Synthesis and characterization of a wide bandgap polymer based on a weak donor-weak acceptor structure for dual applications in organic solar cells and organic photodetectors

Eun Young Choi, Seung Hun Eom, Chang Eun Song, So Youn Nam, Jaemin Lee, Han Young Woo, In Hwan Jung, Sung Cheol Yoon, Changjin Lee

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

We synthesized a novel wide bandgap polymer, PDTFBT, forming a weak donor (WD)-weak acceptor (WA) structure for use in organic photodetectors (OPDs) and organic solar cells (OSCs). The fluorination in the D unit and the alkoxy substitution in the A unit induced WD and WA properties, respectively. The WD-WA structure of PDTFBT effectively broadened the bandgap compared to typical D-A structures, and the S-F and S-O dipole-dipole interactions induces a highly planar backbone structure with excellent π-π stacking in the vertical direction. In OPDs, conformationally less disordered PDTFBT polymer retained the constant responsivity and significantly improved the detectivity of PDTFBT:PC71BM devices even with a thick active layer of 470 nm, contrary to the variation in the responsivity of P3HT:PC61BM devices depending on the thickness. In OSCs, the deep HOMO energy level (−5.57 eV) of PDTFBT led to high Voc of 0.92 V in PDTFBT:PC71BM devices, which was 0.3 eV higher than that of P3HT:PC61BM devices (0.62 V), resulting in 1.8-fold enhanced power conversion efficiency. We demonstrated that the WD-WA structure with S-F and S-O interactions is highly promising strategy to make wide bandgap polymers for organic photodetectors and for the bottom cell of tandem architecture.

Original languageEnglish
Pages (from-to)173-182
Number of pages10
JournalOrganic Electronics: physics, materials, applications
Volume46
DOIs
Publication statusPublished - 2017 Jul 1

Keywords

  • Alkoxy benzothiadiazole
  • Fluorination
  • Organic photodetectors
  • Organic solar cells
  • Wide bandgap polymer

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Chemistry(all)
  • Condensed Matter Physics
  • Materials Chemistry
  • Electrical and Electronic Engineering

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