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The number of electrons needed to be accumulated to raise
the Fermi level is not easily measurable. Using spectroelectro-
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likely to be very sensitive to particle size, solvent polarity, and
dielectric perturbations due to the junction with the QD.
Assuming that the double-layer capacitance of the Ag island
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The primary aim of this initial study was to demonstrate that
electron equilibration occurs in QD-metal colloid systems
during photolysis. It was shown that simple spectroscopic
methods enable one to monitor electron transfer processes at
metal-QD junctions relatively easily. It was also demonstrated
that during extensive photolysis, electron capture by metal
islands of Ag, Au, and Cu becomes inhibited as the redox
potential is cathodically shifted and approaches the ZnO
conduction band level. At this point, electrons reside for long
periods on both the QD and metal island. Photocatalysis is
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Acknowledgment. The authors thank the ARC for support
of this research. A.W. is the recipient of a Melbourne Research
Scholarship. P.M. thanks the Humboldt Foundation for support
of part of this project.
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References and Notes
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