Synthesis, characterization, Raman, and surface enhanced Raman studies of semiconductor quantum dots
Item
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Title
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Synthesis, characterization, Raman, and surface enhanced Raman studies of semiconductor quantum dots
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Identifier
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d_2009_2013:5b9565af7704:11236
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identifier
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11484
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Creator
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Pan, Yi,
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Contributor
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John R. Lombardi
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Date
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2012
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Language
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English
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Publisher
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City University of New York.
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Subject
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Inorganic chemistry | Nanoscience | Nanotechnology | 1-tetradecene | lead chloride | oleylamine | non-injection | one-pot synthesis | nucleation at low temperature | Selenium quantum dots | Semiconductor quantum dots | Surface enhanced Raman Spectroscopy and Raman
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Abstract
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The major contributions and discoveries of the dissertation include: (1) Homogeneous nucleation processes for the formation of nanocrystals can occur at low temperature and do not need to proceed at high temperature to overcome a high energy barrier. Monodisperse PbS quantum dots (QDs) obtained with nucleation and growth at 45°C support this finding. (2) Monodisperse single elemental Se QDs can be produced by simple solution crystallization from TDE (1-tetradecene) or ODE (1-octadecene). (3) TDE is a better non-coordinating solvent compare to ODE. STDE (S dissolved in TDE) and SeTDE (Se dissolved in TDE) are stable reagents with long storage time. They can be used as universal precursors for S-containing and Se-containing QDs. (4) QDs synthesis can be carried out at low temperature and relatively short reaction time using the simple, non-injection, one-pot synthetic method. (5) The one-pot method can be extended for the synthesis of QDs and graphene oxide nanocomposites and metal and graphene oxide nanocomposites. (6) PbCl2-OLA (oleylamine) is a universal system for the synthesis of Pb-chaclogenides QDs. (7) Surface enhanced Raman spectroscopy (SERS) is used to probe both size and wave length dependent quantum confinement effects (QCEs) of PbS QDs. (8) Raman spectroscopy is a powerful tool to elucidate crystal structure of Se nanoclusters with size of 1--2 nm.;Semiconductor QDs have attracted considerable attention due to their potential for energy-efficient materials in optoelectronic and solar cell applications. When the radius of a QD is decreased to that of the exciton Bohr radius, the valence and conduction bands are known to split into narrower bands due to QCEs. QCEs are both size and wave length dependent. We have developed, synthesized and characterized a series of Pb-chaclogenide QDs, which all the sizes of the QDs are monodisperse and smaller than their respective exciton Bohr radius, to study the QCEs of these QDs.;SERS is used as a crucial tool to investigate these QCEs. The QCEs are due to any of the following three resonances or a combination among them: interband resonance, molecular state resonance, and charge-transfer resonance.
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Type
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dissertation
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Source
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2009_2013.csv
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degree
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Ph.D.
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Program
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Chemistry
