Efficiencies of organic solar cells have practically doubled since the development of non-fullerene acceptors (NFAs). However, generic chemical design rules for donor-NFA combinations are still needed. Such rules are proposed by analyzing inhomogeneous electrostatic fields at the donor–acceptor interface. It is shown that an acceptor–donor–acceptor molecular architecture, and molecular alignment parallel to the interface, results in energy level bending that destabilizes the charge transfer state, thus promoting its dissociation into free charges. By analyzing a series of PCE10:NFA solar cells, with NFAs including Y6, IEICO, and ITIC, as well as their halogenated derivatives, it is suggested that the molecular quadrupole moment of ≈75 Debye Å balances the losses in the open circuit voltage and gains in charge generation efficiency.
|Original language||English (US)|
|Journal||Advanced Energy Materials|
|State||Published - Oct 8 2021|
Bibliographical noteKAUST Repository Item: Exported on 2021-10-12
Acknowledged KAUST grant number(s): OSR-2018-CARF/CCF-3079, OSR-CRG2018-3746
Acknowledgements: A.M. has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 844655 (SMOLAC). This publication is based on work supported by the KAUST Office of Sponsored Research (OSR) under award nos. OSR-2018-CARF/CCF-3079 and OSR-CRG2018-3746. D.A. also acknowledges the KAUST PSE Division for hosting his sabbatical in the framework of the Division's Visiting Faculty program. D.A. acknowledges funding by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) for financial support through the collaborative research centers TRR 146, SPP 2196, and grant number 460766640. K.-H.L. acknowledges the financial support from the Swiss NSF Early Postdoc Mobility fellowship (grant no. P2ELP2_195156). The authors thank Kostas Daoulas, Leanne Paterson, and Naoimi Kinaret for fruitful discussions and proof-reading of the manuscript.
Open access funding enabled and organized by Projekt DEAL.
ASJC Scopus subject areas
- Renewable Energy, Sustainability and the Environment
- Materials Science(all)