Single-Junction Organic Photovoltaic Cells with Approaching 18% Efficiency

Yong Cui; Huifeng Yao; Jianqi Zhang; Kaihu Xian; Tao Zhang; Ling Hong; Yuming Wang; Ye Xu; Kangqiao Ma; Cunbin An; Chang He; Zhixiang Wei; Feng Gao; Jianhui Hou

doi:10.1002/adma.201908205

Single-Junction Organic Photovoltaic Cells with Approaching 18% Efficiency

Adv Mater. 2020 May;32(19):e1908205. doi: 10.1002/adma.201908205. Epub 2020 Mar 29.

Authors

Yong Cui^{1

2}, Huifeng Yao¹, Jianqi Zhang³, Kaihu Xian^{1

2}, Tao Zhang¹, Ling Hong^{1

2}, Yuming Wang^{1

4}, Ye Xu^{1

2}, Kangqiao Ma¹, Cunbin An¹, Chang He¹, Zhixiang Wei^{2

3}, Feng Gao⁴, Jianhui Hou^{1

2}

Affiliations

¹ State Key Laboratory of Polymer Physics and Chemistry, Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.
² University of Chinese Academy of Sciences, Beijing, 100049, China.
³ CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, China.
⁴ Department of Physics, Chemistry and Biology, Linköping University, Linköping, Sweden.

PMID: 32227399
DOI: 10.1002/adma.201908205

Abstract

Optimizing the molecular structures of organic photovoltaic (OPV) materials is one of the most effective methods to boost power conversion efficiencies (PCEs). For an excellent molecular system with a certain conjugated skeleton, fine tuning the alky chains is of considerable significance to fully explore its photovoltaic potential. In this work, the optimization of alkyl chains is performed on a chlorinated nonfullerene acceptor (NFA) named BTP-4Cl-BO (a Y6 derivative) and very impressive photovoltaic parameters in OPV cells are obtained. To get more ordered intermolecular packing, the n-undecyl is shortened at the edge of BTP-eC11 to n-nonyl and n-heptyl. As a result, the NFAs of BTP-eC9 and BTP-eC7 are synthesized. The BTP-eC7 shows relatively poor solubility and thus limits its application in device fabrication. Fortunately, the BTP-eC9 possesses good solubility and, at the same time, enhanced electron transport property than BTP-eC11. Significantly, due to the simultaneously enhanced short-circuit current density and fill factor, the BTP-eC9-based single-junction OPV cells record a maximum PCE of 17.8% and get a certified value of 17.3%. These results demonstrate that minimizing the alkyl chains to get suitable solubility and enhanced intermolecular packing has a great potential in further improving its photovoltaic performance.

Keywords: molecular modification; nonfullerene acceptors; organic photovoltaic cells; power conversion efficiency.

Abstract

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