Ultrafast Two-Electron Transfer in a CdS Quantum Dot–Extended-Viologen Cyclophane Complex
- Northwestern Univ., Evanston, IL (United States); Energy Frontier Research Centers (EFRC) (United States). Argonne-Northwestern Solar Energy Research Center (ANSER)
- Northwestern Univ., Evanston, IL (United States)
Time-resolved optical spectroscopies revealmulti-electron transfer from the biexcitonic state of a CdS quantum dot toan adsorbed tetracationic compoundcyclobis(4,4'-(1,4-phenylene)bipyridin-1-ium-1,4-phenylene-bis(methylene))(ExBox4+)to formboth the ExBox3+∙and the doubly reduced ExBox2(+∙)statesfrom a single laser pulse. Electron transfer in the single-exciton regime occurs in 1 ps.At higher excitation powers the second electron transfertakes~5ps, which leadsto a mixture of redox states of the acceptor ligand.The doubly reducedExBox2(+∙)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 photocataly-sis.
- Research Organization:
- Energy Frontier Research Centers (EFRC) (United States). Argonne-Northwestern Solar Energy Research Center (ANSER)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES); Camille and Henry Dreyfus Postdoctoral Program in Environmental Chemistry; National Science Foundation (NSF); Ryan Fellowship; International Institute for Nanotechnology (IIN)
- Grant/Contract Number:
- SC0001059
- OSTI ID:
- 1387722
- Journal Information:
- Journal of the American Chemical Society, Journal Name: Journal of the American Chemical Society Journal Issue: 19 Vol. 138; ISSN 0002-7863
- Publisher:
- American Chemical Society (ACS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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