Localized surface plasmon resonance spectroscopy of gold and silver nanoparticles and plasmon enhanced fluorescence

dc.contributor.advisorWillets, Katherine A.en
dc.contributor.committeeMemberBrodbelt, Jennifer S.en
dc.creatorVokac, Elizabeth Anneen
dc.date.accessioned2012-02-16T19:26:21Zen
dc.date.available2012-02-16T19:26:21Zen
dc.date.issued2011-12en
dc.date.submittedDecember 2011en
dc.date.updated2012-02-16T19:26:34Zen
dc.descriptiontexten
dc.description.abstractThis thesis presents spectroscopic studies of metallic nanoparticle localized surface plasmons and plasmon enhanced fluorescence. We investigated the dielectric sensitivity of silver nanoprisms to an external electric field and gold nanorods to the formation of a self-assembled surface monolayer. Dark field microscopy was used to image plasmonic scattering from single nanoparticles, and a liquid crystal tunable filter was used to construct corresponding spectra. The plasmon resonances of silver nanoprisms displayed both reversible red shifts and irreversible blue shifts along with drastic intensity changes upon exposure to an applied bias. The plasmon resonances of gold nanorods showed sensitivity to the presence of alkanethiol molecules adhered to the particle surface by a moderate red shift. An increase in the effective external dielectric caused a shift toward longer wavelengths. We imaged plasmon enhanced fluorescence in order to optimize experimental parameters for a developing project that can characterize nanoparticle structure on sub-wavelength dimensions. Preliminary controls were performed to account for the effect of O₂ plasma treatment, solvent and alkanethiol monolayer formation on surface plasmon resonances. We found that O₂ plasma treatment for different time intervals did not result in a plasmon shift compared to untreated nanoparticles exposed to N₂; however when exposed to solvent the surface plasmons of the treated particles shifted five times as far toward the red. Interestingly, the solvent effect only resulted in a plasmon shift when the particles were N₂ dried after solvent incubation. Gold nanorods incubated in ethanol showed no wavelength maximum shift in pure solvent over time, but shifted moderately to the red after incubation in a solution of alkanethiol molecules. Conditions for the plasmon enhanced fluorescence study were optimized using a dye conjugate of the same alkanethiol molecule used previously by formation from solution in a monolayer on the gold nanorod surface. The appropriate synthesis for dye functionalization, molecular concentrations, solvents and optical settings were determined.en
dc.description.departmentChemistryen
dc.format.mimetypeapplication/pdfen
dc.identifier.slug2152/ETD-UT-2011-12-4511en
dc.identifier.urihttp://hdl.handle.net/2152/ETD-UT-2011-12-4511en
dc.language.isoengen
dc.subjectPlasmonicsen
dc.subjectNanoparticleen
dc.subjectLSPRen
dc.subjectGolden
dc.subjectSilveren
dc.subjectFluorescenceen
dc.titleLocalized surface plasmon resonance spectroscopy of gold and silver nanoparticles and plasmon enhanced fluorescenceen
dc.type.genrethesisen
thesis.degree.departmentChemistryen
thesis.degree.disciplineChemistryen
thesis.degree.grantorUniversity of Texas at Austinen
thesis.degree.levelMastersen
thesis.degree.nameMaster of Artsen
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