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Atomic study of molecular wires composed of thiophene oligomers
Author(s) -
Bai P.,
Li E. P.,
Ong E. A.,
Collier P.,
Loh K. P.
Publication year - 2007
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.200675302
Subject(s) - thiophene , oligomer , molecular wire , conductance , molecular orbital , density functional theory , materials science , alkyl , chemistry , computational chemistry , chemical physics , molecule , polymer chemistry , condensed matter physics , organic chemistry , physics
In this paper, we study the electron conductance of thiophene oligomers based molecular wires through atomic structures using the first principles method based on density functional theory and nonequilibrium Green's function. The molecular wires are built by sandwiching various thiophene oligomers between two metal electrodes via terminal groups at atomic levels. The effects of alkyl substituents on the thiophene oligomers are modelled by varying inter‐ring angles of the oligomers. Thiophene dimers, tetramers and hexamers are used to studied thiophene size effects. The projected orbitals, energy gaps, transmission functions and current–voltage characteristics of the molecular wires are calculated and analyzed. Results show that the molecular wires with the planar structures of thiophene oligomers have larger electron transmission functions, hence better electronic conductance than those with twist structures. The conductance of molecular wires decreases when the chain length of the thiophene oligomer increases. The results can provide guidance for design of thiophene molecular electronic wires and other devices. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)