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


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:
Divisions: College of Engineering & Physical Sciences > School of Infrastructure and Sustainable Engineering > Chemical Engineering & Applied Chemistry
College of Engineering & Physical Sciences > Aston Institute of Materials Research (AIMR)
Additional Information: This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.
Uncontrolled Keywords: General Chemistry,Renewable Energy, Sustainability and the Environment,General Materials Science
Publication ISSN: 2050-7496
Last Modified: 08 Jul 2024 07:27
Date Deposited: 19 Aug 2019 10:09
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Related URLs: http://www.scop ... tnerID=8YFLogxK (Scopus URL)
http://pubs.rsc ... 5B#!divAbstract (Publisher URL)
PURE Output Type: Article
Published Date: 2016-10-28
Published Online Date: 2016-09-15
Accepted Date: 2016-09-14
Submitted Date: 2016-06-29
Authors: Silva, Hugo Santos
Domínguez, Isabel Fraga
Perthué, Anthony
Topham, Paul D. (ORCID Profile 0000-0003-4152-6976)
Bussière, Pierre Olivier
Hiorns, Roger C.
Lombard, Christian
Rivaton, Agnès
Bégué, Didier
Pépin-Donat, Brigitte



Version: Published Version

License: Creative Commons Attribution

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