Anion Localization on Termini of a Non‐Fullerene Acceptor Aids Charge Transport
Abstract Non‐fullerene acceptors have revolutionised organic photovoltaics. However, greater fundamental understanding is needed of the crucial relationships between molecular structure and photophysical mechanisms. Herein, a combination of spectroscopic, morphology, and device characterization techniques are used to explore these relationships for a high‐performing non‐fullerene acceptor, anti‐PDFC. It focuses on transient absorption spectroscopy across multiple timescales and ultrafast time‐resolved vibrational spectroscopy to acquire the “holy grail” of simultaneous structural and dynamic information for anti‐PDFC and its blend with the well‐known conjugated polymer PM6. Most significantly, it is observed that the singlet exciton of anti‐PDFC is localised on the perylene diimide central core of the molecule, but the radical anion is primarily localised on the fluorinated indene malonitrile terminal units (which are common to many state‐of‐the‐art non‐fullerene acceptors, including the Y6 family). This electron transfer from the central core to the termini of an adjacent molecule is facilitated by a close interaction between the termini and the central core, as evidenced by single crystal diffraction data and excited state calculations. Finally, the very efficient charge extraction measured for PM6:anti‐PDFC photovoltaic devices may be correlated with this anion localization, enabling effective charge transport channels and thus enhancing device performance.
Authors
- Junjun Guo (ORCID: https://orcid.org/0000-0002-4458-2597)
- Tracey M. Clarke (ORCID: https://orcid.org/0000-0003-4943-0645)
- Hongliang Zhong (ORCID: https://orcid.org/0000-0003-2499-8007)
- Ricardo J. Fernández‐Terán (ORCID: https://orcid.org/0000-0002-4665-3520)
- Martin V. Appleby (ORCID: https://orcid.org/0000-0002-4936-4003)
- James D. Shipp (ORCID: https://orcid.org/0000-0002-0452-8895)
- Kui Ding (ORCID: https://orcid.org/0000-0002-3196-1539)
- Dimitri Chekulaev
- Igor V. Sazanovich (ORCID: https://orcid.org/0000-0002-8000-7645)
- Nicola Gasparini (ORCID: https://orcid.org/0000-0002-3226-8234)
- Zhuoran Qiao (ORCID: https://orcid.org/0000-0002-6144-4081)
- Rachel Crespo‐Otero (ORCID: https://orcid.org/0000-0002-8725-5350)
- Tong Shan (ORCID: https://orcid.org/0000-0001-5695-2543)
- Julia A. Weinstein
Institutions
- University of Geneva (CH)
- Rutherford Appleton Laboratory (GB)
- University of Pittsburgh (US)
- Shanghai Jiao Tong University (CN)
- Paul Scherrer Institute (CH)
- Research Complex at Harwell (GB)
- Chevron (United States) (US)
- Shenzhen Technology University (CN)
- University College London (GB)
- Imperial College London (GB)
- University of Sheffield (GB)
- Tsinghua University (CN)
Publication Details
- Journal
- Advanced Energy Materials
- Published
- 2025-01-10
- DOI
- https://doi.org/10.1002/aenm.202404926
- Citations
- 2
- Primary Topic
- Organic Electronics and Photovoltaics
- Type
- article
- Field-Weighted Citation Impact
- 1.46
Funders
- National Science Foundation
- Grantham Centre for Sustainable Futures
- Leverhulme Trust
- University of Cambridge
- European Commission
- Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung
- National Natural Science Foundation of China
- King Abdullah University of Science and Technology
- Shanghai Jiao Tong University
- Université de Genève
- Engineering and Physical Sciences Research Council
- Science and Technology Facilities Council