Recent discoveries of kimberlites in North America have revealed that different processes are involved in the generation of kimberlite magma. A multi-disciplinary approach combining mineralogical, petrological, geochemical, and geochronological methods is used to classify the kimberlites, investigate possible sources of magma and evaluate current tectonic models proposed for the generation of kimberlite magma. The two main study areas are 1) the diamond-poor Churchill kimberlite field (Nunavut); and 2) the highly diamondiferous Lac de Gras kimberlite field (NWT). The Attawapiskat kimberlite field, the Kirkland Lake kimberlite field and the Timiskaming kimberlite field (Ontario) are also included in this study. The 55-56 Ma Diavik kimberlite cluster (NWT) have been classified as resedimented volcaniclastic > olivine-bearing volcaniclastic > mud-bearing volcaniclastic > macrocrystic oxide-bearing hypabyssal kimberlite > calcite oxide hypabyssal kimberlite > tuffisitic kimberlite breccia. Geochemical features of Diavik kimberlites include: 1) LREE enrichment, 2) large intra-field range in REE content, and 3) highly diamondiferous kimberlites at Diavik with primitive geochemical signatures. The Churchill kimberlites are classified as sparsely macrocrystic, oxide-rich calcite evolved hypabyssal kimberlite and macrocrystic oxide-rich monticellite phlogopite hypabyssal kimberlite. Electron microprobe analyses of olivine, phlogopite, spinel and perovskite support this petrographical classification. Twenty-seven precise U-Pb perovskite and Rb-Sr phlogopite emplacement ages indicate that magmatism spans ~45 million years (225-170 Ma). The crystallization ages and the Sr and Nd isotopic compositions of groundmass perovskite from a well-established, SE-trending Triassic-Jurassic corridor of kimberlite magmatism in Eastern North America (ENA) were determined to investigate the origin of this magmatism. The Sr isotopic results indicate that the Churchill (0.7032-0.7036) and Attawapiskat kimberlites (0.7049-0.7042) have unique isotopic compositions, while Kirkland Lake/Timiskaming perovskite have a larger range of 87Sr/86Sr ratios. This implies the derivation of kimberlite magma from two distinct sources in the mantle, a depleted MORB mantle source and a kimberlite magma with a Bulk Silicate Earth signature. The pattern of increasing 87Sr/86Srinitial with younging of kimberlite magmatism along the ~2000 km corridor of continuous Triassic/Jurassic magmatism could be explained from either a single or multiple hotspot track(s), responsible for the addition of heat required to generate small volume mantle melting of a kimberlite source.

Thesis (Ph. D.)--University of Washington, 2008. / Vita. Includes bibliographical references (leaves 111-119).

Thesis (M.Phil.) - University of St Andrews, September 2007.

Thesis (Ph.D.)--University of Delaware, 2008. / Principal faculty advisor: Douglas J. Buttrey, Dept. of Chemical Engineering. Includes bibliographical references.

Thesis (Ph.D.)--Materials Science and Engineering, Georgia Institute of Technology, 2008. / Committee Chair: Speyer, Robert; Committee Member: Gerhardt, Rosario; Committee Member: Liu, Meilin; Committee Member: Lynch, Christopher; Committee Member: Wilkinson, Angus

Thesis (Ph. D.)--University of Washington, 2004. / Vita. Includes bibliographical references (leaves 194-209).

Thesis (Ph.D.) - University of St Andrews, March 2008. / Restricted until 14th March 2009.

Thesis (Ph.D.) - University of St Andrews, January 2008.

Thesis (Ph.D.) -- McMaster University, 2001. / Includes bibliographical references. Also available via World Wide Web.

Over the last 4 years, perovskite solar cells emerged as an attractive, highly efficient, and low-cost alternative to established, conventional photovoltaic technologies. The power conversion efficiency of these devices recorded an unprecedented rise, currently exceeding certified values of 20%. This thesis covers a number of technological advancements which lead to improved photovoltaic performance, as well as vital insight into some more fundamental aspects of the perovskite device operation. The focus of this body of work is primarily directed towards the electric contact in the PV stack which is responsible for electron collection. The motivation of the study presented here is given in Chapter 1, and includes a brief summary of the current energy landscape. Chapter 2 introduces the theoretical background of photovoltaic technology, starting from the basics of semiconductor physics, through to the principles of solar cell operation, as well as some characteristic properties of the perovskite materials. Details of the experimental methods used in this study are reported in Chapter 3. Chapter 4 reports the development of a low temperature process (sub-150 °C) for the manufacture of perovskite solar cells. Dispersions of pre-synthesised, highly crystalline TiO2 nanoparticles were used as an electron selective contact, which eliminated the high temperature sintering step. Chapters 5, 6 and 7, report the interface modification of an n-type contact, resulting in a substantially improved device operation and suppression of hysteresis phenomenon which is characteristic of perovskite photovoltaics. Fullerene-based materials have been found to make excellent electronic contact with halide perovskite materials, and are shown to be far superior to commonly used metal oxides. The facilitated electron collection allows enhancements in the photovoltaic performance of these devices. Furthermore, the organic layers used in this study can be processed at low temperatures. Finally, the development of transparent conductive electrodes based on silver nanowires is presented in Chapter 8. The fabricated electrodes exhibit low sheet resistance, high degree of transparency, and can be processed at low temperatures, allowing them to be compatible with processing on flexible substrates and multi-junction architectures. The application of silver nanowires in different perovskite solar cell architectures is also reported.