Improved adhesion of poly(3,4-ethylenedioxythiophene) (PEDOT) thin film to solid substrates using electrografted promoters and application to efficient nanoplasmonic devices

In this work we present a new strategy to enhance poly(ethylenedioxythiophene) (PEDOT) adhesion to solid substrates (Indium Tin Oxide-ITO and gold). Two derivatives, incorporating thiophene or ethylenedioxythiophene moieties, are first electrografted from diazonium salt precursors. The resulting ultrathin layers act as adhesion promoters for ITO and gold electrodes. In a second step, EDOT is electropolymerized on the modified surface. Adhesion tests, using ultrasonication, of the PEDOT layer deposited on bare or on modified ITO electrodes show that the presence of the ultrathin layer leads to an improvement of the PEDOT adhesion while retaining its electronic properties. This strategy was used to prepare stable plasmonic devices with gold nanoparticles surrounded by PEDOT film. We show that their plasmonic properties are not changed by the adhesion layer and that their lifetime are greatly improved.