Systematic investigation of benzodithiophene- and diketopyrrolopyrrole- based low-bandgap polymers designed for single junction and tandem polymer solar cells

Letian Dou, Jing Gao, Eric Richard, Jingbi You, Chun Chao Chen, Kitty C. Cha, Youjun He, Gang Li, Yang Yang

Research output: Journal article publicationJournal articleAcademic researchpeer-review

513 Citations (Scopus)


The tandem solar cell architecture is an effective way to harvest a broader part of the solar spectrum and make better use of the photonic energy than the single junction cell. Here, we present the design, synthesis, and characterization of a series of new low bandgap polymers specifically for tandem polymer solar cells. These polymers have a backbone based on the benzodithiophene (BDT) and diketopyrrolopyrrole (DPP) units. Alkylthienyl and alkylphenyl moieties were incorporated onto the BDT unit to form BDTT and BDTP units, respectively; a furan moiety was incorporated onto the DPP unit in place of thiophene to form the FDPP unit. Low bandgap polymers (bandgap = 1.4-1.5 eV) were prepared using BDTT, BDTP, FDPP, and DPP units via Stille-coupling polymerization. These structural modifications lead to polymers with different optical, electrochemical, and electronic properties. Single junction solar cells were fabricated, and the polymer:PC71BM active layer morphology was optimized by adding 1,8-diiodooctane (DIO) as an additive. In the single-layer photovoltaic device, they showed power conversion efficiencies (PCEs) of 3-6%. When the polymers were applied in tandem solar cells, PCEs over 8% were reached, demonstrating their great potential for high efficiency tandem polymer solar cells.
Original languageEnglish
Pages (from-to)10071-10079
Number of pages9
JournalJournal of the American Chemical Society
Issue number24
Publication statusPublished - 20 Jun 2012
Externally publishedYes

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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