Optical and Electrical Properties of Gold Nanoparticles/Poly(3-alkylthiophene) Composites

We report on the optical and electrical properties of nanocomposite materials based on poly(3-hexylthiophene), P3HT, or poly(3-octylthiophene), P3OT, blended with gold nanoparticles (2.6±1.2 nm) up to the Au content 5.7 vol%. The (polyalkylthiophene)/Au nanocomposites are easily processable, film-forming temperature-stable materials. The optical spectra analysis and the X-ray diffraction show a decrease in the crystalinity of the poly(alkylthiophene)/Au thin films in comparison with the neat polymer. At lower temperatures, the electrical conductivity of the nanocomposites is thermally activated and depends exponentially on the distance of the nanoparticles as in the case of 3D nanoparticle arrays. At higher temperatures, the conductivity passes a maximum whose position varies from 70 °C and 80 °C in the neat P3OT and P3HT, respectively, to approx. 100 °C in the case of the nanocomposites. The shift of the conductivity maximum has been related to the changes in the polymer morphology introduced by the presence of the nanoparticles.