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

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

37 Scopus citations


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 (US)
Pages (from-to)6163-6170
Number of pages8
JournalJournal of the American Chemical Society
Issue number19
StatePublished - May 18 2016

ASJC Scopus subject areas

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


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