Yuning Li, G. Vamvounis, S. Holdcroft
Aug 1, 2002
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Influential Citations
135
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Quality indicators
Journal
Macromolecules
Abstract
Postfunctionalization of poly(3-hexylthiophene) (P3HT) enables the systematic study of electronic and steric effects of various functional groups on the optical and photophysical properties of 3,4-disubstituted poly(thiophene)s. In solution, these 3,4-disubstituted poly(thiophene)s exhibit a lower fluorescence yield (Φfl) than P3HT. In the solid state, bromo, chloro, and formyl groups increase Φfl, whereas nitro groups completely quench fluorescence. Phenyl, p-tolyl, 2- and 4-methoxyphenyl, 2-thienyl, biphenyl, and 1-naphthyl substituents increase the solid-state fluorescence of P3HT by a factor of 2−3 as a result of steric interactions that force the aromatic substituents perpendicular to the main chain. An extensive enhancement in the solid-state Φfl, 12 times greater than that of P3HT, is observed for polymers containing ortho-alkylphenyl or 2-(3-alkyl)thienyl groups, because of additional steric interactions between methyl or α-methylene hydrogens on the phenyl or thienyl substituents and main-chain t...