Gradual chlorination at different positions of D-π-A copolymers based on benzodithiophene and isoindigo for organic solar cells

Jialing Zhou; Bao Zhang; Yanfang Geng; Qing Guo; Qiang Guo; Erjun Zhou

Materials Reports: Energy (Nov 2021)

Gradual chlorination at different positions of D-π-A copolymers based on benzodithiophene and isoindigo for organic solar cells

Jialing Zhou,
Bao Zhang,
Yanfang Geng,
Qing Guo,
Qiang Guo,
Erjun Zhou

Affiliations

Jialing Zhou: CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, PR China; Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, PR China
Bao Zhang: Henan Institute of Advanced Technology, Zhengzhou University, Zhengzhou 450001, PR China
Yanfang Geng: CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, PR China; Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, PR China
Qing Guo: Henan Institute of Advanced Technology, Zhengzhou University, Zhengzhou 450001, PR China; Corresponding author.
Qiang Guo: Henan Institute of Advanced Technology, Zhengzhou University, Zhengzhou 450001, PR China
Erjun Zhou: CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, PR China; Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, PR China; Corresponding author. CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, PR China.

Journal volume & issue: Vol. 1, no. 4
p. 100065

Abstract

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Isoindigo (IID) has been widely used as strong acceptor unit (A) to construct narrow bandgap polymers in organic field effect transistors (OFETs) and organic solar cells (OSCs). Combing with IID, we chose benzodithiophene (BDT) as the donor unit (D) and thieno [3,2-b]thiophene (TT) as the π bridge to construct a new type of D-π-A polymer PE70. Based on PE70, we adopt the chlorination strategy to fine-tune photoelectric characteristics and film morphology, and then developed PE74 and PE75. By blending with non-fullerene acceptor (NFA) Y6, device based on PE74 with chloride substitution on the BDT unit showed increasing photovoltaic performance. In addition, further chlorine substitution on the IID (PE75) would greatly reduce the non-radiative voltage loss (ΔV3), and the distorted molecular conformation also took responsible for the excessive recombination. As results, PE74:Y6-based device achieves a power conversion efficiency (PCE) of 11.06% with open-circuit voltage (VOC) of 0.76 V, which are higher than those of PE70:Y6 (PCE of 10.40% and VOC of 0.72 V) and PE75: Y6-based device (PCE of 6.24% and VOC of 0.84 V). This work demonstrates the regularity of the photovoltaic performance caused by chlorination strategy in polymer in the non-fullerene OSC devices, which provide important insights into high-performance photovoltaic materials.

Published in Materials Reports: Energy

ISSN: 2666-9358 (Online)
Publisher: KeAi Communications Co. Ltd.
Country of publisher: China
LCC subjects: Technology: Electrical engineering. Electronics. Nuclear engineering: Materials of engineering and construction. Mechanics of materials
Website: https://www.keaipublishing.com/en/journals/materials-reports-energy/

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