Issue 2, 2021

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


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.

Graphical abstract: A pyrrolopyridazinedione-based copolymer for fullerene-free organic solar cells

Supplementary files

Article information

Article type
12 Sep 2020
04 Dec 2020
First published
24 Dec 2020
This article is Open Access
Creative Commons BY license

New J. Chem., 2021,45, 1001-1009

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

A. Knall, S. Rabensteiner, S. F. Hoefler, M. Reinfelds, M. Hobisch, H. M. A. Ehmann, N. Pastukhova, E. Pavlica, G. Bratina, I. Hanzu, S. Wen, R. Yang, G. Trimmel and T. Rath, New J. Chem., 2021, 45, 1001 DOI: 10.1039/D0NJ04573J

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