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

Journal Article


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 for the modified electrodes, with a simplified Randles circuit applied to PEDOT-PSS and PEDOT-pTs and a Randles circuit including a Warburg impedance element for PEDOT-DBSA at 0 V. The impedance and phase angle at low frequencies using both equivalent circuit models is dependent on the electrode area. Low frequencies may therefore provide better predictions of the thermal noise and signal-to-noise ratio at modified electrodes. The coefficient of variation of the PEDOT-pTs impedance at low frequencies was lower than the other conducting polymers, consistent with linear and steady-state electroactive area measurements. There are poor correlations between the impedance and the charge density as they are not ideal metal electrodes.

Publication Date


  • 2015

Citation


  • Harris, A. R., Molino, P. J., Kapsa, R. M. I., Clark, G. M., Paolini, A. G. & Wallace, G. G. (2015). Correlation of the impedance and effective electrode area of doped PEDOT modified electrodes for brain-machine interfaces. The Analyst, 140 (9), 3164-3174.

Scopus Eid


  • 2-s2.0-84928345974

Ro Metadata Url


  • http://ro.uow.edu.au/aiimpapers/1399

Has Global Citation Frequency


Number Of Pages


  • 10

Start Page


  • 3164

End Page


  • 3174

Volume


  • 140

Issue


  • 9

Place Of Publication


  • United Kingdom

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 for the modified electrodes, with a simplified Randles circuit applied to PEDOT-PSS and PEDOT-pTs and a Randles circuit including a Warburg impedance element for PEDOT-DBSA at 0 V. The impedance and phase angle at low frequencies using both equivalent circuit models is dependent on the electrode area. Low frequencies may therefore provide better predictions of the thermal noise and signal-to-noise ratio at modified electrodes. The coefficient of variation of the PEDOT-pTs impedance at low frequencies was lower than the other conducting polymers, consistent with linear and steady-state electroactive area measurements. There are poor correlations between the impedance and the charge density as they are not ideal metal electrodes.

Publication Date


  • 2015

Citation


  • Harris, A. R., Molino, P. J., Kapsa, R. M. I., Clark, G. M., Paolini, A. G. & Wallace, G. G. (2015). Correlation of the impedance and effective electrode area of doped PEDOT modified electrodes for brain-machine interfaces. The Analyst, 140 (9), 3164-3174.

Scopus Eid


  • 2-s2.0-84928345974

Ro Metadata Url


  • http://ro.uow.edu.au/aiimpapers/1399

Has Global Citation Frequency


Number Of Pages


  • 10

Start Page


  • 3164

End Page


  • 3174

Volume


  • 140

Issue


  • 9

Place Of Publication


  • United Kingdom