In situ synthesis and deposition of conducting PEDOT:PSS nanospheres on ITO-free flexible substrates

In this paper we report a novel oxidant- and etching-free process for the preparation of conducting poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) nanocomposite layers through thermal debromination polymerization; it involves depositing a solution of 2,5-dibromo-3,4-ethylenedioxythiophene (DBEDOT) and PSS in MeOH/H2O onto a flexible poly(ethylene terephthalate) (PET) substrate heated at 120 °C. SEM and TEM images revealed that the surface of the conducting PEDOT:PSS film featured PEDOT nanospheres wrapped in a coating of PSS. The Raman spectrum of the PEDOT:PSS nanosphere layer featured a signal for symmetrical stretching at 1450-1434 cm−1; this vibration was sensitive to oxidizing (doping) and reducing (de-doping) behavior. This strategy has potential use in roll-to-roll processing of flexible organic optoelectronic devices.