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Molecular vibrations reduce the maximum achievable photovoltage in organic solar cells

The low-energy edge of optical absorption spectra is critical for the performance of solar cells, but is not well understood in the case of organic solar cells (OSCs). We study the microscopic origin of exciton bands in molecular blends and investigate their role in OSCs. We simulate the temperature...

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Autores principales: Panhans, Michel, Hutsch, Sebastian, Benduhn, Johannes, Schellhammer, Karl Sebastian, Nikolis, Vasileios C., Vangerven, Tim, Vandewal, Koen, Ortmann, Frank
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group UK 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7083957/
https://www.ncbi.nlm.nih.gov/pubmed/32198376
http://dx.doi.org/10.1038/s41467-020-15215-x
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author Panhans, Michel
Hutsch, Sebastian
Benduhn, Johannes
Schellhammer, Karl Sebastian
Nikolis, Vasileios C.
Vangerven, Tim
Vandewal, Koen
Ortmann, Frank
author_facet Panhans, Michel
Hutsch, Sebastian
Benduhn, Johannes
Schellhammer, Karl Sebastian
Nikolis, Vasileios C.
Vangerven, Tim
Vandewal, Koen
Ortmann, Frank
author_sort Panhans, Michel
collection PubMed
description The low-energy edge of optical absorption spectra is critical for the performance of solar cells, but is not well understood in the case of organic solar cells (OSCs). We study the microscopic origin of exciton bands in molecular blends and investigate their role in OSCs. We simulate the temperature dependence of the excitonic density of states and low-energy absorption features, including low-frequency molecular vibrations and multi-exciton hybridisation. For model donor-acceptor blends featuring charge-transfer excitons, our simulations agree very well with temperature-dependent experimental absorption spectra. We unveil that the quantum effect of zero-point vibrations, mediated by electron-phonon interaction, causes a substantial exciton bandwidth and reduces the open-circuit voltage, which is predicted from electronic and vibronic molecular parameters. This effect is surprisingly strong at room temperature and can substantially limit the OSC’s efficiency. Strategies to reduce these vibration-induced voltage losses are discussed for a larger set of systems and different heterojunction geometries.
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spelling pubmed-70839572020-03-23 Molecular vibrations reduce the maximum achievable photovoltage in organic solar cells Panhans, Michel Hutsch, Sebastian Benduhn, Johannes Schellhammer, Karl Sebastian Nikolis, Vasileios C. Vangerven, Tim Vandewal, Koen Ortmann, Frank Nat Commun Article The low-energy edge of optical absorption spectra is critical for the performance of solar cells, but is not well understood in the case of organic solar cells (OSCs). We study the microscopic origin of exciton bands in molecular blends and investigate their role in OSCs. We simulate the temperature dependence of the excitonic density of states and low-energy absorption features, including low-frequency molecular vibrations and multi-exciton hybridisation. For model donor-acceptor blends featuring charge-transfer excitons, our simulations agree very well with temperature-dependent experimental absorption spectra. We unveil that the quantum effect of zero-point vibrations, mediated by electron-phonon interaction, causes a substantial exciton bandwidth and reduces the open-circuit voltage, which is predicted from electronic and vibronic molecular parameters. This effect is surprisingly strong at room temperature and can substantially limit the OSC’s efficiency. Strategies to reduce these vibration-induced voltage losses are discussed for a larger set of systems and different heterojunction geometries. Nature Publishing Group UK 2020-03-20 /pmc/articles/PMC7083957/ /pubmed/32198376 http://dx.doi.org/10.1038/s41467-020-15215-x Text en © The Author(s) 2020 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.
spellingShingle Article
Panhans, Michel
Hutsch, Sebastian
Benduhn, Johannes
Schellhammer, Karl Sebastian
Nikolis, Vasileios C.
Vangerven, Tim
Vandewal, Koen
Ortmann, Frank
Molecular vibrations reduce the maximum achievable photovoltage in organic solar cells
title Molecular vibrations reduce the maximum achievable photovoltage in organic solar cells
title_full Molecular vibrations reduce the maximum achievable photovoltage in organic solar cells
title_fullStr Molecular vibrations reduce the maximum achievable photovoltage in organic solar cells
title_full_unstemmed Molecular vibrations reduce the maximum achievable photovoltage in organic solar cells
title_short Molecular vibrations reduce the maximum achievable photovoltage in organic solar cells
title_sort molecular vibrations reduce the maximum achievable photovoltage in organic solar cells
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7083957/
https://www.ncbi.nlm.nih.gov/pubmed/32198376
http://dx.doi.org/10.1038/s41467-020-15215-x
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