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

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

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Author(s)

  • Guichuan Zhang
  • Xian-Kai Chen
  • Jingyang Xiao
  • Philip C. Y. Chow
  • Minrun Ren
  • Grit Kupgan
  • Xuechen Jiao
  • Christopher C. S. Chan
  • Xiaoyan Du
  • Ruoxi Xia
  • Ziming Chen
  • Jun Yuan
  • Yunqiang Zhang
  • Shoufeng Zhang
  • Yidan Liu
  • Yingping Zou
  • He Yan
  • Kam Sing Wong
  • Veaceslav Coropceanu
  • Ning Li
  • Christoph J. Brabec
  • Jean-Luc Bredas
  • Yong Cao

Detail(s)

Original languageEnglish
Article number3943
Journal / PublicationNature Communications
Volume11
Online published7 Aug 2020
Publication statusPublished - 2020
Externally publishedYes

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.

Citation Format(s)

Delocalization of exciton and electron wavefunction in non-fullerene acceptor molecules enables efficient organic solar cells. / 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; Brabec, Christoph J.; Bredas, Jean-Luc; Yip, Hin-Lap; Cao, Yong.

In: Nature Communications, Vol. 11, 3943, 2020.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review