TY - JOUR
T1 - Oxidation of a Molecule by the Biexcitonic State of a CdS Quantum Dot
AU - Lian, Shichen
AU - Christensen, Joseph A.
AU - Kodaimati, Mohamad S.
AU - Rogers, Cameron R.
AU - Wasielewski, Michael R.
AU - Weiss, Emily A.
N1 - Funding Information:
This project is primarily supported by the National Science Foundation under Award CHE-1664184 (QD synthesis, NMR experiments, and optical measurements), and by the Center for Light Energy Activated Redox Processes (LEAP), an Energy Frontier Research Center funded by the U.S. Department of Energy (DOE), Office of Science, Basic Energy Sciences (BES), under Award DE-SC0001059 (synthesis and chemical analysis). C.R.R. thanks the International Institute for Nanotechnology (IIN) at Northwestern University for a fellowship (synthesis). M.S.K. thanks the PPG Foundation for a graduate fellowship (calculations). The authors thank Prof. Ryan Young and Dr. Kedy Edme for helpful discussions.
Publisher Copyright:
© 2019 American Chemical Society.
PY - 2019/3/14
Y1 - 2019/3/14
N2 - This paper describes spectroscopic evidence for the photoinduced transfer of a hole from the biexcitonic state of a CdS quantum dot (QD) to a phenothiazine (PTZ) molecular acceptor, covalently linked to the QD through phenyldithiocarbamate (PTC), with power-dependent yields of 8-21%. Visible and near-infrared transient absorption spectroscopy (TA) data suggest that the mechanisms of hole extraction include direct hole transfer from the QD's valence band to PTZ in 2.4 ± 0.2 ps, or trapping of holes at the QD surface in ∼1 ps, followed by sequential hole transfer to PTZ. Both of these mechanisms potentially out-compete Auger recombination of biexcitonic states, which occurs within these QDs in 20 ± 1 ps. These results suggest that the PTC linkage will be useful for extracting multiple holes from a QD photosensitizer or solo photocatalyst to drive multistep oxidation reactions.
AB - This paper describes spectroscopic evidence for the photoinduced transfer of a hole from the biexcitonic state of a CdS quantum dot (QD) to a phenothiazine (PTZ) molecular acceptor, covalently linked to the QD through phenyldithiocarbamate (PTC), with power-dependent yields of 8-21%. Visible and near-infrared transient absorption spectroscopy (TA) data suggest that the mechanisms of hole extraction include direct hole transfer from the QD's valence band to PTZ in 2.4 ± 0.2 ps, or trapping of holes at the QD surface in ∼1 ps, followed by sequential hole transfer to PTZ. Both of these mechanisms potentially out-compete Auger recombination of biexcitonic states, which occurs within these QDs in 20 ± 1 ps. These results suggest that the PTC linkage will be useful for extracting multiple holes from a QD photosensitizer or solo photocatalyst to drive multistep oxidation reactions.
UR - http://www.scopus.com/inward/record.url?scp=85063062902&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85063062902&partnerID=8YFLogxK
U2 - 10.1021/acs.jpcc.9b00210
DO - 10.1021/acs.jpcc.9b00210
M3 - Article
AN - SCOPUS:85063062902
SN - 1932-7447
VL - 123
SP - 5923
EP - 5930
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
IS - 10
ER -