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Journal ArticleDOI

Studies on 3-(2-ethylhexyl)thiophene polymers

01 Apr 2002-Macromolecular Materials and Engineering (Wiley)-Vol. 287, Iss: 4, pp 236-242
Abstract: The regio-regularity and properties of the poly[3-(2-ethylhexyl)thiophene] were studied, and compared with the poly[3′-(2-ethylhexyl)-2,2′,5′,2′′-terthiophene]. The thermal stability of the polymers was improved due to the addition of thiophene rings with (2-ethylhexyl)thiophene. Due to the additional thiophenes at the 2,5 position of ethylhexylthiophene, even though the absorption wavelength was red-shifted, there is no characteristic change in photoemission for the latter polymer. Addition of thiophene rings to the 3-(2-ethylhexyl)thiophene improves the thermal properties without loosing the 3-(2-ethylhexyl)thiophene characteristics.
Topics: Thiophene (69%)
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04 Sep 2008-Macromolecules
Abstract: π-Conjugated block copolymers have been prepared from terminal azide functionalized polystyrenes (PS) and alkyne functionalized poly(3-hexylthiophene)s (P3HT) via a copper(I) catalyzed Huisgen [3 + 2] dipolar cycloaddition reaction. The functionalized α-azido-PS homopolymer was prepared by atom transfer radical polymerization from a specifically designed initiator bearing the azide function, whereas ω-ethynyl-P3HT and α,ω-pentynyl-P3HT were synthesized by a modified Grignard metathesis polymerization using alkynyl Grignard derivatives. The electronic environment of the alkynyl end groups was shown to be decisive in determining triazole ring formation.

131 citations

Journal ArticleDOI
18 Apr 2012-Macromolecules
Abstract: Although recently considerable attention has been paid to the impact of polymer alkyl side chains on conjugated-polymer:fullerene solar cell performance, and especially the Voc and Jsc, a clear and comprehensive picture of the effect of side-chain positioning, length, and branching has yet to evolve. In order to address some of these questions, we designed a simple and modular model system of random copolymers based on rr-P3HT. The influence of increasing amounts of branched 2-ethylhexyl side chains (10, 25, and 50%) in rr-poly(3-hexylthiophene-co-3-(2-ethylhexyl)thiophene) copolymers on properties such as UV–vis absorption, polymer crystallinity, HOMO energy levels, polymer:PC61BM solar cell performance, and especially the Voc was studied and compared to the corresponding homopolymers P3HT and poly(3-(2-ethylhexyl)thiophene) (P3EHT). Polymers with 50% or less 2-ethylhexyl side chains (P3HT90-co-EHT10, P3HT75-co-EHT25, P3HT50-co-EHT50) have the same band gap and similar absorption properties and also reta...

112 citations

Journal ArticleDOI
TL;DR: The synthesis and characterization of a series of poly(3-alkyltellurophene)s are described, which open up a wide range of future studies involving tellurium-based polyheterocycles.
Abstract: The synthesis and characterization of a series of poly(3-alkyltellurophene)s are described. Polymers are prepared by both electrochemical and Kumada catalyst transfer polymerization methods. These polymers have reasonably high molecular weights (Mn = 5.4–11.3 kDa) and can be processed in a manner analogous to that of their lighter atom analogues. All examples exhibit red-shifted optical absorption, as well as solid-state organization, as evidenced by absorption spectroscopy and atomic force microscopy. Overall, the synthesis and characterization of these materials open up a wide range of future studies involving tellurium-based polyheterocycles.

108 citations

Journal ArticleDOI
Abstract: A simplified route to regio-regular poly(3-alkylthiophene)s (P3AT) with predetermined molecular weights and low molecular weight distributions based on the chain-growth GRIM polymerisation of 2,5-dibromo-3-alkylthiophenes is detailed. It is proposed by way of in-depth 13 C-, 1 H- and two-dimensional NMR characterisations that the resulting P3ATs are quasi-100% regio-regular except for one regio-irregular pair at one chain-end. It is probable that chain-end groups exhibit reduced conjugation with the rest of the polymer. A comparison of the preparation of poly(3-hexylthiophene) and poly(3-butylthiophene) (P3BT) is presented. New methods required for the hydrogenation, formylation and bromomethylation of the chain-ends of P3BT, necessary to overcome its poor solubility and low reactivity, are described.

38 citations

Journal ArticleDOI
Abstract: This review focuses on the interrelation between the influences of polymeric structure on the optical properties of polythiophene — a versatile polymer for opto-electronic applications. From the application's point of view, the polymer should either be melt- or solution-processible. Functionalization of polythiophenes really helps for the above. On the other hand, the functionalization at the 3 and/or 4 position of the thiophene ring modifies the band gap of the polymer, which in turn, modifies photo absorption, photo- and electro-emission characteristics of polythiophenes. The present work reviews the influence of the optical properties of polythiophene on the different functional groups present in the thiophene ring.

23 citations

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