title: Thiophene- and selenophene-based heteroacenes: combined quantum chemical DFT and spectroscopic Raman and UV-Vis-NIR study.
abstract: In this article, we report the characterization of a series of thiophene- and selenophene-based heteroacenes, materials with potential applications in organic electronics. In contrast to the usual alpha-oligothiophenes, these annelated oligomers 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 molecular materials 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 pi-conjugation for better charge-carrier mobility. The conjugational properties of these heteroacenes have been investigated by means of FT-Raman spectroscopy, revealing that pi-conjugation increases with the increasing number of annelated 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 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 Málaga, 29071-Málaga, Spain.
authors.forename: Reyes Malavé
authors.initials: RM
authors.lastname: Osuna
authors.forename: Rocío
authors.initials: R
authors.lastname: Ponce Ortiz
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Okamoto
authors.forename: Yoshitake
authors.initials: Y
authors.lastname: Suzuki
authors.forename: Shigehiro
authors.initials: S
authors.lastname: Yamaguchi
authors.forename: Víctor
authors.initials: V
authors.lastname: Hernandez
authors.forename: Juan Teodomiro
authors.initials: JT
authors.lastname: López Navarrete