Characterization and optimization of novel materials and interfaces in organic electronic devices

Persistent Link:
http://hdl.handle.net/10150/280511
Title:
Characterization and optimization of novel materials and interfaces in organic electronic devices
Author:
Flora, Ware Howard
Issue Date:
2004
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 research embodied in this text involves the characterization and optimization of novel materials and interfaces critical to the performance of organic electronic devices: Thrust 1. A scheme for elucidating the relative significance of energy vs. charge transfer (ET vs. CT) routes to guest dye emission in organic light-emitting diodes (OLEDs) was developed using near-IR emissive phthalocyanine (Pc) or naphthalocyanine (NPc) dopants. CT processes were observed to occur by an oxidized guest mechanism, which may be predicted from the solution electrochemistry of these materials. Additionally, a new series of quinacridone(QA)-based guest dyes were developed/characterized, modified at the N,N' positions to form four generations of Frechet dendrimers and their t-butyl-terminated analogues. As generation number increases, they exhibited decreased aggregation and increased luminescence efficiencies in the condensed phase. In solution, sharply declining rates of heterogeneous electron transfer were observed. Despite this trend, when these new molecules were doped into OLEDs, ET and CT routes to QA emission were not significantly inhibited. Thrust 2. A series of hybrid metal cluster-organic materials containing between one and seven [Re6(mu3-Se)8] 2+ clusters per molecule were electrochemically characterized. Dimer, trimer, and tetramer assemblies yielded uncoupled cluster oxidations. For cluster 7-mer dendrimers, uncoupled oxidations were observed for unconjugated linking groups, while coupled oxidations were observed with a conjugated linker, suggesting through-bond electrical polarization of the interior cluster. Thrust 3. The first UV-Vis attenuated total reflectance (ATR) method for the simultaneous determination of molecular tilt and azimuthal rotation for ultra-thin films of molecules with circularly-polarized electronic transition dipoles was developed, where a priori assumptions of the mean molecular orientation of either angle are not necessary in order to recover both mean angles. A model Pc-based system was evaluated, where this material is known to form in-plane molecular columns. Assuming a delta distribution in the orientation of each angle, it was determined that the mean tilt of the molecular plane away from the substrate surface is 80 ± 3°, and the mean azimuthal rotation of the molecular plane away from the column direction is 56.9 ± 0.8°. The dependence of molecular orientation on environmental exposure conditions and surface premodifiers was also evaluated.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Chemistry, Analytical.; Chemistry, Physical.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Chemistry
Degree Grantor:
University of Arizona
Advisor:
Armstrong, Neal R.

Full metadata record

DC FieldValue Language
dc.language.isoen_USen_US
dc.titleCharacterization and optimization of novel materials and interfaces in organic electronic devicesen_US
dc.creatorFlora, Ware Howarden_US
dc.contributor.authorFlora, Ware Howarden_US
dc.date.issued2004en_US
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 research embodied in this text involves the characterization and optimization of novel materials and interfaces critical to the performance of organic electronic devices: Thrust 1. A scheme for elucidating the relative significance of energy vs. charge transfer (ET vs. CT) routes to guest dye emission in organic light-emitting diodes (OLEDs) was developed using near-IR emissive phthalocyanine (Pc) or naphthalocyanine (NPc) dopants. CT processes were observed to occur by an oxidized guest mechanism, which may be predicted from the solution electrochemistry of these materials. Additionally, a new series of quinacridone(QA)-based guest dyes were developed/characterized, modified at the N,N' positions to form four generations of Frechet dendrimers and their t-butyl-terminated analogues. As generation number increases, they exhibited decreased aggregation and increased luminescence efficiencies in the condensed phase. In solution, sharply declining rates of heterogeneous electron transfer were observed. Despite this trend, when these new molecules were doped into OLEDs, ET and CT routes to QA emission were not significantly inhibited. Thrust 2. A series of hybrid metal cluster-organic materials containing between one and seven [Re6(mu3-Se)8] 2+ clusters per molecule were electrochemically characterized. Dimer, trimer, and tetramer assemblies yielded uncoupled cluster oxidations. For cluster 7-mer dendrimers, uncoupled oxidations were observed for unconjugated linking groups, while coupled oxidations were observed with a conjugated linker, suggesting through-bond electrical polarization of the interior cluster. Thrust 3. The first UV-Vis attenuated total reflectance (ATR) method for the simultaneous determination of molecular tilt and azimuthal rotation for ultra-thin films of molecules with circularly-polarized electronic transition dipoles was developed, where a priori assumptions of the mean molecular orientation of either angle are not necessary in order to recover both mean angles. A model Pc-based system was evaluated, where this material is known to form in-plane molecular columns. Assuming a delta distribution in the orientation of each angle, it was determined that the mean tilt of the molecular plane away from the substrate surface is 80 ± 3°, and the mean azimuthal rotation of the molecular plane away from the column direction is 56.9 ± 0.8°. The dependence of molecular orientation on environmental exposure conditions and surface premodifiers was also evaluated.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectChemistry, Analytical.en_US
dc.subjectChemistry, Physical.en_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.advisorArmstrong, Neal R.en_US
dc.identifier.proquest3131597en_US
dc.identifier.bibrecord.b46711363en_US
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