The Influence of Solvent Additive on Polymer Solar Cells Employing Fullerene and Non-Fullerene Acceptors

Xin Song*, Nicola Gasparini, Derya Baran

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

58 Scopus citations

Abstract

Small-molecule-based non-fullerene acceptors (NFAs) are emerging as a new field in organic photovoltaics, due to their structural versatility, the tunability of their energy levels, and their ease of synthesis. High-efficiency polymer donors have been tested with these non-fullerene acceptors in order to further boost the efficiency of organic solar cells. Most of the polymer:fullerene systems are optimized with solvent additives for high efficiency, while little attention has been paid to NFA-based solar cells so far. In this report, the effect of the most common additive, 1,8-diiodooctane (DIO), on PTB7-Th:PC71BM solar cells is investigated and it is compared with non-fullerene acceptor 3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-indanone))-5,5,11,11-tetrakis(4-hexylphenyl)-dithieno[2,3-d:2′,3′-d′]-s-indaceno-[1,2-b:5,6b′]di-thiophene (ITIC) devices. It is interesting that the high boiling solvent additive does have a negative impact on the power conversion efficiency when PTB7-Th is blended with ITIC acceptor. The solar cell devices are studied in terms of their optical, photophysical, and morphological properties and find out that PTB7-Th:ITIC devices with DIO results in coarser domains, reduced absorption strength, and slightly lower mobility, while DIO improves the absorption strength of the PTB7-Th:PC71BM blend film and increase the aggregation of PC71BM in the blend, resulting in higher fill factor and Jsc.

Original languageEnglish (US)
Article number1700358
JournalAdvanced Electronic Materials
Volume4
Issue number10
DOIs
StatePublished - Oct 2018

Bibliographical note

Publisher Copyright:
© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Keywords

  • ITIC
  • non-fullerene acceptor
  • organic solar cell
  • solvent additive
  • trap-assisted recombination

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials

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