TY - JOUR
T1 - Ultrafast Two-Electron Transfer in a CdS Quantum Dot-Extended-Viologen Cyclophane Complex
AU - Young, Ryan M.
AU - Jensen, Stephen C.
AU - Edme, Kedy
AU - Wu, Yilei
AU - Krzyaniak, Matthew D.
AU - Vermeulen, Nicolaas A.
AU - Dale, Edward J.
AU - Stoddart, J. Fraser
AU - Weiss, Emily A
AU - Wasielewski, Michael R
AU - Co, Dick T
PY - 2016/5/18
Y1 - 2016/5/18
N2 - 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.
AB - 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.
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U2 - 10.1021/jacs.5b13386
DO - 10.1021/jacs.5b13386
M3 - Article
AN - SCOPUS:84971220423
VL - 138
SP - 6163
EP - 6170
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
SN - 0002-7863
IS - 19
ER -