Dissertation/Thesis Abstract

Colloidal Nanocrystals with Near-infrared Optical Properties: Synthesis, Characterization, and Applications
by Panthani, Matthew George, Ph.D., The University of Texas at Austin, 2011, 217; 3572875
Abstract (Summary)

Colloidal nanocrystals with optical properties in the near-infrared (NIR) are of interest for many applications such as photovoltaic (PV) energy conversion, bioimaging, and therapeutics. For PVs and other electronic devices, challenges in using colloidal nanomaterials often deal with the surfaces. Because of the high surface-to-volume ratio of small nanocrystals, surfaces and interfaces play an enhanced role in the properties of nanocrystal films and devices.

Organic ligand-capped CuInSe2 (CIS) and Cu(InXGa 1-X)Se2 (CIGS) nanocrystals were synthesized and used as the absorber layer in prototype solar cells. By fabricating devices from spray-coated CuInSe nanocrystals under ambient conditions, solar-to-electric power conversion efficiencies as high as 3.1% were achieved. Many treatments of the nanocrystal films were explored. Although some treatments increased the conductivity of the nanocrystal films, the best devices were from untreated CIS films. By modifying the reaction chemistry, quantum-confined CuInSe XS2-X (CISS) nanocrystals were produced. The potential of the CISS nanocrystals for targeted bioimaging was demonstrated via oral delivery to mice and imaging of nanocrystal fluorescence.

The size-dependent photoluminescence of Si nanocrystals was measured. Si nanocrystals supported on graphene were characterized by conventional transmission electron microscopy and spherical aberration (Cs)-corrected scanning transmission electron microscopy (STEM). Enhanced imaging contrast and resolution was achieved by using Cs-corrected STEM with a graphene support. In addition, clear imaging of defects and the organic-inorganic interface was enabled by utilizing this technique.

Indexing (document details)
Advisor: Korgel, Brian A.
Commitee: Chelikowsky, James, Dodabalapur, Ananth, Manthiram, Arumagam, Mulins, C. Buddie
School: The University of Texas at Austin
Department: Chemical Engineering
School Location: United States -- Texas
Source: DAI-B 74/12(E), Dissertation Abstracts International
Subjects: Physical chemistry, Chemical engineering, Materials science
Keywords: Colloidal nanocrystals, Organic electronics, Photovoltaic energy conversion, Photovoltaics, Solar cells, Surface-to-volume ratio
Publication Number: 3572875
ISBN: 978-1-303-41036-9
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