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Title: Facet-Specific Electron Transfer in Pseudo-Two-Dimensional Wurtzite Cadmium Selenide Nanocrystals
Ligand-exchange reactions of wurtzite CdSe quantum platelets (QPs) and quantum belts (QBs) with methyl viologen (MV2+) and the derivative ligands MV2+(CH2)nNH2 (n = 2, 4, or 6) are investigated. The QP and QB photoluminescence is quenched after partial ligand exchange. Spectroscopic and compositional data establish that this initial ligand substitution occurs on the thin QP and QB edges. The MV2+(CH2)nNH2 ligands are shown to be more-efficient photoluminescence quenchers than the parent MV2+ ion. The ligands on the thin, nonpolar, long-edge facets quench the photoluminescence via the trapping of excitons. Transient absorption experiments indicate the excitons dissociate, and electron transfer to the MV2+(CH2)nNH2 ligands only occurs at the polar, short-edge facets of the wurtzite CdSe QPs and QBs. Electron transfer to the MV2+(CH2)nNH2 ligands occurs within 100 fs when exciting at the band edge and on longer time scales, due to intraband relaxation, when exciting at higher energies.  more » « less
Award ID(s):
1905751
NSF-PAR ID:
10484536
Author(s) / Creator(s):
; ; ;
Publisher / Repository:
American Chemical Society
Date Published:
Journal Name:
The Journal of Physical Chemistry C
Volume:
127
Issue:
37
ISSN:
1932-7447
Page Range / eLocation ID:
18506 to 18517
Subject(s) / Keyword(s):
Cadmium selenide, Charge transfer, Ligands, Ligation, Quenching
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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