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Influence of Backbone Fluorination in Regioregular Poly(3-alkyl-4-fluoro)thiophenes.
- Source :
-
Journal of the American Chemical Society [J Am Chem Soc] 2015 Jun 03; Vol. 137 (21), pp. 6866-79. Date of Electronic Publication: 2015 May 21. - Publication Year :
- 2015
-
Abstract
- We report two strategies toward the synthesis of 3-alkyl-4-fluorothiophenes containing straight (hexyl and octyl) and branched (2-ethylhexyl) alkyl groups. We demonstrate that treatment of the dibrominated monomer with 1 equiv of alkyl Grignard reagent leads to the formation of a single regioisomer as a result of the pronounced directing effect of the fluorine group. Polymerization of the resulting species affords highly regioregular poly(3-alkyl-4-fluoro)thiophenes. Comparison of their properties to those of the analogous non-fluorinated polymers shows that backbone fluorination leads to an increase in the polymer ionization potential without a significant change in optical band gap. Fluorination also results in an enhanced tendency to aggregate in solution, which is ascribed to a more co-planar backbone on the basis of Raman and DFT calculations. Average charge carrier mobilities in field-effect transistors are found to increase by up to a factor of 5 for the fluorinated polymers.
Details
- Language :
- English
- ISSN :
- 1520-5126
- Volume :
- 137
- Issue :
- 21
- Database :
- MEDLINE
- Journal :
- Journal of the American Chemical Society
- Publication Type :
- Academic Journal
- Accession number :
- 25994804
- Full Text :
- https://doi.org/10.1021/jacs.5b02785