π-Extended Naphthalene Diimide Derivatives for n-Type Semiconducting Polymers

Jianhua Chen, Jianhua Chen, Xinming Zhuang, Xinming Zhuang, Wei Huang, Mengyao Su, Liang Wen Feng, Steven M. Swick, Gang Wang, Yao Chen, Junsheng Yu, Xugang Guo, Tobin Jay Marks*, Antonio Facchetti, Antonio Facchetti

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

The electron-transporting properties of n-type polymers strongly depend on the chemical and electronic structure of the electron-deficient building blocks. Here, we design and develop a novel electron-deficient unit, a thienopyridine-fused naphthalene amide (TPNA), via π-conjugative extension at the diagonal position of the widely investigated naphthalene diimide (NDI) moiety to address the severe π-backbone twisting of typical NDI-based polymers. The TPNA-based homopolymer (Homo-TPNA), donor-acceptor copolymer (TPNA-T, T = thienyl), and all-acceptor copolymer (TPNA-BTz, BTz = benzothiadiazole) were synthesized and characterized. Compared to the NDI unit, TPNA promotes greater π-conjugation, increased electron delocalization, and a nearly planar backbone conformation due to the reduced steric demands of the TPNA-aryl connecting points. 2D GIWAXS indicates that all of the TPNA-based polymers are significantly crystalline and exhibit well-ordered microstructures with distinctive lamellar diffractions (h00) in the out-of-plane direction and close π-πstacking distances of 3.5-3.6 Å. Benefiting from the homopolymer and all-acceptor molecular design strategy, the Homo-TPNA and TPNA-BTz polymers exhibit lower frontier MO energy levels than TPNA-T, which promote electron injection while blocking hole accumulation. Thin-film transistors (TFTs) based on the TPNA polymers exhibit n-channel performance with an optimal electron mobility of 0.19 cm2 V-1 s-1 achieved for TPNA-BTz. These results demonstrate that TPNA is an effective building block for constructing n-type polymers with good backbone planarity and promising electron-transport properties.

Original languageEnglish (US)
Pages (from-to)5317-5326
Number of pages10
JournalChemistry of Materials
Volume32
Issue number12
DOIs
StatePublished - Jun 23 2020

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Chemistry

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