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dc.contributor.authorSiitonen, Anni
dc.date.accessioned2010-11-09T13:33:08Z
dc.date.available2010-11-09T13:33:08Z
dc.date.issued2010
dc.identifier.isbn978-951-39-4063-8
dc.identifier.otheroai:jykdok.linneanet.fi:1142048
dc.identifier.urihttps://jyx.jyu.fi/handle/123456789/25574
dc.description.abstractThe unique nature of optical properties of single-walled carbon nanotubes (SWCNT), together with their promising potential applications, have created enormous interest towards the photophysics of SWCNT. Many aspects of carbon nanotubes originate from the electronic structure of carbon honeycomb lattice and one-dimensionality. SWCNTs exist in various chiral structures and diameters, which the optical and electrical properties are dependent on. It has been discovered that SWCNT excited states are excitonic with strong Coulomb interaction between the electron and the hole. However, many features of excitons are not yet well defined, such as absorption cross-sections, fluorescence quantum yields, exciton lifetimes, and the nature of exciton mobility. The cylindrical shape with all atoms on the surface makes SWCNTs highly sensitive to environment which is a significant factor affecting the optical properties. First part of this thesis concentrates on the temperature dependence of excitonic absorption transitions. The importance of this study lies in the complexity of environmentally induced mechanisms to alter the energy gap and shift the electronic absorption transitions as a function of temperature. The results revealed abrupt shift in the energy gap interpreted to originate from interactions with water. The second part discusses the processes occurring after absorption: exciton mobility and dynamics. By analyzing reactions between single-molecule diazonium salt and individual nanotubes, the distance travelled by exciton during its lifetime, in different surfactants and for different chiral structures was determined. The results indicate that localized excitons have diffusional motion along the nanotube axis. The large diffusion ranges obtained (160 - 340 nm) explain the sensitivity of SWCNT emission to changes in local environment. The dynamics of excitons were studied with excitation dependence measurements. Results revealed the existence of long lived states that act as quenchers of emission even at relatively low excitation intensities.en
dc.format.extent56, [38] s.
dc.language.isoeng
dc.publisherUniversity of Jyväskylä
dc.relation.ispartofseriesResearch report / Department of Chemistry, University of Jyväskylä
dc.relation.isversionof56, [38] s.
dc.subject.othereksitonin diffuusio
dc.subject.otherhiilinanoputket
dc.subject.otherFourier transform infrared (FTIR) spectroscopy
dc.subject.otherexciton diffusion
dc.subject.otherexciton dynamics
dc.subject.otherfluorescence spectroscopy
dc.subject.otherfluorescence microscopy
dc.subject.othercarbon nanotubes
dc.subject.otherspectroscopy
dc.titleSpectroscopic studies of semiconducting single-walled carbon nanotubes
dc.typeDiss.fi
dc.identifier.urnURN:ISBN:978-951-39-4063-8
dc.type.dcmitypeTexten
dc.type.ontasotVäitöskirjafi
dc.type.ontasotDoctoral dissertationen
dc.contributor.tiedekuntaMatemaattis-luonnontieteellinen tiedekuntafi
dc.contributor.tiedekuntaFaculty of Mathematics and Scienceen
dc.contributor.laitosKemian laitosfi
dc.contributor.yliopistoUniversity of Jyväskyläen
dc.contributor.yliopistoJyväskylän yliopistofi
dc.contributor.oppiaineKemiafi
dc.relation.issn0357-346X
dc.relation.numberinseriesNo. 139
dc.rights.accesslevelopenAccessfi
dc.subject.ysofysikaalinen kemia
dc.subject.ysooptiset laitteet
dc.subject.ysospektroskopia
dc.subject.ysofluoresenssi
dc.subject.ysoabsorbtio
dc.subject.ysolämpötila
dc.subject.ysoliuottimet
dc.subject.ysokemialliset reaktiot


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