Journal article

Correlation of the impedance and effective electrode area of doped PEDOT modified electrodes for brain-machine interfaces

Alexander R Harris, Paul J Molino, Robert MI Kapsa, Graeme M Clark, Antonio G Paolini, Gordon G Wallace

ANALYST | ROYAL SOC CHEMISTRY | Published : 2015

Abstract

Electrode impedance is used to assess the thermal noise and signal-to-noise ratio for brain-machine interfaces. An intermediate frequency of 1 kHz is typically measured, although other frequencies may be better predictors of device performance. PEDOT-PSS, PEDOT-DBSA and PEDOT-pTs conducting polymer modified electrodes have reduced impedance at 1 kHz compared to bare metal electrodes, but have no correlation with the effective electrode area. Analytical solutions to impedance indicate that all low-intermediate frequencies can be used to compare the electrode area at a series RC circuit, typical of an ideal metal electrode in a conductive solution. More complex equivalent circuits can be used ..

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