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Control of aggregate formation in poly(3-hexylthiophene) by solvent, molecular weight, and synthetic method

Title data

Scharsich, Christina ; Lohwasser, Ruth H. ; Sommer, Michael ; Asawapirom, Udom ; Scherf, Ullrich ; Thelakkat, Mukundan ; Neher, Dieter ; Köhler, Anna:
Control of aggregate formation in poly(3-hexylthiophene) by solvent, molecular weight, and synthetic method.
In: Journal of Polymer Science Part B: Polymer Physics. Vol. 50 (2012) Issue 6 . - pp. 442-453.
ISSN 1099-0488
DOI: https://doi.org/10.1002/polb.23022

Official URL: Volltext

Project information

Project financing: Deutsche Forschungsgemeinschaft

Abstract in another language

Aggregate formation in poly(3-hexylthiophene) depends on molecular weight, solvent, and synthetic method. The interplay of these parameters thus largely controls device performance. In order to obtain a quantitative understanding on how these factors control the resulting electronic properties of P3HT, we measured absorption in solution and in thin films as well as the resulting field effect mobility in transistors. By a detailed analysis of the absorption spectra, we deduce the fraction of aggregates formed, the excitonic coupling within the aggregates, and the conjugation length within the aggregates, all as a function of solvent quality for molecular weights from 5 to 19 kDa. From this, we infer in which structure the aggregated chains pack. Although the 5 kDa samples form straight chains, the 11 and 19 kDa chains are kinked or folded, with conjugation lengths that increase as the solvent quality reduces. There is a maximum fraction of aggregated chains (about 55 +/- 5%) that can be obtained, even for poor solvent quality. We show that inducing aggregation in solution leads to control of aggregate properties in thin films. As expected, the field-effect mobility correlates with the propensity to aggregation. Correspondingly, we find that a well-defined synthetic approach, tailored to give a narrow molecular weight distribution, is needed to obtain high field effect mobilities of up to 0.01 cm2/Vs for low molecular weight samples (=11 kDa), while the influence of synthetic method is negligible for samples of higher molecular weight, if low molecular weight fractions are removed by extraction.

Further data

Item Type: Article in a journal
Refereed: Yes
Keywords: conformational analysis; conjugated polymers; crystallization; films; interaction parameter; molecular weight distribution/molar mass distribution; nucleation; photophysics; structure; UV–vis spectroscopy
Institutions of the University: Faculties
Faculties > Faculty of Mathematics, Physics und Computer Science > Department of Physics > Chair Experimental Physics II - Optoelectronics of Soft Matter > Chair Experimental Physics II - Optoelectronics of Soft Matter - Univ.-Prof. Dr. Anna Köhler
Faculties > Faculty of Biology, Chemistry and Earth Sciences
Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry
Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry > Chair Macromolecular Chemistry I
Profile Fields
Profile Fields > Advanced Fields
Profile Fields > Advanced Fields > Polymer and Colloid Science
Profile Fields > Emerging Fields
Profile Fields > Emerging Fields > Energy Research and Energy Technology
Graduate Schools
Graduate Schools > Bayreuth Graduate School of Mathematical and Natural Sciences (BayNAT)
Graduate Schools > Bayreuth Graduate School of Mathematical and Natural Sciences (BayNAT) > Photophysics of Synthetic and Biological Multichromophoric Systems
Faculties > Faculty of Mathematics, Physics und Computer Science
Faculties > Faculty of Mathematics, Physics und Computer Science > Department of Physics
Faculties > Faculty of Mathematics, Physics und Computer Science > Department of Physics > Chair Experimental Physics II - Optoelectronics of Soft Matter
Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry > Professor Applied Functional Polymers > Professor Applied Functional Polymers - Univ.-Prof. Dr. Mukundan Thelakkat
Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry > Professor Applied Functional Polymers
Result of work at the UBT: Yes
DDC Subjects: 500 Science > 530 Physics
500 Science > 540 Chemistry
Date Deposited: 13 Apr 2016 06:50
Last Modified: 13 Jul 2022 08:59
URI: https://eref.uni-bayreuth.de/id/eprint/1196