Chem. J. Chinese Universities ›› 2023, Vol. 44 ›› Issue (7): 20230050.doi: 10.7503/cjcu20230050

• Article • Previous Articles     Next Articles

Non-fullerene Acceptors with Germanium as Bridge Atom and Their Applications in Organic Solar Cells

ZHANG Yi1, SHAN Tong1, WANG Yan1, ZHONG Hongliang1,2()   

  1. 1.School of Chemistry and Chemical Engineering,Shanghai Jiao Tong University,Shanghai 200240,China
    2.Shenzhen Research Institute,Shanghai Jiao Tong University,Shenzhen 518057,China
  • Received:2023-02-07 Online:2023-07-10 Published:2023-05-12
  • Contact: ZHONG Hongliang E-mail:hlzhong@sjtu.edu.cn
  • Supported by:
    the Shenzhen Science and Technology Innovation Commission, China(2021SZVUP075)

Abstract:

Organic photovoltaic materials are composed of conjugated backbone and alkyl sidechain, which bear the functions of photo-sensitivity and solubilization. The bridge atom which is used to connect the backbone and the sidechain is rarely studied, although it plays a key role in determining molecular geometry and optoelectronic property. Herein, this work developed acceptor materials with germanium bridge and investigates the structure-property relationship. Compared with the traditional C—C bond, the longer C—Ge bond affected the planarity of the conjugated backbone as well as the distance between the backbone and the sidechain. Moreover, the fluorinated terminal was introduced into the acceptor GD4F-C8 to tune molecular geometry and packing order by non-covalent bond interaction which was induced by the fluorine atoms. As a result, GD4F-C8 has a broad absorption spectrum and suitable energy levels. More importantly, the compatibility of GD4F-C8 and the polymer donor PM6 is improved to deliver an active layer with favorable morphology. Eventually, organic solar cells based on PM6∶GD4F-C8 achieves a power conversion efficiency of 8.74%, demonstrating the potential of germanium-containing materials in organic solar cells and providing a new insight for acceptor design.

Key words: Organic solar cell, Germanium, Non-fullerene acceptor, Molecular geometry

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