Enhanced Fill Factor through Chalcogen Side-Chain Manipulation in Small-Molecule Photovoltaics

Thomas J. Aldrich, Matthew J. Leonardi, Alexander S. Dudnik, Nicholas D. Eastham, Boris Harutyunyan, Thomas J. Fauvell, Eric F. Manley, Nanjia Zhou, Melanie R. Butler, Tobias Harschneck, Mark A. Ratner, Lin X. Chen, Michael J. Bedzyk, Robert P.H. Chang, Ferdinand S. Melkonyan*, Antonio Facchetti, Tobin J. Marks

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

20 Scopus citations


The fill factor (FF) of organic photovoltaic (OPV) devices has proven difficult to optimize by synthetic modification of the active layer materials. In this contribution, a series of small-molecule donors (SMDs) incorporating chalcogen atoms of increasing atomic number (Z), namely oxygen, sulfur, and selenium, into the side chains are synthesized and the relationship between the chalcogen Z and the FF of OPV devices is characterized. Larger Z chalcogen atoms are found to consistently enhance FF in bulk-heterojunction OPVs containing PC61BM as the acceptor material. A significant ∼8% FF increase is obtained on moving from O to S to Se across three series of SMDs. The FF enhancement is found to result from the combination of more ordered morphology and decreased charge recombination in blend films for the high-Z-chalcogen SMDs. Because this FF enhancement is found within three series of SMDs, the overall strategy is promising for new SMD materials design.

Original languageEnglish (US)
Pages (from-to)2415-2421
Number of pages7
JournalACS Energy Letters
Issue number10
StatePublished - Oct 13 2017

ASJC Scopus subject areas

  • Chemistry (miscellaneous)
  • Renewable Energy, Sustainability and the Environment
  • Fuel Technology
  • Energy Engineering and Power Technology
  • Materials Chemistry


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