OPTICAL ANISOTROPY OF NEUTRAL AND DOPED POLY(3-OCTYLTHIOPHENE)

The anisotropy of the optical absorption of highly oriented poly(3-octylthiophene) have been measured. By stretching polyethylene foils, spin coated with poly(3-octylthiophene), P3OT, highly oriented, thin films of P3OT can be produced. The degree of orientation of these films was determined by infra-red dichroic measurements. The orientation as expressed by the orientation function was 0.82. This information was used together with the optical ansisotropy data to estimate the intrinsic anisotropy of the absorption coefficient. An anisotropy ratio about 10 for the absorption coefficients parallel and perpendicular to the chain axis was estimated. In lightly doped samples the anisotropy was much higher than in neutral and highly doped samples. Tentative explainations for the observed anisotropy values are given. © 1990.