Chem. J. Chinese Universities ›› 2023, Vol. 44 ›› Issue (9): 20230190.doi: 10.7503/cjcu20230190

• Article • Previous Articles     Next Articles

Fused-benzotriazole Based p-Type Polymers: Fine-tuning on Absorption Band-width and Bandgap via Backbone Thiophene and Selenophene Strategies

TIAN Mei, ZHANG Zhiyang, ZHAN Chuanlang()   

  1. Key Laboratory of Advanced Materials Chemistry and Devices of the Department of Education of Inner Mongolia Autonomous Region,College of Chemistry and Environmental Science,Inner Mongolia Normal University,Hohhot 010022,China
  • Received:2023-04-17 Online:2023-09-10 Published:2023-06-14
  • Contact: ZHAN Chuanlang E-mail:clzhan@imnu.edu.cn
  • Supported by:
    the Program of the Department of Science and Technology of Inner Mongolia, China(2020GG0192);the Natural Science Foundation of Inner Mongolia, China(2022ZD04);the Program of the Inner Mongolia Normal University, China(112/1004031962)

Abstract:

Four fused-benzotriazole based p-type polymers(BDT-TT, BDT-Se, BDD-TT, and BDD-Se) were designed and synthesized, and the fine-tuning on absorption band-widths and bandgaps via the backbone selenophene and thiophene strategies were reported. First, we introduced dithienothiophen[3,2-b]pyrrolobenzotriazole to co-polymerize with BDT-2F and synthesized BDT-TT. Then, we used selenophene to replace the thienothiophene units on the dithienothiophen[3,2-b]pyrrolobenzotriazole and synthesized BDT-Se. Compared to BDT-TT, BDT-Se showed a reduced bandgap from 2.0 eV to 1.89 eV. After that, we used BDD to replace BDT-2F and synthesized BDD-TT by co-polymerizing with dithienothiophen[3,2-b]pyrrolobenzotriazole. In comparison to BDT-TT, BDD-TT showed extended absorption band-width with the full-width-at-the-half-maximum(FWHM) increased from 138 nm to 229 nm and reduced bandgap from 2.0 eV to 1.71 eV. At last, we combined BDD and diselenophen[3,2-b]pyrrolobenzotriazole and synthesized BDD-Se, which achieved extended absorption and further reduced bandgap(1.61 eV). Using PC71BM as the electron acceptor material, the organic solar cells fabricated by the four polymers gave the efficiencies of 1%—2%.

Key words: Benzotriazole, Fused-ring, Polymer, Organic solar cell, Bandgap

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