title: The role of disorder on the electronic structure of conjugated polymers. The case of poly-2,5-bis(phenylethynyl)-1,3,4-thiadiazole.
abstract: Insight into the electronic structure of disordered poly-2,5-bis(phenylethynyl)-1,3,4-thiadiazole in an amorphous region, in comparison to an ideal two-planar cofacial oligomer system, is pursued. The atomic structure of the amorphous polymer was obtained from classical molecular dynamics. It was subsequently used to calculate the electronic states and inter- and intrachain electronic coupling integrals using the density functional theory based charge patching method. The interchain electronic coupling integrals in the amorphous system were found to be an order of magnitude smaller than in the ordered system with similar distances between the chains. The results also suggest that the electronic structure of the whole system cannot be understood as a collection of the electronic structures of individual chains. The band gap of the whole system is significantly smaller than the band gaps of individual chains. This decrease originates from the disordered long range electrostatic potential created by the dipole moments of polymer repeat units, which should be minimized if one seeks good transport properties.
authors: Department of Physical and Analytical Chemistry, University of Jaén, Campus Las Lagunillas s/n, 23071 Jaén, Spain.
authors: J M
authors: JM
authors: Granadino-Roldán
authors: Nenad
authors: N
authors: Vukmirović
authors: M
authors: M
authors: Fernández-Gómez
authors: Lin-Wang
authors: LW
authors: Wang
mesh_terms: D004583:Electrons; D008958:Models, Molecular; D015394:Molecular Structure; D011108:Polymers / Q000737:chemistry*; D011789:Quantum Theory; D013830:Thiadiazoles / Q000737:chemistry*
chemical_list: D011108:Polymers; D013830:Thiadiazoles