Accurate method for obtaining band gaps in conducting polymers using a DFT/hybrid approach

Date
1998
Authors
Salzner, U.
Pickup, P. G.
Poirier, R. A.
Lagowski, J. B.
Advisor
Supervisor
Co-Advisor
Co-Supervisor
Instructor
Source Title
Journal of Physical Chemistry A
Print ISSN
1089-5639
Electronic ISSN
Publisher
American Chemical Society
Volume
102
Issue
15
Pages
2572 - 2578
Language
English
Type
Article
Journal Title
Journal ISSN
Volume Title
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Abstract

DFT calculations on a series of oligomers have been used to estimate band gaps, ionization potentials, electron affinities, and bandwidths for polyacetylene, polythiophene, polypyrrole, polythiazole, and a thiophene - thiazole copolymer. Using a slightly modified hybrid functional, we obtain band gaps within 0.1 eV of experimental solid-state values Calculated bond lengths and bond angles for the central ring of sexithiophene differ by less than 0.026 Å and 0.7° from those of the sexithiopnene crystal structure. IPs and EAs are overestimated by up to 0.77 eV compared to experimental bulk values. Extrapolated bandwidths agree reasonably well with bandwidths from band structure calculations.

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Keywords
Approximation theory, Chemical bonds, Copolymers, Crystal structure, Electron energy levels, Energy gap, Ionization, Organic polymers, Polyacetylenes, Probability density function, Band gap, Electron affinities, Ionization potentials, Polypyrrole, Polythiophene, Band structure
Citation
Published Version (Please cite this version)