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Helen Pleydell-Bouverie, the Countess of Radnor, who conducted an amateur ladies' orchestra from 1881 until 1896, was a critical early pioneer in the development of female orchestral performance in England. Lady Radnor's orchestra was widely praised, and she herself was highly regarded by British royalty, artistic elite, and lower-class audiences alike. While her probable status as the first British woman to regularly and publicly conduct an orchestra merits recognition on its own, her work is of yet further interest as an important step in the advancement of women musicians from the salon to the professional concert hall. In a time when professional musicianship was not accessible to upper-class women, Lady Radnor became a significant influence in musical culture through patronage, pedagogy, entrepreneurship, and especially philanthropy. Indeed, charitable activity was the main structure that enabled aristocratic women to have public performance careers. Her example shows that the professional female conductors who emerged in the twentieth century were not rogue anomalies, but rather built upon the cultural foundation laid in part by the work of aristocratic amateurs.

Transparent conducting oxides (TCOs) have attracted extensive attention for decades due to their remarkable applications in optoelectronic devices. The development of functional nanostructured TCOs with unique properties, and an expansion of their functionalities are therefore research directions of significant current interest. Among TCOs, In2O3 is widely applied because of its high charge carrier concentration and mobility, as well as the ease with which it can be deposited as a thin film. The important role of surfaces in tuning properties in materials shows the importance of studying nanostructured materials with high surface areas. In this thesis I examined the synthesis of phase-controlled In2O3 nanocrystals (NCs) and showed the effect of doping and composition on the materials properties. Owing to the relevance of size, structure, and composition for manipulating properties of nanomaterials, synthesis of well-defined nanocrystals of pure and doped In2O3 has been of considerable interest for fundamental studies as well as for technological applications. Phase controlled synthesis of colloidal In2O3 NCs was achieved via a size-structure correlation. The study of the morphological and phase transformations of In2O3 NCs during their growth in solution implies that corundum (rh-In2O3) is a transient structure in the formation of cubic bixbyite (bcc-In2O3) phase. The formation of NCs smaller than 5 nm leads to the spontaneous stabilization of metastable phases owing to the surface energy and/or surface stress contributions, both of which are dependent on size. The growth beyond the critical size lowers the potential energy barrier height and causes the nanocrystal phase transformation. In addition, phase transformation of colloidal In2O3 NCs in the temperature range of 210-260 ˚C during their synthesis in solution was studied using a combination of structural and spectroscopic methods, including X-ray diffraction (XRD), transmission electron microscopy (TEM) and extended X-ray absorption fine structure (EXAFS) spectroscopy, and analyzed data using Johnson-Mehl-Avrami-Erofeyev-Kholmogorov (JMAEK) and interface nucleation models. The phase transformation occurs via nucleation of bcc-In2O3 phase at the interface between contacting rh-In2O3 NCs, and propagates rapidly throughout the NC volume. In situ high temperature XRD patterns collected during nonisothermal treatment of In2O3 NCs reveal that phase transformation of smaller NCs occurs at a faster rate and lower temperature, which is associated with the higher packing density and contact formation probability of smaller nanoparticles. Owing to the fact that NC surfaces and interfaces play a key role in phase transformation, their control through the synthesis conditions and reaction kinetics is an effective route to manipulating NC structure and properties. Although, doping semiconductor NCs is crucial for enhancing and manipulating their functional properties, the doping mechanism and the effects of dopants on the nanocrystal growth and structure are not well understood. We show that dopant adsorption to the surfaces of colloidal In2O3 NCs during incorporation inhibit NC growth and leads to the formation of metastable rh-In2O3 for nanocrystals smaller than ca. 5 nm. Direct comparison between Cr3+ and Mn3+ dopants indicates that the nanocrystal structure directly determines the dopant incorporation limits and the dopant electronic structure, and can be predicted and controlled. These results enable a new approach to designing multifunctional nanostructures and understanding the early stages of crystal growth in the presence of impurities. Nanocrystalline films fabricated from colloidal Cr3+- and Mn3+- doped In2O3 nanocrystals exhibit strong ferromagnetic ordering up to room temperature. The absence of ferromagnetism in the free standing transition metal (TM)-doped In2O3 NCs and appearance of ferromagnetism only in TM:In2O3 films prepared from colloidal NCs, are attributed to the formation of extended structural defects, proposed to be oxygen vacancies at the NC interfaces. In fact, in TM:In2O3 NCs with high surface to volume ratios, more oxygen vacancies are present at the surface of NCs and networking of NCs in the prepared film causes an increase in grain-boundary defects at the interfaces. A comparative study of magnetic circular dichroism (MCD) spectra of Cr3+-doped bcc-In2O3 and Cr3+-doped rh-In2O3 revealed that Cr3+ ions distinctly occupy different symmetry sites in corundum and bixbyite crystal structure of In2O3. In fact, a change in the crystal structure of In2O3 from bixbyite to corundum changes the electronic configuration of Cr3+. By manipulating the NC composition and structure in solution we applied a one-step synthesis of ternary gallium indium oxide (GIO) nanocrystals with variable crystal structures. The structures and sizes of GIO NCs can be simultaneously controlled, owing to the difference in the growth kinetics of In2O3 and Ga2O3 NCs, and the polymorphic nature of both materials. These dependences, induced by the interactions between specific defect sites acting as electron donors and acceptors, were used to achieve broad emission tunability in the visible spectral range at room temperature. The nature of the photoluminescence is identified as donor -acceptor pair (DAP) recombination and changes with increasing indium content owing to the changes in the energy states of, and interactions between, donors and acceptors. Structural analysis of GIO nanocrystals by extended X-ray absorption fine structure spectroscopy reveals that In3+ occupies only octahedral, rather than tetrahedral, sites in the spinel-type γ-Ga2O3 nanocrystal host lattice, until reaching the substitutional incorporation limit of ca. 25%. The emission decay dynamics is also strongly influenced by the nanocrystal structure and composition.

Thesis (Ph. D.)--University of North Texas, 2001. / Includes bibliographical references (p. 303-307).

Luminescent lanthanide complexes have been widely studied for various biotechnology and materials science uses, however, the application of these luminescent systems in metallopolymers has been relatively limited, especially when compared to those incorporating transition metal complexes. The unique and interesting photophysical properties of lanthanide complexes (i.e., high color purity and long radiative lifetimes) make these systems ideal for the development of luminescent metallopolymers, which are a unique class of hybrid materials that synthetically incorporate metal centers into organic polymers, thereby taking advantage of the beneficial properties of both traditional inorganic (i.e., catalysis, optics, electronics) and organic (i.e., easy to process, flexible, low weight) materials. A new class of lanthanide complexes exhibiting metal-based visible and near-IR photoluminescence has been designed, synthesized and fully characterized by melting point, ESI-MS, elemental analysis and single crystal and powder X-ray diffraction (when possible). The photophysical properties of these luminescent monomer complexes were studied in solution and the solid state, with the emission spectra displaying the characteristic line-like emission peaks of the trivalent lanthanide ions. This indicates efficient energy transfer from ligand centered excited states to the emissive excited states of the lanthanides. The monomer complexes have been electropolymerized, resulting in conducting metallopolymers that display metal-based photoluminescence. Because these hybrid materials retain the desirable properties of both inorganic semiconductors and organic polymers, such as near metallic electrical conductivity, ease of processing, flexibility and light weight, they are promising for applications in solid-state lighting. / text

Sunlight is sustainable, clean and readily available energy source, which is one of the potential alternatives to the traditional energy sources. Recently, the organic photovoltaics (OPVs), in particular polymer solar cells (PSCs), have attracted increasing attention owing to their outstanding properties such as low cost, lightweight, flexible, allowing vacuum-free fabrication process and thin-film architecture. These advantageous material and manufacturing features of PSCs provide the opportunities for many novel applications. However, the lower power conversion efficiencies (PCEs) of PSCs compared to inorganic solar cells hinder their competition in the marketplace. This thesis covers the basic principles of the PSC, strategies for enhancing PCEs as well as the recent development of PSCs. The importance of the source materials has been also demonstrated and discussed. Due to a large number of possibilities, limited resources and time, it is not feasible to do all the work experimentally. Therefore, for continuing advance development of PSCs, the device performance should be modeled as a function of material parameters, which requires the knowledge of material properties, in particular the complex index of refraction N= n - ik. Accurate determination of the optical functions of the active layers and light trapping layers commonly used in PSCs by using the spectroscopic ellipsometry (SE) has been demonstrated. In order to acquire reliable solutions, the methodology including multiple sample analysis, combinations of different measurement techniques, selection of models, the rigorous fitting procedures and the independent verification have been proposed. The obtained information can be used in the simulation to optimize device architectures, model device performance as well as characterize novel materials. / published_or_final_version / Physics / Doctoral / Doctor of Philosophy

The work presented in this thesis provides a new route to a colloidal form of polyaniline, which uses colloidal silica as a dispersant. We obtained stable colloidal dispersions of polyaniline-silica composite particles with a 'raspberry' morphology. Compressed pellets of these particles exhibit solid-state conductivities of 1O-!_10-2 S crrr l, which is approximately 1-2 orders of magnitude lower than that of polyaniline bulk powder. This novel colloidal form of polyaniline has significantly improved processability compared to conventionally synthesised polyaniline. The synthesis and chemical characterisations are presented for various polyaniline-silica colloidal nanocomposites. The quantity of polyaniline incorporated into the nanocomposite particles can be controlled by varying the diameter of the silica dispersant, approximately 20% and 60 % polyaniline content being obtained using 120 nm and 10 nm diameter silica respectively. The average particle size ranges of nanocomposites was found to be 150 to 700 nm and 330 to 560 nm, as determined by transmission electron microscopy (TEM) and disc centrifuge photosedimentometry (DCP) respectively. The nanomorphology and surface composition of the polyanilinesilica particles were determined by small angle X-ray scattering (SAXS) and X-ray photoelectron spectroscopy (XPS) respectively. The average inter-particle separation distance of the silica particles within the polyaniline-silica raspberries was determined by SAXS to be 4 nm, a dimension equivalent to molecular polyaniline. The XPS data suggests that the surface of the particles is silica rich, this is consistant with their long term colloidal stability in 1.2 mole dm-3 HCl. The kinetics of polymerisation was studied using 1H NMR spectroscopy to monitor the disappearance of aniline monomer. Polymerisation rates during the synthesis of polyaniline-silica nanocomposites were appreciably faster than the corresponding precipitation polymerisations carried out in the absence of silica dispersants, due primarily to an increase in the second auto-catalytic step of the reaction. Rate constants were determined for both these types of synthesis; the values obtained for the precipitation polymerisations were in reasonably good agreement with literature values.

Petite symphonie / Charles Gounod -- Little threepenny music for wind ensemble / Kurt Weill / text