observed at a pore radius of 80β―nm and height of 11.8β―nm, corresponding to an optimal r/h ratio of 6.77. Notably, only the 10β―nm pore exhibited non-classical transport behavior caused by electric double layer overlap. These findings provide practical design guidelines for development of high resolution, multi-electrode single-entity electrochemical detection platforms.
Publication Title
2025 IEEE 20th Nanotechnology Materials and Devices Conference (NMDC)
Recommended Citation
Eskandari, P.,
&
Bergstrom, P.
(2025).
Finite Element Modeling of Nanopore Geometry in Microelectrode Arrays to Enhance the Sensitivity of Electrochemical Sensors.
2025 IEEE 20th Nanotechnology Materials and Devices Conference (NMDC).
http://doi.org/10.1109/NMDC64551.2025.11234600
Retrieved from: https://digitalcommons.mtu.edu/michigantech-p2/2581