title: Combined quantum chemical density functional theory and spectroscopic Raman and UV-vis-NIR study of oligothienoacenes with five and seven rings.
abstract: In this article, we report the characterization of novel oligothienoacenes with five and seven fused thiophene rings, materials with potential applications in organic electronics. In contrast to usual alpha-linked oligothiophenes, these fused oligothiophenes have a larger band gap than most semiconductors currently used in the fabrication of organic field-effect transistors (OFETs) and therefore they are expected to be more stable in air. The synthesis of these fused-ring oligomers was motivated by the notion that a more rigid and planar structure should reduce defects (such as torsion about single bonds between alpha-linked units or S-syn defects) and thus improve conjugation for better charge-carrier mobility. The conjugational properties of these two molecular materials have been investigated by means of FT-Raman spectroscopy, revealing that conjugation still increases in passing from the five-ring oligomer to that with seven-rings. DFT and TDDFT quantum chemical calculations have been performed, at the B3LYP/6-31G level, to assess information regarding the minimum-energy molecular structure, topologies, and absolute 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.
authors.affiliation: Department of Physical Chemistry, University of Malaga, 29071-Malaga, Spain.
authors.forename: Reyes Malavé
authors.initials: RM
authors.lastname: Osuna
authors.forename: Xinnan
authors.initials: X
authors.lastname: Zhang
authors.forename: Adam Jay
authors.initials: AJ
authors.lastname: Matzger
authors.forename: Víctor
authors.initials: V
authors.lastname: Hernandez
authors.forename: Juan Teodomiro
authors.initials: JT
authors.lastname: López Navarrete