Rod-like plasmonic nanoparticles as optical building blocks: how differences in particle shape and structural geometry influence optical signal

dc.contributor.advisor Ning Fang Stender, Anthony
dc.contributor.department Chemistry 2018-08-11T09:19:00.000 2020-06-30T02:48:58Z 2020-06-30T02:48:58Z Tue Jan 01 00:00:00 UTC 2013 2015-07-30 2013-01-01
dc.description.abstract <p>Gold nanoparticles, particularly those with an anisotropic shape, have become a popular optical probe for experiments involving work on the nanoscale. However, to carry out such delicate and intricate experiments, it is first necessary to understand the detailed behavior of individual nanoparticles. In this series of experiments, optical and electron microscopy were utilized for the characterization of individual nanoparticles and small assemblies of nanoparticles.</p> <p>In the first experiment, gold nanorods were investigated. Single, isolated nanorods exhibit two maxima of localized surface plasmon resonance (LSPR), which are associated with the two nanorod axes. Upon the physical rotation of a nanorod at one of its LSPR wavelengths under polarized illumination, the optical behavior varies in a sinusoidal fashion. A dimer of nanorods exhibits optical behavior quite similar to a nanorod, except the LSPR maxima are shifted and broader. Under differential interference contrast (DIC) microscopy, a pair of nanorods separated by a distance below the diffraction limit can be distinguished from a single nanorod due to its optical behavior upon rotation. Dark field microscopy is unable to distinguish the two geometries.</p> <p>For the second set of experiments, the optical behavior of single gold nanorods at non-plasmonic wavelengths was investigated. The same nanorod was rotated with respect to a polarized light source under DIC, dark field, and polarized light microscopy. DIC microscopy was found to produce diffraction pattern peaks at non-plasmonic wavelengths, which could be altered by adjusting the setting of the polarizer.</p> <p>In the third set of experiments, the optical behavior of a single gold dumbbell and several simple dumbbell geometries were investigated with microscopy and simulations. The single dumbbell displayed behavior quite similar to that of a nanorod, but dumbbells exhibit a shift in both LSPR wavebands. Moreover, the shape of dumbbell particles allows them to interlock with one another quite easily. The dimers that form as a result display optical behavior that differs from what has been previously reported about nanorod dimers. Simulated surface charge density patterns reveal that hybridization of LSPR modes occurs readily along the lobes of individual dumbbells in some situations. A pentamer of dumbbells also displays hybridization of modes, and "hot spots" are observed at junctions between pairings of dumbbells.</p> <p>In the final set of experiments, the assembly behavior of nanoparticles in solution was observed in real time. In general, large assemblies of nanoparticles display backbone-like rigidity, but an interesting variety of movements is permitted within the larger structures.</p>
dc.format.mimetype application/pdf
dc.identifier archive/
dc.identifier.articleid 4338
dc.identifier.contextkey 4615830
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath etd/13331
dc.language.iso en
dc.source.bitstream archive/|||Fri Jan 14 19:50:13 UTC 2022
dc.subject.disciplines Analytical Chemistry
dc.subject.disciplines Mechanics of Materials
dc.subject.disciplines Nanoscience and Nanotechnology
dc.subject.keywords Assembly
dc.subject.keywords Microscopy
dc.subject.keywords Nanoparticle
dc.subject.keywords Nanorod
dc.subject.keywords Plasmon
dc.subject.keywords Specroscopy
dc.title Rod-like plasmonic nanoparticles as optical building blocks: how differences in particle shape and structural geometry influence optical signal
dc.type article
dc.type.genre dissertation
dspace.entity.type Publication
relation.isOrgUnitOfPublication 42864f6e-7a3d-4be3-8b5a-0ae3c3830a11 dissertation Doctor of Philosophy
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