Current interdigitated microbands

FIGURE 4-30 Cyclic voltammogram for ferrocene at a 3 pm width, 2 pm gap interdigitated microband (solid line). The dotted line represents the current of the collector electrode held at a potential of —0.1 V (Reproduced with permission from reference 95.)... 

The major drawback of the technology of coplanar interdigitated microband electrodes is related to the fabrication technique the electrode materials are restricted to those that can be screen-printed and the voltage drop in the thin layer electrodes can be important, leading to non uniform overvoltage and current distributions [19]. Finally, the specific electrode areas developed by the interdigitated design are smaller than those developed with simple plane electrodes. 

Seddon BJ, Girault HH, Eddowes MJ (1989) Interdigitated microband electrodes chronotun-perometry and steady state currents. J Electroanal Chem 266 227—238... 

Applications for nano-gap electrodes are mainly focused on electroanalysis due to the considerable current amplification effect. The generator-collector system allows the possibility to sense redox systems to very low concentrations and therefore allude to applications in environmental and medicinal chemistry. Dam et al explored sensing applications at interdigitated microbands with 2 pm separation. The discrimination of dopamine and Fe(CN)6 oxidation was demonstrated. Amatore et al used potential pulses on double band electrodes in a microchannel as the generator-col-lector device to carry out time of flight measurements. Two methods were developed (i) generating a pulse followed by open circuit potential and... 

Nano-gap junction electrode devices also provide new types of measurement tools in biphasic redox systems. Ion transport across liquid liquid interfaces can be studied through the use of junction electrodes in generator collector mode. ° Vuorema et al utilised interdigitated microband electrodes for this purpose by depositing microdroplets of water-insoluble 4-(3-phenylpropyl)-pyridine with cobalt(II)phthalocyanine onto the electrodes which are then immersed into aqueous electrolyte solution. Both anion transfer across the liquid liquid interface and transport within the organic microdroplet phase were observed. The collector currents revealed the mobility of anions in the organic phase. More recently, also a... 

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