Ultrafast Two-Electron Transfer in a CdS Quantum Dot-Extended-Viologen Cyclophane Complex

Ryan M. Young, Stephen C. Jensen, Kedy Edme, Yilei Wu, Matthew D. Krzyaniak, Nicolaas A. Vermeulen, Edward J. Dale, J. Fraser Stoddart, Emily A. Weiss, Michael R. Wasielewski, Dick T. Co

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30 Citations (Scopus)


Time-resolved optical spectroscopies reveal multielectron transfer from the biexcitonic state of a CdS quantum dot to an adsorbed tetracationic compound cyclobis(4,4′-(1,4-phenylene) bipyridin-1-ium-1,4-phenylene-bis(methylene)) (ExBox4+) to form both the ExBox3+• and the doubly reduced ExBox2(+•) states from a single laser pulse. Electron transfer in the single-exciton regime occurs in 1 ps. At higher excitation powers the second electron transfer takes ∼5 ps, which leads to a mixture of redox states of the acceptor ligand. The doubly reduced ExBox2(+•) state has a lifetime of ∼10 ns, while CdS+•:ExBox3+• recombines with multiple time constants, the longest of which is ∼300 μs. The long-lived charge separation and ability to accumulate multiple charges on ExBox4+ demonstrate the potential of the CdS:ExBox4+ complex to serve as a platform for two-electron photocatalysis.

Original languageEnglish
Pages (from-to)6163-6170
Number of pages8
JournalJournal of the American Chemical Society
Issue number19
Publication statusPublished - May 18 2016

ASJC Scopus subject areas

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

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