Oxidation of a Molecule by the Biexcitonic State of a CdS Quantum Dot

Shichen Lian, Joseph A. Christensen, Mohamad S. Kodaimati, Cameron R. Rogers, Michael R Wasielewski, Emily A Weiss

Research output: Contribution to journalArticle

Abstract

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.

Original languageEnglish
Pages (from-to)5923-5930
Number of pages8
JournalJournal of Physical Chemistry C
Volume123
Issue number10
DOIs
Publication statusPublished - Mar 14 2019

Fingerprint

Semiconductor quantum dots
quantum dots
phenothiazines
Oxidation
oxidation
Molecules
molecules
Photosensitizing Agents
Photosensitizers
Photocatalysts
Valence bands
Absorption spectroscopy
Infrared radiation
linkages
absorption spectroscopy
trapping
valence
phenothiazine

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Energy(all)
  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films

Cite this

Oxidation of a Molecule by the Biexcitonic State of a CdS Quantum Dot. / Lian, Shichen; Christensen, Joseph A.; Kodaimati, Mohamad S.; Rogers, Cameron R.; Wasielewski, Michael R; Weiss, Emily A.

In: Journal of Physical Chemistry C, Vol. 123, No. 10, 14.03.2019, p. 5923-5930.

Research output: Contribution to journalArticle

Lian, Shichen ; Christensen, Joseph A. ; Kodaimati, Mohamad S. ; Rogers, Cameron R. ; Wasielewski, Michael R ; Weiss, Emily A. / Oxidation of a Molecule by the Biexcitonic State of a CdS Quantum Dot. In: Journal of Physical Chemistry C. 2019 ; Vol. 123, No. 10. pp. 5923-5930.
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