Ultrafast Two-Electron Transfer in a CdS Quantum Dot-Extended-Viologen Cyclophane Complex.
J Am Chem Soc
; 138(19): 6163-70, 2016 05 18.
Article
in En
| MEDLINE
| ID: mdl-27111529
ABSTRACT
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)) (ExBox(4+)) to form both the ExBox(3+â¢) and the doubly reduced ExBox(2(+â¢)) 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 â¼5 ps, which leads to a mixture of redox states of the acceptor ligand. The doubly reduced ExBox(2(+â¢)) state has a lifetime of â¼10 ns, while CdS(+â¢)ExBox(3+â¢) recombines with multiple time constants, the longest of which is â¼300 µs. The long-lived charge separation and ability to accumulate multiple charges on ExBox(4+) demonstrate the potential of the CdSExBox(4+) complex to serve as a platform for two-electron photocatalysis.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Language:
En
Journal:
J Am Chem Soc
Year:
2016
Document type:
Article
Affiliation country:
United States