Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 27 for “"delayed fluorescence"”.
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Flash-Photolytic Studies of Delayed Fluorescence From Aromatic Hydrocarbons
Made available in DSpace on 2014-12-13T20:10:15Z (GMT). No. of bitstreams: 1 7804071.pdf: 6991956 bytes, checksum: 79a1b0f7707bc8c709f2b3ca45858761 (MD5) Previous issue date: 1977
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Thermally Activated Delayed Fluorescence Emitters: Molecular Design, Photophysics, and Sensing Application
Thermally activated delayed fluorescence (TADF) is a strategy for harvesting both singlet and triplet excitons in some purely organic emitters and is attracting increasing interest beyond their use in organic light-emitting diodes (OLEDs), including chemical sensing. In this thesis, coumarin-based …
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Delayed fluorescence as a probe of radiationless transitions in anthracene and algae
The delayed fluorescence emitted by both crystalline anthracene and chlorophyll a in algae is studied. In the case of crystalline anthracene, the blue light-excited delayed fluorescence is used to study the temperature dependence of monomolecular intersystem crossing. The associated rate constant k …
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Data-driven Materials Informatics for Optoelectronics: From Natural Language Processing to Predictive Modelling of TADF Molecules
… with a focus on thermally-activated delayed fluorescence (TADF). Chapter 1 provides an introduction to the background and recent progress in data-driven methods in materials sciences and thermally-activated delayed fluorescence. Chapter 2 reviews the natural language processing …
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Photon Generation and Dissipation in Organic Light-Emitting Diodes
By using phosphorescent and thermally activated delayed fluorescence emitters, the internal quantum efficiency of organic light-emitting diodes (OLEDs) can now reach 100%. However, a major fraction of generated photons is trapped inside the device, because of the intrinsic multi-layer device …
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The design and synthesis of organic chromophores for Faraday rotation and photoluminescence
… properties including Faraday rotation and delayed fluorescence. In Chapter 1, we introduce the magneto-optical property Faraday rotation. The current frontiers in performance, applications, and mechanistic understanding of Faraday rotation in organic-chromophore thin-films is discussed. …
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Coinage Metal Chalcogenide Clusters with N-Heterocyclic Carbene Ancillary Ligands
… molecular rigidity and thermally activated delayed fluorescence. Quantum chemical calculations point to a common mode of emission from all clusters, originating from a charge transfer process from metal-chalcogenide core to the NHC ancillary ligands.
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Science and Engineering of Spin Triplet Excitons in Luminescent Molecular Semiconductors
… present an optical study of thermally activated delayed fluorescence (TADF) in the near infrared emitter CAT-1. We demonstrate TADF at a lower energy than had before been realised, verifying a simple molecular design concept that pushes the boundary of TADF. We then begin spin-sensitive studies …
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Harnessing Vibrations for Efficient Exciton Dynamics in Semiconducting Energy Materials
… of several archetypal thermally-activated delayed-fluorescence emitters. We reveal their excited-state vibrations and track changes over time due to environmental relaxation. This serves to rationalize favourable emission bandwidths, low Stokes shifts, low non-radiative rates, and …
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Photophysics of small molecule organo-metallic complexes for OLED applications
… phosphorescence and organic Thermally Activated Delayed Fluorescence (TADF). The incorporation of both sets of physical processes which have previously allowed emission from triplet states has resulted in a class of materials with near 100% photoluminescence and internal device efficiencies, and …
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Histone modifications and the Arabidopsis thaliana circadian clock
… by measuring their circadian leaf movement and delayed fluorescence (DF) rhythms. GCN5/ HAG1 mutant plants (gcn5) exhibited erratic TOC1 expression in both constant dark (DD) and constant light (LL) conditions. Although TOC1 expression appeared to be rhythmic in both DD and LL conditions, the …
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Electronic processes in organic optoelectronics : insights gained through modeling and magnetic field effects
… interfaces in OPVs. Thermally activated delayed fluorescence (TADF) is becoming an increasingly important OLED technology that extracts light from non-emissive triplet states via reverse intersystem crossing (RISC) to the bright singlet state. We use MFEs to prove a rather surprising …
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Naujų pirimidino - fenoksazino TADF spinduolių sintezė ir tyrimas /
Thermally activated delayed fluorescence (TADF) is an attractive way to achieve 100% internal fluorescence quantum yield without involving any expensive heavy atoms by converting all excitations to singlet ones by thermal activation. Usually, this is achieved by constructing TADF molecules with …
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Spectroscopic Studies of Excited States in Carbene-Metal-Amide Emitters
… in CMAs occurs through thermally activated delayed fluorescence (TADF). In contrast to usual TADF emitters, CMAs incorporate a metal centre which enhances spin-orbit coupling effects. However, the in-depth emission mechanism in CMAs has been subject to some uncertainty, and high-performing …
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On the Colour Tuning and Stability of Carbene-Metal-Amide Organic Light-Emitting Diodes
… which luminescence through a thermally activated delayed fluorescence mechanism. CMAs have been previously incorporated into highly efficient green OLEDs. In chapter 4, CMAs are first chemically modified through the addition of electron donating and withdrawing groups on the carbazole. The …
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Study of Triplet Exciton Dynamics in Small Organic Molecule Films Using Time Resolved Optical Spectroscopy
… multilayer structures were studied by measuring fluorescence, delayed fluorescence and phosphorescence. 4,4’-N,N’-dicarbazolyl-1,1’-biphenyl (CBP) widely used in organic light emitting diodes is characterized. Evidence is provided that in some of these spectra emission comes from trap states …
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Palladium-catalyzed C-N cross-coupling and application to the synthesis of delayed singlet emitters for OLED development
… series of compounds could potentially be used as delayed singlet emitters for organic light emitting devices. Chapter 1. Palladium-Catalyzed Amidation of Five-Membered Heterocyclic Bromides Palladium-catalyzed C-N cross-coupling between primary amides and five-membered heterocyclic bromides that …
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I. Kinetic Modeling of Surface Reactions II. Computational Design of Organic Semiconductors
… we are interested in thermally activated delayed fluorescence (TADF) and triplet-triplet annihilation (TTA), which convert the nonemissive triplet excitons into emissive singlet excitons. First, we introduce a simple four-state model of TADF. The model predicts that it is possible to …
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Systematic improvement and applications of density functional theory in complex chemical systems
… computational design of new thermally activated delayed fluorescence (TADF) materials using conventional time-dependent DFT method, while point out the need for better excited-state DFT methods. Finally, we develop efficient computational screening protocols to study TADF materials based on a …
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Exciton dynamics in organic semiconductors for efficient electroluminescent devices
… In the first part of the thesis, ‘hyperfluorescence’, which is the concept that thermally activated delayed fluorescence (TADF) materials are exploited as an exciton sensitiser to a fluorescent emitter, is investigated. Firstly, the possibility of excluding the host matrix is …
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