Chemical Design Rules for Non-Fullerene Acceptors in Organic Solar Cells

by Anastasia Markina, Kun-Han Lin, Wenlan Liu, Carl Poelking, Yuliar Firdaus, Diego Rosas Villalva, Jafar I.Khan, Sri H. K. Paleti, George T. Harrison, Julien Gorenflot, Weimin Zhang, Stefaan De Wolf, Iain McCulloch, Thomas D. Anthopoulos, Derya Baran, Frédéric Laquai, Denis Andrienko
Research Article Year: 2021 DOI: https://doi.org/10.1002/aenm.202102363

Bibliography

Markina, A., Lin, K., Liu, W., Poelking, C., Firdaus, Y., Rosas Villalva, D., Khan, I. J., Paleti, S.H.K., Harrison, G.T., Gorenflot, J., Zhang, W., De Wolf, S., McCulloch, I., Anthopoulos, T.D., Baran, D., Laquai, F., Andrienko, D.  

Abstract

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.

Keywords

design rules donor-acceptor interface Non-fullerene acceptors organic solar cells