Homocoupling defects in porphyrinoid small molecules and their effect on organic solar cell performance

Mathias Kelchtermans, Jasper Deckers, Jeroen Brebels, Jurgen Kesters, Pieter Verstappen, Raghavendran Thiruvallur Eachambadi, Zhen Liu, Niko Van den Brande, Jean Manca, Laurence Lutsen, Dirk Vanderzande, Wouter Maes

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3 Citations (Scopus)


Porphyrinoid small molecules can be used as electron donor or acceptor components in bulk heterojunction organic solar cells, which has resulted in steadily improving power conversion efficiencies. However, the effect of material purity is often neglected. In this work, a series of D1-A-π-D2-π-A-D1 conjugated chromophores based on the A 2 B 2 -meso-ethynylporphyrin core is synthesized. Different electron-donating (D1) end groups are chosen to investigate their influence on the material properties and optoelectronic characteristics. The porphyrin small molecules are tested as electron donor materials in bulk heterojunction organic solar cells in combination with PC 71 BM, affording an efficiency up to 4.6% under standard illumination. Furthermore, it is shown that (Glaser type) homocoupled side products are generated during the final Sonogashira cross-coupling reactions, which can be very challenging to remove. Their presence reduces solar cell performance by affecting the open-circuit voltage and fill factor.

Original languageEnglish
Pages (from-to)48-55
Number of pages8
JournalOrganic Electronics
Publication statusPublished - Jun 2019


  • Conjugated small molecules
  • Glaser
  • Homocoupling
  • Material purity
  • Organic photovoltaics
  • Porphyrins

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