Browsing by Subject "OLED"

Now showing 1 - 4 of 4
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    Eco-Friendly Boron Complex Addition to Aldehydes
    (2019-08) Merritt, Marcy
    A series of aldehyde ligands were synthesized to increase yield and decrease resource use and waste production. Boron diphenyl complexes were then separately added to each of the ligands greatly increasing and shifting their intensity and fluorescence wavelength. The complexes were characterized via NMR and GCMS. The stability of these luminescent boron complexes and ability to be vacuum sublimated onto a glass surface makes them suitable for OLED application.
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    Exploration and Synthesis of Fluorescent Oxadiazole and Thiadiazole Boronyls
    (2020-09) Stadem, Samuel
    In the last decade, OLEDs have become increasingly ubiquitous in the market, already available in top-range monitors, televisions, and mobile phones. With the push for cheaper devices, much research has focused on finding new dopants to be used in these displays. Simple azole-based organoboron dyes have shown promise in this application, and our lab has investigated tetra-coordinated boron complexes of the oxadiazole and thiadiazole family. These ligands were chosen for their excellent electron transport capability and ability to make use of boron’s unique capability to form B(N,O)X type complexes. Our investigation focused on limiting the rotational sources of internal quenching, and some evidence suggests a notable bathochromic shift when chelated to with BPh2 while chelation to BF2 showed signs of a hypsochromic shift. Unfortunately, a lack of suitable instrumentation forced an end to the exploration of thiadiazole complexes. The onset of COVID-19 further stymied compound characterization, though NMR and limited fluorescence spectroscopic data on BPh2(ODP) was collected.
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    On the properties and design of organic light-emitting devices
    (2014-01) Erickson, Nicholas Carter
    Organic light-emitting devices (OLEDs) are attractive for use in next-generation display and lighting technologies. In display applications, OLEDs offer a wide emission color gamut, compatibility with flexible substrates, and high power efficiencies. In lighting applications, OLEDs offer attractive features such as broadband emission, high-performance, and potential compatibility with low-cost manufacturing methods. Despite recent demonstrations of near unity internal quantum efficiencies (photons out per electron in), OLED adoption lags conventional technologies, particularly in large-area displays and general lighting applications. This thesis seeks to understand the optical and electronic properties of OLED materials and device architectures which lead to not only high peak efficiency, but also reduced device complexity, high efficiency under high excitation, and optimal white-light emission. This is accomplished through the careful manipulation of organic thin film compositions fabricated via vacuum thermal evaporation, and the introduction of a novel device architecture, the graded-emissive layer (G-EML). This device architecture offers a unique platform to study the electronic properties of varying compositions of organic semiconductors and the resulting device performance. This thesis also introduces an experimental technique to measure the spatial overlap of electrons and holes within an OLED's emissive layer. This overlap is an important parameter which is affected by the choice of materials and device design, and greatly impacts the operation of the OLED at high excitation densities. Using the G-EML device architecture, OLEDs with improved efficiency characteristics are demonstrated, achieving simultaneously high brightness and high efficiency.
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    Strategic Synthetic Color Tuning of Oxadiazole Based Luminescent Organoboron Compounds
    (2017-05) Hines, Justin
    Many organic dopants have been created for use in SMOLED displays, but few are composed of a family of compounds that spans large portions of the visible spectrum. Through careful design, a small family of simple oxadiazole based tetra-coordinated organoboron compounds of the type B(N,O)X has been developed with emission that spans the visible spectrum from violet to green. Oxadiazole based ligands were designed and utilized for their potential for heteroatomic substitution as well as their excellent electron transport properties. Significant changes in fluorescence were observed based on the isomeric substitution of the naphthalene substituent. Minimal bathochromic emission shifts were observed when the oxadiazole ligand was chelated with BPh2, as well as minimal hypsochromic shifts when chelated to BF2. This evidence suggests the emission of the complex is affected by the isomeric position and subsequent resonance of the oxadiazole ligand. Boron clearly forms a dative bond with the lone pair from the nitrogen on the oxadiazole ring. The data shows that this coordination is susceptible to hydrolysis even with the addition of hydrophobic phenyl groups, due to the oxadiazole ring’s inherent electron deficiency and affinity for hydrogen bonding. This is evident especially in the boron trifluoride complex, in which the LCMS data shows the presence of only one fluoride atom.