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  • Perspective
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Decoding the halogenation cost-performance paradox in organic solar cells

Nature Reviews Materials volume 10, pages 617–631 (2025)Cite this article

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Abstract

The power conversion efficiencies of organic solar cells have now surpassed 20%, marking a considerable advance in performance. This progress raises an important question: which molecular or macromolecular modifications contribute most effectively to efficiency gains? Among these, halogenation — specifically fluorination and chlorination — has been a key driver of performance improvements, making it a particularly promising avenue for materials exploration. In this Perspective, we provide a comparative discussion of a broad range of non-halogenated and halogenated building blocks, acceptors and donors, evaluating the impact of halogenation on efficiency and scalability. We also examine critical challenges, including organic solar cell durability, large-scale manufacturability and the realistic costs associated with halogenation, positioning it as a central factor in performance optimization.

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Fig. 1: Key aspects of OSC performance and operation.
Fig. 2: Selected non-halogenated and halogenated building blocks.
Fig. 3: Plots of NSS, RY and SFt values for selected organic solar cell building blocks.
Fig. 4: Plots showing SFt,Donor, reported PCE and PCE/SFt,Donor for selected donor materials and the corresponding donor–acceptor pairs.
Fig. 5: Plots showing SFt,Acceptor, reported PCE and PCE/SFt,Acceptor for selected acceptor materials.

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Change history

  • 29 May 2025

    In the version of the article initially published, in the Acknowledgements section, the US Office of Naval Research contract no. N00014-20-1-2110 (Georgia Institute of Technology) was incorrect and has now been amended to N00014-24-1-2110 in the HTML and PDF versions of the article.

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Acknowledgements

The authors gratefully acknowledge the support of US Office of Naval Research under contract nos N00014-24-1-2110 (Georgia Institute of Technology) and N00014-24-1-2109 (Northwestern University), the Qatar National Research Foundation under grant NPRP12S-0304-190227/02-484761 and the Northwestern University Materials Research Science and Engineering Center Award under NSF grant DMR-DMR-2308691.

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  1. Department of Chemistry and the Trienens Institute for Energy and Sustainability, Northwestern University, Evanston, IL, USA

    Guoping Li, Antonio Facchetti & Tobin J. Marks

  2. Lam Research Corporation, Fremont, CA, USA

    Guoping Li

  3. College of Science and Engineering, Hamad Bin Khalifa University, Doha, Qatar

    Mohammed Al-Hashimi

  4. Georgia Institute of Technology, School of Materials Science and Engineering, Atlanta, GA, USA

    Antonio Facchetti

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  1. Guoping Li
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G.L. assembled and researched data for the paper. G.L., M.A.-H., A.F. and T.J.M. drafted and revised the paper. All authors contributed substantially to discussion of the content and reviewed and/or edited the paper before submission.

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Li, G., Al-Hashimi, M., Facchetti, A. et al. Decoding the halogenation cost-performance paradox in organic solar cells. Nat Rev Mater 10, 617–631 (2025). https://doi.org/10.1038/s41578-025-00804-3

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  • DOI: https://doi.org/10.1038/s41578-025-00804-3

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