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 22 for “"Colloidal nanocrystals"”.
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Hybrid optoelectronics with colloidal nanocrystals
… spectroscopic studies of the exciton dynamics in colloidal spherical cadmium sulfide CdS nanocrystals (NC) in the vicinity of a single indium gallium nitride InGaN quantum well (QW) in dependence of temperature. QWs of the alloy material InGaN exhibit a dependence of the exciton dimensionality on …
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Ultrafast Optical Spectroscopy Techniques applied to colloidal nanocrystals
… optical spectroscopy techniques applied to colloidal nanocrystals. Colloidal semiconductor nanocrystals in recent years have attracted a lot of attention in particular in optoelectronic applications, because they present unique optical, electronic and charge carrier transport properties that …
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First-principles studies of defects in colloidal nanocrystals
… lead halide perovskite PV, organic PV and colloidal quantum dot (CQD) PV. Colloidal quantum dots are semiconducting nanocrystals that exhibit size tunable electronic and optical properties.
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Synthesis and characterization of cerium-doped lanthanum halide colloidal nanocrystals
… bromide/undoped lanthanum fluoride core/shell nanocrystals through inexpensive and repeatable colloidal routes. Following a systematic approach, cerium-doped lanthanum fluoride colloidal nanocrystals were synthesized through water-based and water-free (anhydrous) routes. Furthermore, core/shell …
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Infrared-to-visible upconversion in hybrid thin films of colloidal nanocrystals and organic molecules
… device consists of a monolayer of lead sulfide colloidal nanocrystals (NCs) and a thin film of rubrene mixed with emissive DBP molecules. Upconversion is realized via triplet-triplet annihilation (TTA) in rubrene sensitized by the NCs. We demonstrate that compared to the previous all-molecular …
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Novel synthetic routes to high-quality II-VI colloidal nanocrystals : controlled growth using mild precursors in the presence of selected ligands
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2004.
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Excitonic spin engineering in optoelectronic devices
… with tetracene as the fission material and PbS colloidal nanocrystals as the acceptor. We demonstrate that low energy excitons generated in the fission material transfer to the nanocrystal with 90% efficiency before fluorescing. This fluorescence will be able to transfer energy to inorganic …
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Quantum diamonds : a discussion of the chemistry, materials science, physics and applications of ternary (Cu-In-S) nanocrystals
… thesis explores the synthesis and properties of colloidal nanocrystals composed of the non-toxic semiconductor copper indium sulfide (CulnS₂). We report an improved core nanoparticle synthesis with unique compositional control, a rationally-designed precursor for the synthesis of high-quality …
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Singlet exciton fission : applications to solar energy harvesting
… which has not been demonstrated. I prove that colloidal nanocrystals accept triplet excitons from the singlet fission molecule tetracene. This enables future devices where the combine singlet fission material and nanocrystal system energy transfer triplet excitons produced by singlet fission to …
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A hybrid approach towards on-chip visible lasers
… has expanded to include organic molecules; colloidal nanocrystals such as quantum dots, quantum rods, and quantum wells or nanoplatelets; perovskite semiconductors; and perovskite nanocrystals. A key feature of these materials is the capability to engineer their energy levels, e.g., via …
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Spectral properties of semiconductor nanocrystals and their applications
… the optical properties of the semiconductor nanocrystals by controlling their growth - size, shape, materials, coatings, etc - makes them appealing for many optical applications. Despite the impressive development of nanocrystal manufacturing capabilities, there are still many basic questions …
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Heavy-metal-free colloidal nanocrystal heterostructures – synthetic chemistry and growth mechanisms
Building heterostructures of colloidal nanocrystals by bringing different components into contact can improve existing or impart novel properties, which enables applications as light emitters in already-commercialized and near-future products. However, the majority of the research has been based on …
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Optical Properties of Colloidal II-VI and III-V Semiconductor Nanocrystals: Single Nanocrystal Photon Correlation Spectroscopy
Colloidal nanocrystals (NCs), also known as quantum dots, are nanometer-sized semiconductor crystalline structures comprised of thousands to tens of thousands of atoms placing them in a world between the molecular-sized and the bulk-sized world, allowing them to harness unique qualities from both. …
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Specific loss power optimization in metal ferrite nanocrystals for radiofrequency stimulation of neurons
… losses in superparamagnetic metal ferrite nanocrystals are modeled to determine the optimal operating parameters for dissipation of heat. Optimal nanocrystals are then synthesized via high-temperature thermolysis of a mixed metal oleate precursor, and stabilized in the aqueous phase through …
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Surface functionalisation techniques for colloidal inorganic nanocrystals
Colloidally-stable inorganic nanocrystals have a wide range of envisaged applications in biological environments. To reach their potential, the nanocrystals need to be stable in aqueous environments and have pendant functionality available for attachment of biomolecules. In this thesis, new methods …
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Synthesis of derivatizable semiconductor nanocrystals through rational ligand design, and applications thereof
Over the last decade, the synthesis methods of colloidal nanocrystals have advanced at an astonishing rate, producing particles that are chemically stable, monodisperse, and, in the case of semiconductor quantum dots (QDs), immensely bright. Inorganic nanocrystals linked to functional organic or …
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Controlled Synthesis and Characterization of Magnetic Chalcospinels Nanocrystals
… binary and ternary metal chalcogenides and their nanocrystals has been provided. We have 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 …
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Engineering Nanocrystal Devices Through Cation Exchange And Surface Modifications
Colloidal nanocrystals (NCs) are promising materials for electronics and optoelectronics, due to their (i) solution processability; (ii) size-dependent electronic band structures; and (iii) large surface-to-volume ratio. Exploring these features has led to great advances in our fundamental …
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Excited State Dynamics of Dyes Bound to Nanocrystals
… of dye molecules on the NP surface. To this end, colloidal nanocrystals (NCs), which are crystalline particles dispersed in a solvent medium, are used. These colloidal NCs present a more homogenous environment for dye-binding, and this reduced heterogeneity can make it easier to elucidate the …
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On the origin of photons : understanding excitons and multiexcitons in colloidal semiconductor nanocrystals
… studies of exciton and multiexciton dynamics in colloidal semiconductor nanocrystals. I concentrated primarily on the development of correlation spectroscopies for the measurement of the statistics and dynamics of multiexciton emission. Under most conditions, the emission properties of …
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