Li, W., Xiao, Z., Cai, J. et al. (14 more authors) (2019) Correlating the electron-donating core structure with morphology and performance of carbon-oxygen-bridged ladder-type non-fullerene acceptor based organic solar cells. Nano Energy, 61. pp. 318-326. ISSN 2211-2855
Abstract
The chemical structure of non-fullerene acceptors (NFAs) affects their light-harvesting capabilities, energy levels and molecular orders, all of which play a crucial role in determining the efficiency of organic solar cells (OSCs). In this work, we have systematically investigated a series of ladder-type NFAs having different carbon-oxygen-bridged electron-donating cores, and revealed the effects of core structures and film casting conditions on molecular ordering and performance of OSCs. We found that NFAs containing the thieno [3,2-b]thiophene centered, 6 or 8 fused rings (i.e. COi6DFIC, COi8DFIC) exhibit narrower optical band gaps than NFAs containing the benzene centered, 5 or 7 fused rings (i.e. COi5DFIC, COi7DFIC). NFAs containing less fused rings in the carbon-oxygen-bridged core (i.e. COi5DFIC and COi6DFIC) exhibit edge-on molecular orientation in the blends with face-on oriented PTB7-Th donor, and result in low device efficiency. Although NFAs containing more fused rings (i.e. COi7DFIC and COi8DFIC) possess a pronounced flat-on lamellar crystalline structure in the pure state, the crystallization can be reduced when blending with PTB7-Th and under hot-substrate casting, while the lamella in COi8DFIC can be effectively suppressed to form face-on H- and J-type aggregates, leading to enhanced efficiency.
Metadata
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Copyright, Publisher and Additional Information: | © 2019 Elsevier. This is an author produced version of a paper subsequently published in Nano Energy. Uploaded in accordance with the publisher's self-archiving policy. Article available under the terms of the CC-BY-NC-ND licence (https://creativecommons.org/licenses/by-nc-nd/4.0/). | ||||||
Keywords: | Organic solar cells; Non-fullerene acceptors; Molecular order; Device efficiency | ||||||
Dates: |
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Institution: | The University of Sheffield | ||||||
Academic Units: | The University of Sheffield > Faculty of Science (Sheffield) > Department of Physics and Astronomy (Sheffield) | ||||||
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Depositing User: | Symplectic Sheffield | ||||||
Date Deposited: | 10 Jun 2019 10:34 | ||||||
Last Modified: | 26 Apr 2020 00:38 | ||||||
Status: | Published | ||||||
Publisher: | Elsevier | ||||||
Refereed: | Yes | ||||||
Identification Number: | https://doi.org/10.1016/j.nanoen.2019.04.053 |