Flexible optically transparent single-walled carbon nanotube electrodes for UV–Vis absorption spectroelectrochemistry

We present a simple and reproducible method to produce single-walled carbon nanotube (SWCNT) optically transparent electrodes (OTEs) for optical transmission spectroelectrochemistry on flexible and insulating Polyethylene terephthalate (PET) supports. SWCNTs grown by aerosol chemical vapor deposition (CVD) and collected directly from the gas phase on filters were transferred to PET substrates by simple pressing the filter against PET. Despite their high transparency (up to 92% transmittance at 550 nm), the resulting SWCNT/PET/OTEs exhibited excellent electrochemical properties for a series of redox couples covering a wide potential window. For low density SWCNT networks, the electroactive surface area calculated from the voltammetric response represents roughly the whole surface coverage of SWCNTs as determined by FESEM. Highly transparent SWCNT/PET/OTEs also showed very good performance for Ru(bipy)33+/2+ spectroelectrochemistry, enabling an accurate estimation of characteristic electrochemical parameters for this redox couple.