Chem. J. Chinese Universities ›› 2023, Vol. 44 ›› Issue (7): 20230169.doi: 10.7503/cjcu20230169

• Article • Previous Articles     Next Articles

End-capped Polymer Donors for Highly-efficient Organic Solar Cells

ZHANG Youhui1,2, YANG Na2, DUAN Na2, CHENG Yujun2, YOU Shiyong2, WU Feiyan2(), CHEN Lie2()   

  1. 1.School of Pharmacy,Jiangxi University of Chinese Medicine,Nanchang 330004,China
    2.Institute of Polymers and Energy Chemistry(IPEC),College of Chemistry and Chemical Engineering,Nanchang University,Nanchang 330031,China
  • Received:2023-04-01 Online:2023-07-10 Published:2023-05-05
  • Contact: CHEN Lie E-mail:feiywu@ncu.edu.cn;chenlie@ncu.edu.cn
  • Supported by:
    the National Natural Science Foundation of China(51973087);the Thousand Talents Plan of Jiangxi Province, China(jxsq2019201004);the National Natural Science Foundation of Jiangxi Province, China(2021BAB204052)

Abstract:

End-capping engineering is a very simple and convenient strategy for polymer modification, whereas its application in high performance non-fullerene organic solar cells is still limited. In this paper, three novel fully end-capped donors PM6-T-EH, PM6-2T-EH and PM6-3T-EH were prepared by capped with 2-(2-ethylhexyl)-thiophene(T-EH), 5-(2-ethylhexyl)-2,2′-bithiophene(2T-EH), and 5-(2-ethylhexyl)-2,2′∶5′,2′′-terthiophene(3T-EH), respectively. Compared with pristine polymer donors PM6(15.40%), end-capped polymers PM6-T-EH, PM6-2T-EH, PM6-3T-EH blended with Y6 achieved the power conversion efficiencies(PCE) of 16.66%, 15.54% and 13.50%, respectively. It is shown that the alkyl monothiophene end-capped polymer can reduce the carrier traps, optimize the morphology and improve the charge transport in the active layer, thus enhance the overall PCE. The gradually decreased device performance along with the increase of thiophene units in end-capping groups, is mainly attributed to the deteriorated morphology of active layer, resulting from the bulky conjugated chains of the end- capping groups. Further optimizing the active layer, the device based on PM6-T-EH∶BTP-eC9 achieved a highe efficiency of 18.02%.

Key words: Organic solar cell, Polymer donor, End-capping strategy, Photovoltaic conversion efficiency

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