Solid oxide fuel cells (SOFCs), renowned for their high electrical generation efficiency with low pollutant production, are promising for reducing global energy and environmental concerns. However, there are major barriers for SOFC commercialization. A primary challenge is reducing the capital cost of SOFC power plants to levels that can compete...
Biomorphic silicon carbide (bioSiC) is a novel porous ceramic material derived directly from wood precursors. This material is fabricated by pyrolysis of a natural wood precursor in an inert atmosphere leaving an amorphous carbon scaffold. The amorphous carbon is infiltrated with molten Si in vacuum at elevated temperature, which reacts...
The electronic transport and magnetoresistive properties of the ferromagnetic semiconductor In1-xMnxAs were investigated in order to determine the nature of the transport and ferromagnetism in the films. p-InMnAs/n-InAs and metal/oxide/InMnAs heterojunctions were fabricated and characterized to elucidate the transport and magnetoresistance mechanisms at these technologically important interfaces.
The electronic transport...
The transport properties of mayenite-based materials, Ca12Al14O33, were investigated. Systems studied included H-doped/ UV-irradiated Ca12Al14O33, Ca(12-x)MgxAl14O33 (x = 0.1, 0.3, 0.5, 0.8, 1) and Ca12Al(14-x)SixO(33+x/2) (x = 1, 2, 3, 4). The as-prepared Ca12Al14O33 exhibited a room temperature electronic conductivity on the order of 10^-10 S/cm, and a high temperature...
Graphene offers promising opportunities for applications in printed and flexible electronic devices due to its high electrical and thermal conductivity, mechanical flexibility and strength, and chemical and environmental stability. However, scalable production and processing of graphene presents a critical technological challenge preventing the application of graphene for flexible electronic interconnects,...
In today's rapidly changing world, there is constant demand for the development of new, high performance materials. Fire resistant steels can provide greater safety in the event of a building fire, creep resistant stainless steels can allow for higher power plant efficiency, and cobalt based superalloys have potential for use...
Accurate thermodynamic databases are the foundation of predictive microstructure and property models. An initial assessment of the commercially available Thermo-Calc TCAL2 database and the proprietary aluminum database of QuesTek demonstrated a large degree of deviation with respect to equilibrium precipitate phase prediction in the compositional region of interest when compared...
Significant deviations in the glass transition temperature (Tg) of nanoconfined polymer films from the bulk have been studied for over twenty years with the focus on high molecular weight (MW), linear polymers. This thesis explores low MW polymers, which represent an important class of materials widely used as coatings, detergents,...
Metal and bimetallic nanoparticles are of interest and are widely used in various applications because of their unique optical, electronic, and catalytic properties, which differ from those of their bulk counterparts. Better understanding of the thermodynamic and kinetic properties of nanoparticles and their underlying growth mechanisms can serve as a...
Increasing energy demand due to rapid growth in population and industrialization along with environmental crisis has led to the search for cheap, environmentally friendly, and nontoxic methods for generation of energy. However, most alternative energy sources such as photovoltaic, biofuels, hydraulic power, wind power, and geothermal energy, are characterized by...
The impacts of many important technologies are limited by the availability of better-performing materials. One factor limiting the ability of engineers to develop better materials is the speed at which they can search through possible formulations and processing schemes. Recently, machine learning algorithms have emerged as a possible route to...
Nano-structured mixed ionic and electronic conducting (MIEC) materials have garnered intense interest in electrode development for solid oxide fuel cells due to their high surface areas which allow for effective catalytic activity and low polarization resistances. In particular, composite solid oxide fuel cell (SOFC) cathodes consisting of ionic conducting scaffolds...
Growing energy and climate concerns in the United States and across the world demand improvements in energy efficiency, conservation, and renewability. Solid oxide fuel cells (SOFCs) are highly efficient devices that electrochemically convert the chemical energy of a fuel to electricity. These devices can operate on natural gas as a...
Organic photovoltaic (OPV) solar cells aim to provide efficient, flexible and lightweight photovoltaics (PV) with simple processing and low-cost. Advances in device optimization, structural and molecular design, as well as mechanistic understanding have helped increase device efficiency and performance. Within the framework of active layer optimization, systematically improving bulk heterojunction...
Worldwide, governments are beginning to take action to reduce anthropogenic CO2 emissions in order to mitigate the extent of global climate change. The largest fraction of global CO2 emission comes from electrical power generation, which is rapidly being converted to wind and solar installations. The intermittent nature of renewable resources...
The microwave, optical, and electro-optic properties of epitaxial barium titanate thin films grown on (100) MgO substrates and photonic crystal electro-optic modulators fabricated on these films were investigated to demonstrate the applicability of these devices for telecommunication and data networks. The electrical and electro-optical properties were characterized up to modulation...