Optical, structural and electrical properties of polyaniline systems doped with C60 and small gap C60 fullerenes

In this work two systems consisting on polyaniline (Pani) doped with simple and small gap C60 fullerenes have been prepared and characterized. Composites with different doping amounts of 1,2,4 and 8 wt% have been analyzed in order to evaluate their structure together with their optical and electrical properties and the effect of fullerene type and amount on them. The shift and change of shape in Fourier transform infrared spectroscopy (FTIR) bands and solid 13C NMR spectroscopy signals showed the presence of interactions between matrix and fullerenes by electron density transfer among them. Optical properties have also been analyzed in terms of ultraviolet (UV) spectroscopy. The blue shift of several bands confirmed the charge transfer. Obtained structures have been analyzed by optical microscopy (OM) showing the different way in which both types of fullerenes have been incorporated into the polymer chains. Finally, conductivity has been measured by the four probe technique, relating obtained values with the structure of the composite and the different degree of crystallinity of simple and small gap fullerenes.