Paper-supported nanostructured ultrathin gold film electrodes - Characterization and functionalization

Ultrathin gold films (UTGFs) were fabricated on a nanostructured latex-coated paper substrate by physical vapour deposition (PVD) with the aim to provide low-cost and flexible conductive electrodes in paper-based electronics. Morphological, electric and optical properties of UTGFs were dependent on the deposited film thickness. In addition, UTGFs were functionalized with insulating and hydrophobic 1-octadecanethiol self-assembled monolayer and inkjet-printed conductive and hydrophilic poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT-PSS) layer and their electrochemical properties were examined. Results showed that sufficient mechanical stability and adhesion of UTGFs deposited on latex-coated paper was achieved without the need on any additional adhesive layers, enabling a more robust fabrication process of the electrodes. UTGF electrodes tolerated extensive bending without adverse effects and conductivity comparable to the bulk gold was obtained already with the film thickness of 6 nm. Although not been fabricated with the high-throughput method like printing, a very low material consumption (∼12 μg/cm2) together with a high conductivity (resistivity < 3 × 10−6 Ω cm) makes the UTGFs electrodes potential candidates low-cost components in flexible electronics. In addition, the excellent stability of the UTGF electrodes in electrochemical experiments enables their application in the development of paper-based electrochemical platforms, e.g. for biosensing purposes.