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 “"colloidal synthesis"”.
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Synthesis, Characterisation and Functionalisation of CdSe Quantum Dots
… a number of different processes ranging from colloidal synthesis to electrochemical methods to chemical vapour deposition (CVD). This thesis focuses on the synthesis of high-quality CdSe nanocrystals through a bench- top colloidal synthesis paying particular attention to the effects of varying …
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Mesoporous silica encapsulated metal nanoparticles in catalysis
… structure-property studies in catalysis. Direct colloidal synthesis of intermetallic nanoparticles requires the presence of organic capping agents, which limits the thermal stability of nanoparticles and complicates their surface structures. Mesoporous silica shells can be used to encapsulate …
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Studies on the Preparation and Luminescence Properties of Cadmium Selenide Quantum Dots, Their Immobilization, and Applications.
… selenide quantum dots were synthesized via colloidal synthesis. Contrary to previous preparations, more focus was placed on the temperature rather than the duration of time at which they form. A series of colored solutions were obtained because the excited quantum dots of various sizes …
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Studies on the Preparation, Immobilization, and Luminescence Properties of Zinc Oxide (ZnO)Quantum Dots
… through an ethanol based precipitation via colloidal synthesis method at various pH values. Various emission colors were obtained because the excited quantum dots of various sizes emitted specific wavelengths of light. The emission spectra indicated that the pH dependent quantum dots were …
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Exploring and enhancing conductivity in semiconductor nanoparticle films
… tune with particle size. NCs formed via colloidal synthesis are suspended in solution by the organic ligands which passivate the NC surface after synthesis, and NCs can be deposited from solution to form NC solids. In theory, 'designer solids' having different electrical properties can be …
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HIGH TEMPERATURE ZnSe:Mn/ZnS NANOPHOSPHORS WITH VERY HIGH QUANTUM EFFICIENCY FOR WHITE LEDs
… above room temperature. A novel technique for colloidal synthesis of ZnSe:Mn/ZnS nanocrystals (NCs) is also presented here, using a growth doping technique that exhibits a bright emission peak at 587 nm with excellent thermal behavior and record high quantum efficiency. The 587 nm peak from the …
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Size-binary Zincblende: A Colloidal Approach to Omnidirectional Photonic Bandgaps
Binary colloidal mixtures have the potential to greatly expand the range of mesoscale structures fabricated by self-assembly, putting them at the frontier of the realization of novel photonic crystals. Currently, it is not understood how the multicomponent basis and particle size ratio of binary …
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Integration of CdSe/ZnS Quantum Dots into As-induced Etched Nanovoids on GaSb
… to emit into the UV or into the infra-red. The colloidal synthesis of CdSe/ZnS quantum dots is presented, to describe their incorporation into nanovoids formed on GaSb membranes. Nanoscale etch-pit formation on GaSb surfaces happens as a result of arsenic (As2) based in situ etch technique. The …
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Direct imaging of self-assembly behaviors of colloids: from the microscale plates to the nanoscale cubes
Microscale and nanoscale colloidal particle self-assembly is widely studied to establish the design rules towards ordered structures and used as atomic model systems for phase transition studies such as crystallization and growth. The well-established synthetic library enables the synthesis of …
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Semiconductor nanocrystals : synthesis, mechanisms of formation, and applications in biology
The primary focus of this thesis is the synthesis and applications of semiconductor nanocrystals, or quantum dots (QDs). Novel synthetic routes to ternary 1-III-VI QDs are presented, and we report the first highly luminescent Cu-In-Se QDs spanning the red to near-infrared region. The synthetic …
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Interactions of cadmium selenide (CdSe) quantum dots with coagulant proteins extracted from Moringa oleifera seeds
… oxide (TOPO) and Trioctyl phosphene (TOP) using colloidal synthesis. The purified mesoporous M. oleifera seeds coagulant protein (MOCP) with a surface area of 8.4134 m2/g, was extracted from M. oleifera seeds. The interaction mechanism between CdSe QDs and MOCP was studied using the Ultraviolet …
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Polymer and metallodielectric based photonic crystals
The bottom-up colloidal synthesis of photonic crystals has attracted interest over top-down approaches due to their relatively simplicity, the potential to produce large areas, and the low-costs with this approach in fabricating complex 3-dimensional structures. This thesis focuses on the bottom-up …
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Surface chemistry and material integration of metal oxide nanocrystals
… physical parameters can be achieved through colloidal synthesis. In this process, small nuclei form in a heated mixture and long organic molecules known as ligands, which are typically amines or carboxylates, regulate their growth. These ligands also provide long term stability to the …
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Atomistic investigation of morphology and optoelectronic properties of bismuth sulfide nonostructures
… of factors. Its non-toxicity, low cost synthesis and high absorption properties make Bi2S3 a promising material for several application, such as solid-state semiconductor-sensitized solar cells. The intrisic anisotropy in the crystal structure of this material facilitates the formation …
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A FACILE SYNTHESIS OF TRANSITION METAL OXIDE AND CHALCOGENIDES NANOCRYSTALS FOR ELECTROCATALYTIC APPLICA TIONS
… reactions. However, nanocrystals by conventional synthesis methods are either highly aggregated or capped with excessive insulating surfactant, resulting in inconsistent electrochemical performance and capacity lost in charge/discharge cycling. In this thesis, we present a general colloidal …
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Controlled Synthesis and Characterization of Magnetic Chalcospinels Nanocrystals
… also provided an overview of the wet-chemical colloidal methods as an important approach to size and shape-controlled synthesize of nanocrystals. We have also discussed the importance of metal doping reactions as a pathway to create previously unavailable multielemental materials for …
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Exploring charge carrier dynamics in quantum dot and double heterojunction nanorod light emitting devices using transient electroluminesence measurements
… band gap, compatibility with scalable bottom-up colloidal synthesis techniques, and ability to be processed using simple solution-based deposition techniques. Light emitting devices (LEDs) fabricated utilizing these materials have already demonstrated competitive performance with their organic …
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Colloidal Self-Assembly of Novel Materials Displaying Structural Colour
… of colloids is a powerful technique for the synthesis of novel materials. While top-down manufacturing methods can also produce structures patterned on the mesoscale, they are frequently limited in resolution, slow to employ or restricted to two-dimensional systems; in contrast, self-assembly …
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Atomic Scale Characterisation of Pt-Re/CeO2 for the Water Gas Shift Reaction
… of both metals on the catalyst support. Colloidal synthesis methods provide a way to ensure the platinum and rhenium are in close contact with each other. Literature has reported a method to produce homogeneously alloyed Pt3Re nanoparticles. It was hypothesised that using the colloidal …
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Novel Precursors for the Synthesis of Metal Selenide Nanoparticles, Thin Films and Alloys
… advantageous, as they can be used for the synthesis of metal chalcogenide nanocrystals, and are equally suitable for the deposition of thin films. Furthermore, a better control over stoichiometry and phase can be achieved, due to preformed bonds between metal and chalcogen atom. Numerous …
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