Electrode fabrication at liquid interfaces: Towards transparency and flexibility

We demonstrate here the huge potential of liquid/liquid interfaces to process different kinds of materials as thin films, aiming for the preparation and modification of electrodes, specifically focusing on transparent and flexible ones. As a proof-of-concept, we prepared single-walled carbon nanotubes films at water/chloroform interfaces and deposited over ordinary poly(ethylene terephthalate) (PET) substrates, yielding stable, robust, transparent, and flexible electrodes. The transmittance and the conductivity of the electrodes were controlled by tuning simple experimental parameters, illustrating the broadness of the method. The electrochemical performance of the electrodes was evaluated towards ferro/ferricyanide redox pair, and their real application in a classical electrochemical deposition of metallic copper. Afterwards, the potentiality of the liquid/liquid interfacial route to modify electrodes was demonstrated by depositing a thin and transparent film of polyaniline, in which the electrochromic properties were displayed. Finally, the construction and performance of symmetric, transparent, and flexible supercapacitor devices based on the polyaniline-modified electrodes were presented.