Excitons dominate the emission from PM6
- Non-fullerene acceptors (NFAs) are far more emissive than their fullerene-based counterparts. Here, we study the spectral properties of photocurrent generation and recombination of the blend of the donor polymer PM6 with the NFA Y6. We find that the radiative recombination of free charges is almost entirely due to the re-occupation and decay of Y6 singlet excitons, but that this pathway contributes less than 1% to the total recombination. As such, the open-circuit voltage of the PM6:Y6 blend is determined by the energetics and kinetics of the charge-transfer (CT) state. Moreover, we find that no information on the energetics of the CT state manifold can be gained from the low-energy tail of the photovoltaic external quantum efficiency spectrum, which is dominated by the excitation spectrum of the Y6 exciton. We, finally, estimate the charge-separated state to lie only 120 meV below the Y6 singlet exciton energy, meaning that this blend indeed represents a high-efficiency system with a low energetic offset.
Author details: | Lorena Perdigón-ToroORCiDGND, Le Quang Phuong, Stefan ZeiskeORCiD, Koen VandewalORCiDGND, Ardalan ArminORCiD, Safa ShoaeeORCiDGND, Dieter NeherORCiDGND |
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DOI: | https://doi.org/10.1021/acsenergylett.0c02572 |
ISSN: | 2380-8195 |
Title of parent work (English): | ACS energy letters / American Chemical Society |
Subtitle (English): | Y6 solar cells, but this does not help the open-circuit voltage of the device |
Publisher: | American Chemical Society |
Place of publishing: | Washington |
Publication type: | Article |
Language: | English |
Date of first publication: | 2021/01/15 |
Publication year: | 2021 |
Release date: | 2024/04/15 |
Volume: | 6 |
Issue: | 2 |
Number of pages: | 8 |
First page: | 557 |
Last Page: | 564 |
Funding institution: | Alexander von Humboldt FoundationAlexander von Humboldt Foundation; Ser Cymru II Program through the Welsh Government; European Regional Development FundEuropean Commission; Swansea University strategic initiative in Sustainable Advanced Materials; UKRI EPSRC Doctoral Training Partnership studentshipUK Research & Innovation (UKRI)Engineering & Physical Sciences Research Council (EPSRC); European Research Council (ERC)European Research Council (ERC)European Commission [864625]; Welsh European Funding Office |
Organizational units: | Mathematisch-Naturwissenschaftliche Fakultät / Institut für Physik und Astronomie |
DDC classification: | 5 Naturwissenschaften und Mathematik / 54 Chemie / 540 Chemie und zugeordnete Wissenschaften |
Peer review: | Referiert |