Bilayers of drop casted C-60 fullerene films and electrochemically synthesized poly(3,4-ethylenedioxythiophene) (PEDOT) films have been studied. The PEDOT film was polymerised by cyclic voltammetry on top of the drop casted C-60 fullerene film. The bilayer films were produced and characterized in three different electrolytes; tetrabutylammoniumhexafluorophosphate (TBAPF(6)) and lithium hexafluorophosphate (LiPF6) in acetonitrile (ACN) and in the ionic liquid 1-butyl-3-methyl-imidazolium tetrafluoroborate (BMIMBF4). The bilayers were studied by cyclic voltammetry and in situ Fourier transform infrared attenuated total reflection (FTIR-ATR) spectroscopy. Both p- and n-doping of the bilayer films were studied and compared with PEDOT films prepared in organic media. (c) 2006 Elsevier Ltd. All rights reserved.