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

Authors :
Zhang, Guichuan
Chen, Xian-Kai
Xiao, Jingyang
Chow, Philip C. Y.
Ren, Minrun
Kupgan, Grit
Jiao, Xuechen
Chan, Christopher C. S.
Du, Xiaoyan
Xia, Ruoxi
Chen, Ziming
Yuan, Jun
Zhang, Yunqiang
Zhang, Shoufeng
Liu, Yidan
Zou, Yingping
Yan, He
Wong, Kam Sing
Coropceanu, Veaceslav
Li, Ning
Source :
Nature Communications; 8/7/2020, Vol. 11 Issue 1, p1-10, 10p
Publication Year :
2020

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. Y6, as a non-fullerene acceptor for organic solar cells, has attracted intensive attention because of the low voltage loss and high charge generation efficiency. Here, Zhang et al. find that the delocalization of exciton and electron wavefunction due to strong π-π packing of Y6 is the key for the high performance. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
20411723
Volume :
11
Issue :
1
Database :
Complementary Index
Journal :
Nature Communications
Publication Type :
Academic Journal
Accession number :
145077928
Full Text :
https://doi.org/10.1038/s41467-020-17867-1