Single-walled carbon nanotubes deposited on surface electrodes to improve interface impedance.

A suspension of commercially available single-walled carbon nanotubes (SWNTs) is directly deposited onto a platinum multielectrode array surface. This is a novel and easy method to reduce interface impedance values which can be used instead of electromodified electrodes. This paper shows that this deposition method is a useful technique for the modification of patterned electrodes ranging in the micro scale. A thorough comparison between the common and well-known black platinum versus SWNTs, as interface material for different electrode areas, has been carried out. SWNTs-based electrodes smaller than 40 microm Ø improve the interface impedance values when compared to black platinum-modified electrodes of the same size. The best results can be found for the 10 microm Ø, which improves the electrode resistance by 25% in comparison with the black platinum ones. The lower resistance and higher capacitance calculated for the 40 microm diameter SWNTs-based electrode, in comparison with black platinum, also evidence a clear increment of the effective area, which is directly related to the impedance decrease.