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Volume 8, Issue 2 (Suppl) Chem Sci J 2017
ISSN: 2150-3494 CSJ, an open access journal Euro Chemistry 2017
May 11-13, 2017
May 11-13, 2017 Barcelona, Spain
4th European Chemistry Congress
Pervin Unal Civcir, Chem Sci J 2017, 8:2(Suppl)
ATheoretical Calculations of Band Gaps of conducting polymers with electron donor–acceptor unit
Pervin Unal Civcir
Ankara University, Turkey
The interaction between alternating donors and acceptors results in a diminished band gap. With determining the proper donor
(D) and acceptor (A) groups, it is possible to decrease the band gap (<1.8 eV) as much as possible or to adjust HOMO (highest
occupied molecular orbital)-LUMO (lowest unoccupied molecular orbital) levels. Therefore, in this study the theoretical methods
were used for the modelling of the donor–acceptor type conjugated polymers. Quantum chemical calculations were performed
using density functional theory (DFT) to investigate the HOMO–LUMO energy gap of benzothiadiazole based donor–acceptor
type conjugated polymers: poly{4,7-bis(3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepin-6-yl)benzo[c][1,2,5]thiadiazole} (P1), poly{4,7-
bis(3,3-dimethyl-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepin-6-yl)benzo[c][1,2,5]thiadiazole} (P2), poly{4,7-bis(3,4-dihydro-2H-
thieno[3,4-b][1,4]dioxepin-6-yl)-5,6-diphenylbenzo [c][1,2,5]thiadiazole} (P3) and poly{4,7-bis(3,3-dimethyl-3,4-dihydro-
2H-thieno[3,4-b][1,4]dioxepin-6-yl)-5,6-diphenyl-benzo[c][1,2,5] thiadiazole} (P4). DFT is one of the most successful quantum
chemistry tools for the description of ground-state properties of metals, semiconductors and insulators. Compared to other quantum
chemistry methods, the DFT approach gives low computational cost and accurate results. The geometries of the monomers and
oligomers were optimized using semi-empirical PM6 method in the gas phase. The band gaps of the polymers were performed by the
B3LYP level of theory (Becke three-parameter hybrid correlation functional combined with Lee–Yang–Parr correlation functional)
with 6-31G(d) basis set. Band gaps of the studied polymers were obtained by extrapolating oligomers gaps to infinite chain lengths.
The results indicate that calculated band gaps are in good agreement with the experimental values in the literature. The theoretical
methods used in this study are promising for the modelling of similar donor–acceptor type novel conjugated polymers.
Biography
Civcir completed her PhD at the University of East Anglia, UK in 1992 and became a professor in Ankara University in 2009. She is a lecturer in Ankara University,
Faculty of Science, Chemistry Department. She works in the field of Organic and Computational Chemistry and has published more than15 papers in reputed
journal. She has written a Chemistry book in Turkish. She was involved in translating the five Chemistry books from English to Turkish.