Increased Exciton Delocalization of Polymer upon Blending with Fullerene
© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
| Publié dans: | Advanced materials (Deerfield Beach, Fla.). - 1998. - 30(2018), 30 vom: 22. Juli, Seite e1801392 |
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| Auteur principal: | |
| Autres auteurs: | , , , , , , , , , , |
| Format: | Article en ligne |
| Langue: | English |
| Publié: |
2018
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| Accès à la collection: | Advanced materials (Deerfield Beach, Fla.) |
| Sujets: | Journal Article Frenkel exciton charge transfer states electroabsorption exciton delocalization polarizability |
| Résumé: | © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Interfaces between donor and acceptor in a polymer solar cell play a crucial role in exciton dissociation and charge photogeneration. While the importance of charge transfer (CT) excitons for free carrier generation is intensively studied, the effect of blending on the nature of the polymer excitons in relation to the blend nanomorphology remains largely unexplored. In this work, electroabsorption (EA) spectroscopy is used to study the excited-state polarizability of polymer excitons in several polymer:fullerene blend systems, and it is found that excited-state polarizability of polymer excitons in the blends is a strong function of blend nanomorphology. The increase in excited-state polarizability with decreased domain size indicates that intermixing of states at the interface between the donor polymers and fullerene increases the exciton delocalization, resulting in an increase in exciton dissociation efficiency. This conclusion is further supported by transient absorption spectroscopy and time-resolved photoluminescence measurements, along with the results from time-dependent density functional theory calculations. These findings indicate that polymer excited-state polarizability is a key parameter for efficient free carrier generation and should be considered in the design and development of high-performance polymer solar cells |
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| Description: | Date Completed 24.08.2018 Date Revised 30.09.2020 published: Print-Electronic Citation Status PubMed-not-MEDLINE |
| ISSN: | 1521-4095 |
| DOI: | 10.1002/adma.201801392 |