Theory of Potential Step Chronoamperometry at a Microband Electrode: Complete Explicit Semi-Analytical Formulae for the Faradaic Current Density and the Faradaic Current

Bieniasz, Lesław K.

doi:10.1016/j.electacta.2015.07.040

Cited by 14 publications

(4 citation statements)

References 31 publications

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“…The τ represents a dimensionless parameter defined by the product of diffusion coefficient, time, and inverse of width squared. Bieniasz 62,71 previously presented CA simulations exhibiting currents close to those predicted by Eq. 3 for τ values of 10 −15 to 10 25 .…”

Section: Resultssupporting

confidence: 57%

In Situ and 2D and 3D in Silico Redox Cycling Studies for Design Optimization of Coplanar Arrays of Microband Electrodes in a 70 μm × 100 μm Electroactive Footprint

Abrego Tello,

Lotfi Marchoubeh,

Fritsch

2024

J. Electrochem. Soc.

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Optimization of redox-cycling currents was performed by adjusting the height (sidewalls, h), width (w) ,and length (l) of band electrodes and their spacing (wgap) in coplanar arrays restricted to a small-electroactive window of 70 × 100 µm. These arrays can function in µL-volumes for chemical analysis (e.g., in vivo dopamine detection using probes). Experiments were conducted with an array of five electrodes (NE = 5), w = 4.3 µm, wgap = 3.7 µm, h = 0.150 µm, and l = 99.2 µm. Reasons for disparities between currents from experiments and approximate equations were determined by high-density mesh simulations and were found to arise from sluggish heterogeneous electron transfer kinetics and diffusion at electrode ends, edges, and heights. Ferricyanide, with its moderately slow kinetics, exhibits redox-cycling currents that fall below predictions by the equations as wgap decreases and diffusional flux outpaces reaction rates. Simulations aid investigations of various array designs, achievable through conventional photolithography, by decreasing w and wgap and increasing NE to fit within the electroactive window. A coplanar array, NE = 58, w = wgap = 0.6 µm, h = 0.150 µm and l = 100 µm, yielded ferricyanide sensitivities of 0.266, 0.259 nA·µM−1, enhancements of 8× and 9× over w = wgap = 4 µm, and projected dopamine limits of quantification of 139 nM, 171 nM at generator and collector electrodes, respectively

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Section: Resultssupporting

confidence: 57%

In Situ and 2D and 3D in Silico Redox Cycling Studies for Design Optimization of Coplanar Arrays of Microband Electrodes in a 70 μm × 100 μm Electroactive Footprint

Abrego Tello,

Lotfi Marchoubeh,

Fritsch

2024

J. Electrochem. Soc.

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“…It is not possible to solve (24) explicitly without assuming a specific electrode configuration, but we can estimate the impedance…”

Section: A Sinusoidal Waveformsmentioning

confidence: 99%

“…However, without analytical description, fitting the numerical results to the RC approximations provides only a limited understanding of the transition, let alone that such finiteelement models are usually intractable for an arbitrary electrode geometry. Nevertheless, the results have been widely adopted in practical applications [22][23][24][25]. In this paper, we present a general model of the transition from the primary current distribution to PCD for any electrode geometry and material composition, while considering the effects of the supercapacitance, the electrode kinetics and the ohmic drop.…”

Section: Introductionmentioning

confidence: 99%

Current Distribution on Capacitive Electrode-Electrolyte Interfaces

Chen¹,

Ryzhik²,

Palanker³

2020

Phys. Rev. Applied

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The distribution of electric current on an electrode surface in electrolyte varies with time due to charge accumulation at a capacitive interface, as well as due to electrode kinetics and concentration polarization in the medium. Initially, the potential at the electrode-electrolyte interface is uniform, resulting in a non-uniform current distribution due to the uneven ohmic drop of the potential in the medium. Over time, however, the non-uniform current density causes spatially varying rate of the charge accumulation at the interface, breaking down its equipotentiality. We developed an analytical model to describe such transition at a capacitive interface under the mass-transfer limiting current, and demonstrate that the steady distribution of the current is achieved when the current density is proportional to the capacitance per unit area, which leads to linear voltage ramp at the electrode. More specific results regarding the dynamics of this transition are provided for a disk electrode, along with an experimental validation of the theoretical result. These findings are important for many electrochemical applications, and in particular, for proper design of the electro-neural interfaces.

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“…One approach is use to the finite element method (FEM) to give accurate numerical solutions, and its implementation in the program Comsol Multiphysics R°[ 2] has found wide use in electrochemistry [3]. Another approach to accurate solutions is to use semianalytic methods, which have recently been used for band electrodes with and without flow [4][5][6]. More commonly, approximations are applied to get simplified analytical expressions: (i) axial diffusion (in the channel direction) is neglected, and/or (ii) the Lévêque approximation is applied, i.e., the velocity profile is assumed to be linear.…”

Section: Introductionmentioning

confidence: 99%

Mass-transport impedance at channel electrodes: accurate and approximate solutions

Holm

Ingdal

Fanavoll

et al. 2016

Electrochimica Acta

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Theory of Potential Step Chronoamperometry at a Microband Electrode: Complete Explicit Semi-Analytical Formulae for the Faradaic Current Density and the Faradaic Current

Cited by 14 publications

References 31 publications

In Situ and 2D and 3D in Silico Redox Cycling Studies for Design Optimization of Coplanar Arrays of Microband Electrodes in a 70 μm × 100 μm Electroactive Footprint

In Situ and 2D and 3D in Silico Redox Cycling Studies for Design Optimization of Coplanar Arrays of Microband Electrodes in a 70 μm × 100 μm Electroactive Footprint

Current Distribution on Capacitive Electrode-Electrolyte Interfaces

Mass-transport impedance at channel electrodes: accurate and approximate solutions

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