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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Structural and synthetic studies of compounds containing tin and the noble metals

Machell, Jonathan Charles January 1990 (has links)
No description available.
2

TETRANUCLEAR CU(I) CLUSTERS WITH TUNABLE EMISSIONS BASED ON REMOTE STERIC CONTROL

Benjamin M Washer (14213087) 05 December 2022 (has links)
<p>Solid-state (SS) luminescent materials are an important class of materials in a myriad of technological applications including light-emitting devices (LEDs) and displays, SS lasers, sensors, imaging agents, etc. Unfortunately, the design of efficient SS emitters is often plagued by sensitivity to environment/matrix (e.g. aggregation-induced quenching, AIQ), competing non-radiative relaxation pathways, and complicated emission mechanisms that are difficult to systematically study and tune. Copper-based systems have been proven to be good candidates for SS emissive materials due to their low-cost, high synthetic variation and well-defined features. Examples of copper-cluster systems, specifically, have been shown to be highly stable, exhibit high photoluminescent quantum yields (ΦPL), and are often relatively insensitive to environmental changes. However, many of these systems are complicated in nature, and often evoke additional relaxation pathways. To mitigate these issues, tetranuclear Cu(I)-pyrazolate complexes have been made which exhibit high ΦPL, matrix insensitivity and proceed through one major radiative emission pathway: cluster-centered based phosphorescence (3CC). The pyrazoles are highly tunable, and by increasing the size of the ligand substituents (H, F, Cl/Me/Br), a rigidochromic effect is observed, causing a significant blue-shift in their photoluminescence, making these viable materials for organic LEDs (OLEDs), especially in the deep-blue region. Furthermore, by increasing the chain length of the ligand substituent (e.g., Me → Et), another material which exhibits stimuli-responsive luminochromism in response to solvent vapor or heat can be achieved. This material exhibits blue ↔ green rigidochromic luminescence in response to stimuli via isomerization of the ethyl units from exo ↔ endo resulting in additional steric effects that effectively prevent rigidification of the Cu4 cluster. This additional phenomenon opens the door for further exploration of Cu(I)-pyrazolate complexes for stimuli-responsive luminescent materials (SRLMs) applications.</p>
3

THE ROLE OF ION TRANSFER IN NANODROPLET-MEDIATED ELECTRODEPOSITION

Joshua Reyes Morales (16925016) 05 September 2023 (has links)
<p dir="ltr">Nanoparticles have seen immense development in the past several decades due to their intriguing physicochemical properties. The modern chemist is interested not only in methods of synthesizing nanoparticles with tunable properties but also in the chemistry that nanoparticles can drive. While several methods exist to synthesize nanoparticles, it is often advantageous to put nanoparticles on a variety of conductive substrates for multiple applications (such as energy storage and conversion). Despite enjoying over 200 years of development, the electrodeposition of nanoparticles suffers from a lack of control over nanoparticle size and morphology. Understanding that structure-function studies are imperative to understand the chemistry of nanoparticles, new methods are necessary to electrodeposit a variety of nanoparticles with control over macro-morphology but also microstructure. When a nanodroplet full of a metal salt precursor is incident on the electrode biased sufficiently negative to drive electroplating, nanoparticles form at a shocking rate (on the order of microseconds to milliseconds). We start with the general nuts-and-bolts of the experiment (nanodroplet formation and methods for electrodeposition). The deposition of new nanomaterials often requires one to develop new methods of measurement, and we detail new measurement tools for quantifying nanoparticle porosity and nanopore tortuosity within single nanodroplets. Owing to the small size of the nanodroplets and fast mass transfer, the use of nanodroplets also allows the electrodeposition of high entropy alloy nanoparticles at room temperature. Electrodeposition in aqueous nanodroplets can also be combined with stochastic electrochemistry for a variety of interesting studies. We detail the quantification of the growth kinetics of single nanoparticles in single aqueous nanodroplets. Nanodroplets can also be used as tiny reactors to trap only a few molecules, and the reactivity of those molecules can be electrochemically probed and evaluated with time. Overall, this burgeoning synthetic tool is providing unexpected avenues of tunability of metal nanoparticles on conductive substrates. Moreover, there is little understanding of how ion transfer can affect the fundamental of nanoparticle synthesis with nanodroplet-mediated electrodeposition. This thesis details different experiments performed to study the role of ion transfer during the nucleation and growth of nanoparticles.</p>

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