Influence of molecular designs on polaronic and vibrational transitions in a conjugated push-pull copolymer

Cobet, Christoph and Gasiorowski, Jacek and Menon, Reghu and Hingerl, Kurt and Schlager, Stefanie and White, Matthew S and Neugebauer, Helmut and Sariciftci, Serdar N and Stadler, Philipp (2016) Influence of molecular designs on polaronic and vibrational transitions in a conjugated push-pull copolymer. In: SCIENTIFIC REPORTS, 6 .

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Abstract

Electron-phonon interactions of free charge-carriers in doped pi-conjugated polymers are conceptually described by 1-dimensional (1D) delocalization. Thereby, polaronic transitions fit the 1D-Froehlich model in quasi-confined chains. However, recent developments in conjugated polymers have diversified the backbones to become elaborate heterocylcic macromolecules. Their complexity makes it difficult to investigate the electron-phonon coupling. In this work we resolve the electron-phonon interactions in the ground and doped state in a complex push-pull polymer. We focus on the polaronic transitions using in-situ spectroscopy to work out the differences between single-unit and push-pull systems to obtain the desired structural- electronic correlations in the doped state. We apply the classic 1D-Froehlich model to generate optical model fits. Interestingly, we find the 1D-approach in push-pull polarons in agreement to the model, pointing at the strong 1D-character and plain electronic structure of the push-pull structure. In contrast, polarons in the single-unit polymer emerge to a multi-dimensional problem difficult to resolve due to their anisotropy. Thus, we report an enhancement of the 1D-character by the push-pull concept in the doped state - an important view in light of the main purpose of push-pull polymers for photovoltaic devices.

Item Type:	Journal Article
Publication:	SCIENTIFIC REPORTS
Additional Information:	Copy right for this article belongs to the NATURE PUBLISHING GROUP, MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	03 Dec 2016 06:21
Last Modified:	03 Dec 2016 06:21
URI:	http://eprints.iisc.ac.in/id/eprint/55267

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