A comparison of para, meta, and ortho-carborane centred non-fullerene acceptors for organic solar cells

Abstract
We report the first examples of carborane-containing non-fullerene acceptors (NFAs), and their use in organic photovoltaic (OPV) devices. NFAs employing an A–D–A′–D–A type design centred around a central electron withdrawing carborane unit (A′), using either para, meta, or ortho-carborane isomers are reported. We demonstrate that the nature of the isomer has a major impact on device performance, despite minor differences in optoelectronic and morphological properties, with the use of ortho-carborane resulting in the highest device efficiencies. We further show that end-group fluorination is an efficient strategy to modulate energy levels and improve device performance of such NFAs.

Citation
Aniés, F., Furlan, F., Qiao, Z., Pirela, V., Bidwell, M., Rimmele, M., Martín, J., Gasparini, N., & Heeney, M. (2023). A comparison of para, meta, and ortho-carborane centred non-fullerene acceptors for organic solar cells. Journal of Materials Chemistry C. https://doi.org/10.1039/d2tc05018h

Acknowledgements
We thank the Engineering and Physics Science Research Council (EPSRC) (EP/V048686/1 and EP/T028513/1) and the Royal Society and Wolfson Foundation for financial support. F. A. acknowledges the Wilkinson Charitable Foundation for financial support. This work was supported by King Abdullah University of Science and Technology (KAUST) Office of Sponsored Research (OSR) under award OSR-2019-CRG8-4095.

Publisher
Royal Society of Chemistry (RSC)

Journal
Journal of Materials Chemistry C

DOI
10.1039/d2tc05018h

Additional Links
http://xlink.rsc.org/?DOI=D2TC05018H

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