Development of Transient Attenuated Total Reflectance Spectroscopy and Investigation of Photoinduced Kinetics in Thin Films

Persistent Link:
http://hdl.handle.net/10150/268373
Title:
Development of Transient Attenuated Total Reflectance Spectroscopy and Investigation of Photoinduced Kinetics in Thin Films
Author:
Simon, Anne
Issue Date:
2012
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
The efficiency of photoconversion systems such as organic photovoltaic cells and photocatalytic water-splitting cells is largely governed by the interfacial charge transfer processes. Understanding the structure-function relationship, specifically at the molecular thin film/transparent conducting oxide interface will allow for engineering these interfaces to promote charge transfer and reduce the rate of charge recombination. Important factors that are hypothesized to influence charge transfer are morphology, chemical characteristics, electronic properties and molecular orientation. As molecules are bound to a transparent conducting oxide or incorporated into a thin film, the local solid-state molecular environment greatly influences the excited state properties of the molecule. Pathways for quenching, radiative and nonradiative decay drastically limit the excited state lifetimes. In order to investigate the photoinduced kinetics of thin films and at interfaces a instrument was developed coupling transient absorbance spectroscopy to attenuated total reflectance spectroscopy. The photoinduced kinetics of a thin film of bacteriorhodopsin was used to evaluate the instrument performance, and it was determined that 1% of a close-packed monolayer could be detected with this geometry. The properties of a molecular thin film/transparent conducting oxide were investigated by tethering zinc porphyrin to ITO. The electrochemical properties were influenced by the functional group of the binding moiety. To improve our understanding of how the solid state molecular environment affects excited states lifetimes, zinc porphyrins were incorporated into mono- and multilayer thin films and measured with transient ATR spectroscopy. Finally, multilayer films related to photocatalytic water-splitting were investigated with the incorporation of inorganic nanosheets. The nanosheets helped to create a stratified assembly for multilayer films, spatially segregating electron donor (palladium porphyrin) and electron acceptor (poly(viologen)) molecules. The role of the nanosheets in the electron transfer between the donor and acceptor was studied by monitoring the triplet state lifetimes of a palladium porphyrin with transient ATR spectroscopy.
Type:
text; Electronic Dissertation
Keywords:
Chemistry; Kinetics; Transient Absorbance
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Chemistry
Degree Grantor:
University of Arizona
Advisor:
Saavedra, S. Scott

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleDevelopment of Transient Attenuated Total Reflectance Spectroscopy and Investigation of Photoinduced Kinetics in Thin Filmsen_US
dc.creatorSimon, Anneen_US
dc.contributor.authorSimon, Anneen_US
dc.date.issued2012-
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractThe efficiency of photoconversion systems such as organic photovoltaic cells and photocatalytic water-splitting cells is largely governed by the interfacial charge transfer processes. Understanding the structure-function relationship, specifically at the molecular thin film/transparent conducting oxide interface will allow for engineering these interfaces to promote charge transfer and reduce the rate of charge recombination. Important factors that are hypothesized to influence charge transfer are morphology, chemical characteristics, electronic properties and molecular orientation. As molecules are bound to a transparent conducting oxide or incorporated into a thin film, the local solid-state molecular environment greatly influences the excited state properties of the molecule. Pathways for quenching, radiative and nonradiative decay drastically limit the excited state lifetimes. In order to investigate the photoinduced kinetics of thin films and at interfaces a instrument was developed coupling transient absorbance spectroscopy to attenuated total reflectance spectroscopy. The photoinduced kinetics of a thin film of bacteriorhodopsin was used to evaluate the instrument performance, and it was determined that 1% of a close-packed monolayer could be detected with this geometry. The properties of a molecular thin film/transparent conducting oxide were investigated by tethering zinc porphyrin to ITO. The electrochemical properties were influenced by the functional group of the binding moiety. To improve our understanding of how the solid state molecular environment affects excited states lifetimes, zinc porphyrins were incorporated into mono- and multilayer thin films and measured with transient ATR spectroscopy. Finally, multilayer films related to photocatalytic water-splitting were investigated with the incorporation of inorganic nanosheets. The nanosheets helped to create a stratified assembly for multilayer films, spatially segregating electron donor (palladium porphyrin) and electron acceptor (poly(viologen)) molecules. The role of the nanosheets in the electron transfer between the donor and acceptor was studied by monitoring the triplet state lifetimes of a palladium porphyrin with transient ATR spectroscopy.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjectChemistryen_US
dc.subjectKineticsen_US
dc.subjectTransient Absorbanceen_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplineChemistryen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorSaavedra, S. Scotten_US
dc.contributor.committeememberPemberton, Jeanneen_US
dc.contributor.committeememberArmstrong, Neal R.en_US
dc.contributor.committeememberLoy, Douglasen_US
dc.contributor.committeememberVandiver, Pamelaen_US
dc.contributor.committeememberSaavedra, S. Scotten_US
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