Exploring the electronic structure of an organic semiconductor based on a compactly fused electron donor-acceptor molecule.
A Mott-type semiconductor based on a compactly fused and partially oxidized electron donor-acceptor (D-A) molecule was recently prepared and identified to exhibit a large room-temperature conductivity of 2 S cm(-1) . In a marked contrast to the organic conductors characterized by relatively well decoupled and segregated uniform stacks of D and A moieties, the formally half-oxidized tetrathiafulvalene donors of the actual compound are organized in columnar π stacks only, whereby the coplanar electron-acceptor units, namely benzothiadiazole, are closely annulated along their ridges. Herein, we present a theoretical study that explores the electronic structure of this novel type of organic semiconductor. The highly symmetric-solid state material behaves as a one-dimensional electronic system with strong antiferromagnetic interactions (coupling constant>200 cm(-1) ). The unique shape and local dipole of this redox-active fused electron D-A molecule lays the basis for further investigations of the collective electronic structure, mainly in the function of different counterions embedded in the crystalline lattice.
Departament de Química Física and Institut de Química Teórica i Computacional (IQTCUB), Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona (Spain).
Pere
P
Alemany
Institut de Ciència de Materials de Barcelona (CSIC), Campus de la UAB, 08193 Bellaterra (Spain). canadell@icmab.es.
Enric
E
Canadell
Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern (Switzerland).
Yan
Y
Geng
Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern (Switzerland).
Jürg
J
Hauser
Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern (Switzerland).
Piero
P
Macchi
Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern (Switzerland).
Karl
K
Krämer
Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern (Switzerland).
Silvio
S
Decurtins
Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern (Switzerland). liu@dcb.unibe.ch.
Shi-Xia
SX
Liu
density functional calculations; donor-acceptor systems; electronic structure; organic semiconductors; tetrathiafulvalene-benzothiadiazole