A pyrrolopyridazinedione-based copolymer for fullerene-free organic solar cells

Astrid Caroline Knall*, Samuel Rabensteiner, Sebastian Franz Hoefler, Matiss Reinfelds, Mathias Hobisch, Heike M.A. Ehmann, Nadiia Pastukhova, Egon Pavlica, Gvido Bratina, Ilie Hanzu, Shuguang Wen, Renqiang Yang, Gregor Trimmel, Thomas Rath

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

The recent success of non-fullerene acceptors in organic photovoltaics also entails a change in the requirements to the polymer donor in terms of optical and morphological properties leading to a demand for novel conjugated polymers. Herein, we report on the synthesis of a 1,4-bis-(thiophene-2-yl)-pyrrolopyridazinedione based copolymer with 2-ethylhexyl substituents on the pyrrolopyridazinedione moiety. A 2D conjugated benzodithiophene (BDT) was chosen as comonomer. The resulting copolymer T-EHPPD-T-EHBDT showed a molecular weight of 10.2 kDa, an optical band gap of 1.79 eV, a hole mobility of 1.8 × 10-4 cm2 V-1 s-1 and a preferred face-on orientation with regard to the substrate. The comparably wide band gap as well as the determined energy levels (HOMO: -5.47 eV, LUMO: -3.68 eV) match well with the narrow band gap non-fullerene acceptor ITIC-F, which was used as the acceptor phase in the bulk heterojunction absorber layers in the investigated solar cells. The solar cells, prepared in inverted architecture, revealed power conversion efficiencies up to 7.4% using a donor:acceptor ratio of 1 : 1 in the absorber layer. This journal is

Original languageEnglish
Pages (from-to)1001-1009
Number of pages9
JournalNew Journal of Chemistry
Volume45
Issue number2
DOIs
Publication statusPublished - 14 Jan 2021

ASJC Scopus subject areas

  • Catalysis
  • General Chemistry
  • Materials Chemistry

Fields of Expertise

  • Advanced Materials Science

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