Delocalization of exciton and electron wavefunction in non-fullerene acceptor molecules enables efficient organic solar cells

Zhang G, Chen XK, Xiao J, Chow PC, Ren M, Kupgan G, Jiao X, Chan CC, Du X, Xia R, Chen Z, Yuan J, Zhang Y, Zhang S, Liu Y, Zou Y, Yan H, Wong KS, Coropceanu V, Li N, Brabec C, Bredas JL, Yip HL, Cao Y (2020)

Publication Type: Journal article

Publication year: 2020

Journal

Nature Communications Nature Publishing Group: Nature Communications

Book Volume: 11

Article Number: 3943

Journal Issue: 1

DOI: 10.1038/s41467-020-17867-1

Abstract

A major challenge for organic solar cell (OSC) research is how to minimize the tradeoff between voltage loss and charge generation. In early 2019, we reported a non-fullerene acceptor (named Y6) that can simultaneously achieve high external quantum efficiency and low voltage loss for OSC. Here, we use a combination of experimental and theoretical modeling to reveal the structure-property-performance relationships of this state-of-the-art OSC system. We find that the distinctive π–π molecular packing of Y6 not only exists in molecular single crystals but also in thin films. Importantly, such molecular packing leads to (i) the formation of delocalized and emissive excitons that enable small non-radiative voltage loss, and (ii) delocalization of electron wavefunctions at donor/acceptor interfaces that significantly reduces the Coulomb attraction between interfacial electron-hole pairs. These properties are critical in enabling highly efficient charge generation in OSC systems with negligible donor-acceptor energy offset.

Authors with CRIS profile

Xiaoyan Du Institute Materials for Electronics and Energy Technology (i-MEET) Ning Li Institute Materials for Electronics and Energy Technology (i-MEET) Christoph Brabec Institute Materials for Electronics and Energy Technology (i-MEET)

Involved external institutions

South China University of Technology (SCUT) / 华南理工大学 CN China (CN) Georgia Institute of Technology US United States (USA) (US) University of Hong Kong (HKU) / 香港大學 HK Hong Kong (HK) University of Science and Technology of China (USTC) CN China (CN) Hong Kong University of Science and Technology (HKUST) / 香港科技大學 CN China (CN) Central South University CN China (CN)

How to cite

APA:

Zhang, G., Chen, X.K., Xiao, J., Chow, P.C., Ren, M., Kupgan, G.,... Cao, Y. (2020). Delocalization of exciton and electron wavefunction in non-fullerene acceptor molecules enables efficient organic solar cells. Nature Communications, 11(1). https://doi.org/10.1038/s41467-020-17867-1

MLA:

Zhang, Guichuan, et al. "Delocalization of exciton and electron wavefunction in non-fullerene acceptor molecules enables efficient organic solar cells." Nature Communications 11.1 (2020).

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