Regular arrays of microdisc electrodes: simulation quantifies the fraction of ‘dead’ electrodes

Ordeig, Olga; Banks, Craig E.; Davies, Trevor J.; Campo, F. Javier del; Mas, Roser; Muñoz, Francesc Xavier; Compton, Richard G.

doi:10.1039/b513786a

Cited by 60 publications

(55 citation statements)

References 12 publications

(21 reference statements)

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“…Therefore an easier approach is to use a simulation method, the details of which have been described elsewhere. [12][13][14] Comparison of experimental data with numerical simulations revealed that the actual number of discs on the array corresponds to 170 and 1550 electrodes for array 1 and array 2, respectively (see Table 1). …”

Section: Characterization Of the Ultra-microelectrode Arraysmentioning

confidence: 99%

“…The only way to quantitatively determine the actual number of electrodes on the array is to either i) electrochemically plate copper metal on the array so that they can be physically counted or ii) fit several cyclic voltammograms for the ferrocyanide/ ferricyanide couple as a function of scan rate with that predicted via theory. 13 Given that the array in this example has over 2000 electrodes, option i) would be tedious and time consuming. Therefore an easier approach is to use a simulation method, the details of which have been described elsewhere.…”

Section: Characterization Of the Ultra-microelectrode Arraysmentioning

confidence: 99%

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Gold Ultra-microelectrode Arrays: Application to the Steady-State Voltammetry of Hydroxide Ion in Aqueous Solution

et al. 2006

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Experimental Reagents and instrumentationPotassium chloride (KCl), potassium hexacyanoferrate(II) (K4Fe(CN)6), sodium sulfate anhydrous (Na2SO4) and sodium hydroxide (NaOH) were purchased from Panreac. All chemicals were analytical reagent grade. Gold ultra-microelectrode arrays are used to explore the electrochemical oxidation of hydroxide ions and are shown to be analytical useful. Two types of ultra-microelectrode arrays are used; the first consist of 256 individual electrodes of 5 µm in radius, 170 of which are electrochemically active in a cubic arrangement which are separated from their nearest neighbour by a distance of 100 µm. The second array compromises 2597 electrodes of 2.5 µm in radius and of which 1550 of which are electrochemically active in a hexagonal arrangement separated by the nearest neighbour by 55 µm.Well defined voltammetric waves are found with peak currents proportional to the concentration of hydroxide ions in the range 50 µM to 1 mM. Detection limits of 20 µM using the 170 ultra-microelectrode and 10 µM with the 1550 ultramicroelectrode array are shown to be possible but with a higher sensitivity of 4 mA M -1 observed using the 1550 ultramicroelectrode array compared to 1.2 mA M -1 with the 170 ultra-microelectrode array.

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Section: Characterization Of the Ultra-microelectrode Arraysmentioning

confidence: 99%

Section: Characterization Of the Ultra-microelectrode Arraysmentioning

confidence: 99%

Gold Ultra-microelectrode Arrays: Application to the Steady-State Voltammetry of Hydroxide Ion in Aqueous Solution

et al. 2006

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“…The fraction of the active electrodes is 20% which is less than the typical value of active electrodes in conventional microdisk electrodes arrays. 41,44 This is due to deficiencies in the final etching step of the fabrication process. Presumably, due to slight inhomogeneities in oxide layer thicknesses, the reactive ion etching has not been able to open all the microdisks and hence the low active number.…”

Section: Experimental Validationmentioning

confidence: 99%

Microarrays of Ring-Recessed Disk Electrodes in Transient Generator-Collector Mode: Theory and Experiment

et al. 2009

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The fabrication, characterisation and use of arrays of ring-recessed disk microelectrodes is reported. This devices are operated in generator-collector mode with a disc acting as generator and the ring as the collector. We report experiments and simulations relating to time of flight experiments in which material electrogenerated at a disc is diffusionally transported to the ring. Analysis of the current transient measured at the latter when it is potentiostatted at a value to ensure diffusionally controlled "collection" is shown to sensitively reflect the diffusion coefficients of the species forming the redox couple being driven at the generator electrode. The method is applied to the ferrocene/ferrocenium couple in the room temperature ionic liquid [N 6,2,2,2 ][NTf 2 ] and the results found to agree with independent measurements.

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“…Nanoelectrode arrays were fabricated over gold microband electrodes that had previously been made using standard photolithographic techniques as described previously in 12,13 . Chips containing gold microbands were spin-coated with a 100nm layer of PMMA 950K.…”

Section: Fabrication Of Disk Nanoelectrode Arraysmentioning

confidence: 99%

Mass Transport to Nanoelectrode Arrays and Limitations of the Diffusion Domain Approach: Theory and Experiment

et al. 2009

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RECEIVED DATE (to be automatically inserted after your manuscript is accepted if requiredaccording to the journal that you are submitting your paper to) CORRESPONDING AUTHOR FOOTNOTE. F. Javier del Campo. Tel.: +34-935.947.700; Fax number: +34-935.801.496. 2ABSTRACT. The diffusion domain approach is a general framework for the understanding, interpretation and prediction of the response of microelectrode arrays. This work exposes some of its limitations, particularly when dealing with nanoelectrode arrays of a few microns in size. This article provides an overview of the principles and assumptions underpinning the diffusion domain approach, and then applies it to the study of nanoelectrode arrays. The apparent disagreement between theory and experimental data, due to the importance of radial diffusion to nanoelectrode arrays compared to microelectrode arrays, is explained using simulations and experiments. The principle that an array of micro-or nano-electrodes eventually behaves as if the entire array were a single electrode of the size of the array, with its corresponding properties, applies always. However, while microelectrode arrays tend to behave as macroelectrodes, nanoelectrode arrays on the other hand may behave as microelectrodes.For the case of arrays of small numbers of electrodes, or array sizes of microns or less in size, this compromises one of the key assumptions of the diffusion domain approach, namely that inner electrodes in an array are equivalent, which may lead the unaware to erroneous conclusions.

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Regular arrays of microdisc electrodes: simulation quantifies the fraction of ‘dead’ electrodes

Cited by 60 publications

References 12 publications

Gold Ultra-microelectrode Arrays: Application to the Steady-State Voltammetry of Hydroxide Ion in Aqueous Solution

Gold Ultra-microelectrode Arrays: Application to the Steady-State Voltammetry of Hydroxide Ion in Aqueous Solution

Microarrays of Ring-Recessed Disk Electrodes in Transient Generator-Collector Mode: Theory and Experiment

Mass Transport to Nanoelectrode Arrays and Limitations of the Diffusion Domain Approach: Theory and Experiment

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