The Impact of Acceptor-Acceptor Homocoupling on the Optoelectronic Properties and Photovoltaic Performance of PDTSQxff Low Bandgap Polymers

G. Pirotte, Jurgen Kesters, Tom Cardeynaels, Pieter Verstappen, Laurence Lutsen, Benoît Champagne, Dirk Vanderzande, Wouter Maes

Research output: Contribution to journalArticle


Push-pull-type conjugated polymers applied in organic electronics do not always contain a perfect alternation of donor and acceptor building blocks. Misscouplings can occur, which have a noticeable effect on the device performance. In this work, the influence of homocoupling on the optoelectronic properties and photovoltaic performance of PDTSQxff polymers is investigated, with a specific focus on the quinoxaline acceptor moieties. A homocoupled biquinoxaline segment is intentionally inserted in specific ratios during the polymerization. These homocoupled units cause a gradually blue-shifted absorption, while the highest occupied molecular orbital energy levels decrease only significantly upon the presence of 75-100% of homocouplings. Density functional theory calculations show that the homocoupled acceptor unit generates a twist in the polymer backbone, which leads to a decreased conjugation length and a reduced aggregation tendency. The virtually defect-free PDTSQxff affords a solar cell efficiency of 5.4%, which only decreases substantially upon incorporating a homocoupling degree over 50%.
Original languageEnglish
Article number1800086
JournalMacromol Rapid Communications
Issue number14
Publication statusPublished - 1 Jul 2018



  • Stille crosscoupling
  • donor-acceptor polymers
  • homocoupling
  • polymer solar cells
  • donor–acceptor polymers

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