Spectroscopic analysis of structure in random poly(3-buthyl-co-3,4-dibuthylthiophene) copolymers.

Summary form only given. In the thiophene-based polymers a slight modification of the chemical structure may strongly influence the charge transport and the optical properties, as well as the processability and the environmental stability of the materials. We have prepared a series of alkyl substituted thiophene copolymers with the aim of modulate continuously the energy-gap value, the conjugation length and the optical properties in the series. The copolymers have been synthesized via FeCl/sub 3/ Oxidation and are composed of 3-buthylthiophene and 3,4 dibuthylthiophene units in different percentages. We present a spectroscopical study of these copolymers performed with NMR techniques combined with optical spectroscopies, such as Raman scattering and UV-Vis absorption. Aim of this work is to investigate the relationship between chemical structure of the copolymers and their electronic properties. NMR gives information on the copolymers composition as well as on the number and distribution of enchainment defects; the optical characterization, performed on the same samples allows us to monitor the conjugation length properties of these materials.