Polyoxometalates are a rapidly growing class of discrete metal oxide clusters with a wide range of applications including functional materials. These anionic clusters of the group V and VI transition metals are inexpensive and non-toxic. Within group V polyoxometalates, niobium and tantalum chemistry has been underdeveloped owing to their unique...
The subject of this PhD thesis is part of a research domain of great present interest in new semiconductor materials for photovoltaic and thermoelectric applications. This domain contains the elaboration and the study of both Cu-based chalcogenides bulk and thin-film samples, driven by materials design principles.
One of the most...
A scalable synthesis of the "flat" tridecameric inorganic cluster [Al₁₃(μ₃-OH)₆(μ-OH)₁₈(H₂O)₂₄]¹⁵⁺ has been realized by treating an aqueous aluminum nitrate solution with zinc-metal powder at room temperature. Single crystals and polycrystalline samples are readily obtained in yields exceeding 55% relative to the starting reagent Al(NO₃)₃. Products have been characterized by X-ray...
Piezoelectric materials have been widely used in electromechanical actuators, sensors, and ultrasonic transducers. Among these materials, lead zirconate titanate Pb(Zr[subscript 1‐x]Ti[subscript x])O₃ (PZT) has been primarily investigated due to its excellent piezoelectric properties. However, environmental concerns due to the toxicity of PbO have led to investigations into alternative materials systems....
The chemistry of hafnium oxide based and materials are described in the context of ion exchange and lithography. HafSOx, represented by the composition HfO₂₋[subscript x](SO₄)x, is described to possess a significant capacity towards ion exchange in acidic and basic solutions, enabling films of HafSOx to be cleanly and readily be...
Solid-state amorphous materials show amazing promise in thin-film electronics. The interface-to-bulk ratio of thin films makes interfacial chemistries of these systems of utmost importance. Thin films of amorphous metals, dielectrics and semiconductors have novel chemistries that are not only based upon their elemental constituent makeup, but also based upon the...
This thesis presents basic studies, including structural, optical and transport measurements, on novel chalcogenide powders and single crystals. BiCuOSe crystals have been synthesized for the first time. The crystal structure of BiCuOSe has been refined and the optical band gap has been measured to be 0.83eV. Crystal structure refinements of...
Novel donor-type graphite intercalation compounds (GICs) containing tetra-n-alkylammonium (TAA) cations have been synthesized by using both ion-exchange and electrochemical methods. Structural and compositional data of the resulting TAA-GICs are investigated by using powder X-ray diffraction (PXRD), one-dimensional electron density calculations, thermogravimetric and elemental analyses, and capillary zone electrophoresis (CZE). A...
More than 30 members of the diverse amphidinolide family of biologically active macrolides have been isolated over last three decades. From this family, amphidinolides C and F stand among the most complex and densely functionalized affiliates. Recently, we have accomplished the first total synthesis of amphidinolide F. The all-carbon framework...
Much recent research has focused on the development lead-free perovskite piezoelectrics as environmentally compatible alternatives to lead zirconate titanate (PZT). Two main categories of lead free perovskite piezoelectric ceramic systems were investigated as potential replacements to lead zirconate titanate (PZT) for actuator devices. First, solid solutions based on Li, Ta,...