Designing intrinsically photostable low band gap polymers:a smart tool combining EPR spectroscopy and DFT calculations

Silva, Hugo Santos, Domínguez, Isabel Fraga, Perthué, Anthony, Topham, Paul D., Bussière, Pierre Olivier, Hiorns, Roger C., Lombard, Christian, Rivaton, Agnès, Bégué, Didier and Pépin-Donat, Brigitte (2016). Designing intrinsically photostable low band gap polymers:a smart tool combining EPR spectroscopy and DFT calculations. Journal of Materials Chemistry A, 4 (40), pp. 15647-15654.

Abstract

A rapid and efficient method to identify the weak points of the complex chemical structure of low band gap (LBG) polymers, designed for efficient solar cells, when submitted to light exposure is reported. This tool combines Electron Paramagnetic Resonance (EPR) using the 'spin trapping method' coupled with density functional theory modelling (DFT). First, the nature of the short life-time radicals formed during the early-stages of photo-degradation processes are determined by a spin-trapping technique. Two kinds of short life-time radical (R and R′O) are formed after 'short-duration' illumination in an inert atmosphere and in ambient air, respectively. Second, simulation allows the identification of the chemical structures of these radicals revealing the most probable photochemical process, namely homolytical scission between the Si atom of the conjugated skeleton and its pendent side-chains. Finally, DFT calculations confirm the homolytical cleavage observed by EPR, as well as the presence of a group that is highly susceptible to photooxidative attack. Therefore, the synergetic coupling of a spin trapping method with DFT calculations is shown to be a rapid and efficient method for providing unprecedented information on photochemical mechanisms. This approach will allow the design of LBG polymers without the need to trial the material within actual solar cell devices, an often long and costly screening procedure.

Publication DOI: https://doi.org/10.1039/c6ta05455b
Divisions: Engineering & Applied Sciences > Chemical engineering & applied chemistry
Engineering & Applied Sciences > Polymer and advanced materials research group
Additional Information: This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.
Uncontrolled Keywords: Chemistry(all),Renewable Energy, Sustainability and the Environment,Materials Science(all)
Full Text Link: http://pubs.rsc ... 5B#!divAbstract
Related URLs: http://www.scop ... tnerID=8YFLogxK (Scopus URL)
Published Date: 2016-10-28
Authors: Silva, Hugo Santos
Domínguez, Isabel Fraga
Perthué, Anthony
Topham, Paul D. ( 0000-0003-4152-6976)
Bussière, Pierre Olivier
Hiorns, Roger C.
Lombard, Christian
Rivaton, Agnès
Bégué, Didier
Pépin-Donat, Brigitte

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