Regulating the Aggregation of Unfused Non-Fullerene Acceptors via Molecular Engineering towards Efficient Polymer Solar Cells

Yuxiang Li, Huiting Fu, Ziang Wu, Xin Wu, Mei Wang, Hongmei Qin, Francis Lin, Han Young Woo, Alex K.Y. Jen

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

Tuning molecular aggregation via structure design to manipulate the film morphology still remains as a challenge for polymer solar cells based on unfused non-fullerene acceptors (UF-NFAs). Herein, a strategy was developed to modulate the aggregation patterns of UF-NFAs by systematically varying the π-bridge (D) unit and central core (A’) unit in A−D-A’−D−A framework (A and D refer to electron-withdrawing and electron-donating moieties, respectively). Specifically, the quantified contents of H- or J-aggregation and crystallite disorder of three UF-NFAs (BDIC2F, BCIC2F, and TCIC2F) were analyzed via UV/Vis spectrometry and grazing incidence X-ray scattering. The results showed that the H-aggregate-dominated BCIC2F with less crystallite disorder exhibited a more favorable blend morphology with polymer donor PBDB-T (poly[(2,6-(4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b']dithiophene)-co-(1,3-di(5-thiophene-2-yl)-5,7-bis(2-ethylhexyl)benzo[1,2-c:4,5-c']dithiophene-4,8-dione)]) relative the other two UF-NFAs, resulting in improved exciton dissociation and charge tranport. Consequently, photovoltaic devices based on BCIC2F delivered a promising power conversion efficiency of 12.4 % with an exceptionally high short-circuit current density of 22.1 mA cm−2.

Original languageEnglish
Pages (from-to)3579-3589
Number of pages11
JournalChemSusChem
Volume14
Issue number17
DOIs
Publication statusPublished - 2021 Sep 6

Keywords

  • aggregation
  • morphology
  • organic semiconductors
  • photovoltaics
  • solar cells

ASJC Scopus subject areas

  • Environmental Chemistry
  • Chemical Engineering(all)
  • Materials Science(all)
  • Energy(all)

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