Semi-crystalline A 1 -D-A 2 -type copolymers for efficient polymer solar cells

Thanh Luan Nguyen, Hyosung Choi, Seo Jin Ko, Taehyo Kim, Mohammad Afsar Uddin, Sungu Hwang, Jin Young Kim, Han Young Woo

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4 Citations (Scopus)

Abstract

A series of acceptor 1 -donor-acceptor 2 (A 1 -D-A 2)-type copolymers was designed and synthesized using thiophene as an electron-rich unit and benzothiadiazole (BT) and benzotriazole (BTz) as electron-deficient moieties. A weaker acceptor, BTz, was incorporated as a solubilizing moiety with three tetradecyl (or tetradecyloxy) side chains, and a stronger acceptor, BT, was substituted with different numbers of fluorines to modulate the intramolecular charge transfer interaction and the resulting electronic structures. The similar molecular structures of BT and BTz did not disrupt the interchain organization significantly, and the absence of solubilizing alkyl substituents on the electron-rich thiophene did not increase the highest occupied molecular orbital of the resulting polymers. The polymers showed broad absorption in the range of 350-750 nm. Intra- and/or interchain non-covalent coulombic interactions (for example, dipole-dipole interactions via S···O, S···F) ensured a planar backbone and a semi-crystalline morphology in the film. Bulk heterojunction polymer solar cells were fabricated using blends of the polymers and phenyl-C 71 -butyric acid methyl ester (PC 71 BM). For a difluoro-BT containing polymer (BTzDT2FBT), a power conversion efficiency up to 7% was achieved with a short circuit current density of 14.64 mA cm -2, open circuit voltage of 0.75 V and fill factor of 0.64.

Original languageEnglish
Pages (from-to)141-148
Number of pages8
JournalPolymer Journal
Volume49
Issue number1
DOIs
Publication statusPublished - 2017 Jan 1

ASJC Scopus subject areas

  • Polymers and Plastics
  • Materials Chemistry

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  • Cite this

    Nguyen, T. L., Choi, H., Ko, S. J., Kim, T., Uddin, M. A., Hwang, S., Kim, J. Y., & Woo, H. Y. (2017). Semi-crystalline A 1 -D-A 2 -type copolymers for efficient polymer solar cells. Polymer Journal, 49(1), 141-148. https://doi.org/10.1038/pj.2016.88