DFT and Raman/UV-Vis-NIR spectroscopic study of fused α-oligothiophenes with five and seven rings in neutral and doped states

We report the characterization of novel oligothienoacenes with five and seven fused thiophene rings; materials with potential applications in organic electronics. The compounds were investigated, both in their neutral and doped forms, by UV-Vis-NIR and FT-Raman spectroscopies. Density functional theory (DFT) calculations have been also performed to assess information regarding the minimum-energy molecular structure, atomic charges distribution, topologies and energies of the frontier molecular orbitals (MOs) around the gap, vibrational normal modes related to the main Raman features, and vertical one-electron excitations giving rise to the main optical absorptions.