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 43 for “"charge recombination"”.
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Charge recombination in organic small-molecule solar cells by Jiye Lee.
… conversion efficiency in organic solar cells, charge recombination loss needs to be minimized. First, we perform transient absorption spectroscopy to study the charge recombination dynamics of thin film bulk heterojunction of the archetype organic solar cell molecules, copper phthalocyanine …
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Aspects of charge recombination and charge transport in organic solar cells and light-emitting devices
In this thesis, aspects of charge reconbination and charge transport in organic solar cells and light-emitting devices are presented. These devices show promise relative to traditional inorganic semiconductors. We show that the energy splitting between singlet and triplet CT states in organic …
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Electron Transfer in the Reaction Center From Rhodopseudomonas Viridis (Photosynthesis, Bioenergetics, Bacteria)
… rather than the semiquinone. The kinetics of charge recombination between the photooxidized primary donor, P('+), and the photoreduced quinone acceptors were measured. The temperature dependence of the P('+) Q(,A)('-) recovery kinetic revealed a novel indirect route as well as the more typical …
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Correlation of Photocatalytic Activity with Band Structure of Low-dimensional Semiconductor Nanostructures
… low light usage efficiency and high rates of charge recombination. In this dissertation, several low-dimensional semiconductors were synthesized with hydrothermal, hydrolysis, and chemical impregnation methods. The band structures of the low-dimensional semiconductor materials were engineered …
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Understanding the properties of the interface between graphene and transition metal oxide thin films using first principle approaches
… high transparency, excellent mobility of charge carriers and is expected to be able to slow the charge recombination. Graphene/transition metal oxides nanocomposite study has become much of a wide interest recently with metal oxides like TiO2, ZnO, SnO2, etc. These metal oxides are used as …
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SYNTHESIS OF Ti02- BASED PHOTOCATALYSTS FOR PHOTOCATALYTIC H2 GENERATION
… in order to overcome the barriers of rapid charge recombination and limited light absorption range.
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On the phase transition and photo-reactivity on the micro-sized titanium dioxide single crystal.
… rate for complex reasons like defects and charge recombination rate.
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Reactions of Excited State Cationic Dyes
… subject of chapter 4. It is shown that for the charge recombination electron transfer reaction from borate anion to excited state dye cation no Marcus inverted region behavior is seen. Finally, chapter 5 is concerned with the rotational deactivation of a cyanine dye and its dependence on …
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Photoelectrochemical and photophysical studies of carbon nanotube and molybdenum disulfide based light harvesting devices
… 8 porphyrin species from 3 families to mitigate charge recombination by defects and small crystallites. A strong correlation between porphyrin species and photocurrents was observed, where interfacial porphyrins suppress charge recombination within MoS2 nanolayers, thus enhancing the …
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Photosynthetic antenna-reaction-center mimicry
… excitation energy to the reaction center where charge separated entities are formed via photoinduced electron transfer (PET). The synthesized artificial molecular systems are comprisedof porphyrin-fullerene, donor-acceptor entities due to their well studied photophysical properties which are …
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Excited State Dynamics and Energy Transfer Studies of Aromatic Molecules
… important for the efficiency of the energy and charge transfer events, which are the critical elements of light harvesting devices. Additionally non-radiative events can compete with the desired energy storage processes. A series of dendrimers composed of meta-conjugated phenylethynylene has …
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Excited states and electron transfer in solution : models based on density functional theory
… First, we apply constrained DFT to characterize charge recombination in a photoexcited donor-acceptor dyad and to understand the photophysical behavior of a fluorescent sensor for aqueous zinc. Second, we discover that the delta-self-consistent-field ([Delta]SCF) approach to excited states in DFT …
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Advances in Phenyl-Modified Carbon Nitride: Towards Sustainable Environmental Applications
… composition. However, limitations such as poor charge separation and limited light absorption have hindered its practical use. To address these challenges, recently researchers have introduced phenyl groups into the carbon nitride framework, which enhanced its optoelectronic properties and …
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Spectroscopic Studies of Charge Dynamics in Non-Fullerene Organic Solar Cells
… achieved. Furthermore, they have shown efficient charge separation with negligible energy loss, overcoming one of the crucial limitations of fullerene based OSC. Here, we present a study on the charge generation, separation, and recombination dynamics of non-fullerene solar cells. We investigate …
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Photosynthesis-inspired device architectures for organic photovoltaics
… and (2) low open-circuit voltage due to charge recombination at the donor-acceptor interface. In this work, we demonstrate two new device architectures inspired by photosynthesis that aim to overcome these two challenges. First, we overcome the trade-off between light absorption and …
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Microstructured Halide Perovskites for Energy Applications
… polycrystalline one, where the high density of charge traps due to grain boundaries presents a major challenge. These traps not only compromise the device’s efficiency but also accelerate its degradation. To overcome these limitations, single-crystal structures have been developed. These are …
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Iron-Doped Titanium Dioxide Nanomaterials: Synthesis, Characterization and Photodegradation Catalytic Behavior
… of changes in the materials potential of zero charge (PZC) and how surface charge affects the dye adsorption. Using the Langmuir-Hinshelwood model, rate constants (kobs) decreasing with an increase in the molar percentage of iron in TiO2 as well as a decrease in the materials band gap. This …
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Inhibitor-Quinone Interactions in Reaction Centers From Rhodopseudomonas Sphaeroides (Herbicide, Triazine, Ubiquinone, Photosynthesis, Resistance)
… Rhodopseudomonas sphaeroides were studied. The charge recombination pathway between the primary electron donor, P, and the primary ubiquinone electron acceptor, Q(,A), or the secondary ubiquinone acceptor, Q(,B), was established, allowing the determination of the free energy change for the …
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Effects of Low Temperature and Structure on the Photophysics of Alkylammonium Lead Halide Semiconductors
… structures and magnetic fields on charge recombination in organic photovoltaics (OPVs). The applications of the systems studied vary from photodetectors, to LEDs, lasers and solar cells. We synthesised Cs2CuCl4 and CsCuCl3 nanoparticles. By varying the ratio of coordination solvents …
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Nanocarbons as charge carriers in organic solar cells
… to the enhancement of OPV performance, such as charge carrier mobility, thermal conductivity, mechanical strength, increased optical absorption and solubility in organic solvents. Nanocarbons also can improve the morphology of the active layer, which is critical to the optimization of OPV …
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