Chemical Research in Chinese Universities ›› 2023, Vol. 39 ›› Issue (2): 213-218.doi: 10.1007/s40242-023-2346-4

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Stable Radical TEMPO Terminated Perylene Bisimide(PBI) Based Small Molecule as Cathode Interlayer for Efficient Organic Solar Cells

ZHANG Ziwei1, XIA Dongdong2, XIE Qian2, ZHAO Chaowei2, FANG Jie2, WU Yonggang1, LI Weiwei3   

  1. 1. College of Chemistry and Environmental Science, Hebei University, Baoding 071002, P. R. China;
    2. Institute of Applied Chemistry, Jiangxi Academy of Sciences, Nanchang 330096, P. R. China;
    3. Beijing Advanced Innovation Center for Soft Matter Science and Engineering and State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, P. R. China
  • Received:2022-12-15 Online:2023-04-01 Published:2023-03-16
  • Contact: LI Weiwei, WU Yonggang, FANG Jie E-mail:liweiwei@iccas.ac.cn;wuyonggang@hbu.edu.cn;fangj17@lzu.edu.cn
  • Supported by:
    This work was supported by the National Natural Science Foundation of China (Nos.92163128, 52073016, 52163018), the Open Project of State Key Laboratory of Organic-Inorganic Composites, China(No.oic-202201006) and the Fund of the Academy of Sciences of Jiangxi Province, China(Nos.2022YJC2017, 2021YSBG22034, 2021YSBG22033).

Abstract: By combining stable radical tetramethylpiperidine nitrogen oxide(TEMPO) as end groups and perylene bisimide(PBI) as the core, a small molecular cathode interlayer(CIL) (PBI-TEMPO) was synthesized. Detailed physical-chemical characterizations indicate that PBI-TEMPO can form smooth film, owns low unoccupied molecular orbital(LUMO) level of –3.67 eV and can reduce the work function of silver electrode. When using PBI-TEMPO as CIL in non-fullerene organic solar cells(OSCs), the PM6:BTP-4Cl based OSCs delivered high power conversion efficiencies(PCEs) up to 17.37%, higher than those using commercial PDINO CIL with PCEs of 16.95%. Further device characterizations indicate that PBI-TEMPO can facilitate more efficient exciton dissociation and reduce charge recombination, resulting in enhanced current density and fill factor. Moreover, PBI-TEMPO displays higher thermal stability than PDINO in solution. When PBI-TEMPO and PDINO solution were heated at 150 ℃ for 2 h and then were used as CIL in solar cells, PBI-TEMPO-based OSCs provided a PCE of 15%, while PDINO-based OSCs only showed a PCE of 10%. These results demonstrate that incorporating TEMPO into conjugated materials is a useful strategy to create new organic semiconductors for application in OSCs.

Key words: Tetramethylpiperidine nitrogen oxide(TEMPO), Perylene bisimide, Cathode interlayer, Organic solar cell, Power conversion efficiency