As the pursuit for higher performance and lower cost photovoltaics, and for new applications of optoelectronic devices moves beyond crystalline silicon, there are many unique opportunities for materials research into hybrid organic-inorganic, and organic semiconductors. This dissertation focuses on both hybrid organic-inorganic materials and organic materials for optoelectronic applications. In...
Ultrafine particles are often used as lubricant additives because they can enter tribological contacts to reduce friction and protect surfaces from wear. They tend to be more stable than molecular additives under high thermal and mechanical stresses during rubbing. However, in lubricant oil, ultrafine particles tend to aggregate together to...
Semiconductor nanocrystals possess unique photophysical properties that make them desirable for many optoelectronic applications such as photovoltaics, LEDs, and quantum computing. When the size of a semiconductor is reduced to below the excitonic Bohr radius of the material, its carriers becomes quantum confined resulting in drastic changes to optical, electronic,...
Early-stage oxidation and corrosion mechanisms of CoCrMo and NiCrMo alloys can be analyzed on the nanoscale by transmission electron microscopy. Both alloys are attractive for a broad array of applications such gas turbines and aircraft engine components as they are known for their excellent corrosion resistance and mechanical properties at...
The halide perovskites AMX3 (A = large cation, B = Sn or Pb, and X = halide) have been the subject of intense investigation due to their outstanding optical and electronic properties, which have enabled high solar cell efficiencies thanks to a beneficial electronic structure and long charge carrier lifetimes....
How molecular chirality manifests at the nano- to macroscale has been a scientific puzzle since Louis Pasteur discovered biochirality. In general, amphiphilic molecules can organize into a variety of assembly shapes including micelles, spherical vesicles, cylindrical micelles, and planar bilayers. However, when such amphiphilic molecules are chiral, helical ribbons, helicoidal...
This thesis explores the potential of two-dimensional (2D) or van der Waals (vdW) materials for printed optoelectronic devices. The research focuses on the development of processing, imaging, and modeling of materials and thin-film devices to optimize performance and introduce novel properties. A gate-dependent resistor network model is presented that establishes...
The three-dimensional (3D) nanoscale structure of III-As nanowires is correlated with optical and electronic property measurements to deconvolve the contributions of strain, composition, and crystal structure to characteristics of interest for future electronic and optoelectronic devices. Multiple advanced two-dimensional (2D) and 3D characterization techniques are employed such as atom probe...
Advancements in the understanding and synthesis of transition metal compounds have allowed materials engineers to design functional materials with a range of properties, such as ferroelectricity, non-linear optical activity, colossal magnetoresistance, and superconductivity. Conventional routes to tune and design functional materials includes chemical cation substitution and heterostructuring of oxide thin...
Rationally assembled nanostructures exhibit distinct physical and chemical properties beyond their individual units. The development of nanofabrication tools enables precise structural defining of nanomaterials scalable to large areas. This dissertation focuses on plasmonic nanoparticle arrays that show unique diffractive coupling with lattice spacings engineered close to the wavelength of light....
Scalable processing of well-defined interfaces is key not only for wider application of two-dimensional (2D) materials in technology but also for improved fundamental understanding. Atomic layer deposition has useful characteristics, especially self-limited growth at low temperatures, that make it well suited for the production of uniform interfaces. Related processes, such...
There is considerable technical interest in the improvement of battery technology, as it would allow for the enhancement and realization of many different applications, including the continued miniaturization of portable computational devices, plug-in electric vehicles, and intermittent power storage. Lithium metal represents a theoretical limit on the anode energy density...
Elemental powder blends are an emerging alternative to prealloyed powders for high-throughput alloy design via additive manufacturing techniques due to their flexibility, low cost, and ease of customization. This dissertation investigates elemental alloying elements (Sc and Zr) which are high-melting and highly reactive, unlike previous work which focused on more...
As demonstrated by efforts in graphene commercialization, scalable synthesis and high-quality material availability are primary limiting factors for the realization of technologies based on two-dimensional (2D) materials. Thus, in considering the fate of emergent 2D materials such as the metal chalcogenides, the challenge of scalable synthesis is a highly relevant...
Nanotechnology research broadly encompasses the exploration of the unique chemical,optical, electronic, or biological properties of materials with dimensions < 1 µm. Inorganic
nanoparticles are one such class of materials, with properties that are exceptionally sensitive to
particle size and structure. This is especially evident in the field of heterogeneous chemical...
Soft materials in nature are formed through programmed self-assembly of biomolecules to create complex architectures and optimized physical properties. It is therefore a key challenge in biomaterials science and engineering to understand the principles that govern the structure and properties of such materials, and the interactions between their different components....
Transport along and across the grain boundaries of solid-state electrolytes has implications for a broad range of materials and in an equally broad range of technologies. Over the past 2-3 decades, a substantial body of literature has been developed to explain grain boundary transport properties within the context of space...
Nanoparticle synthesis is capable of producing particles with any combination of structure, chemistry, size, shape, and surface. All of the different combinations of these physical properties can produce nanoparticles with almost countless materials properties suited for many applications. Given this interest in using nanoparticles in so many different fields, including...
In the late 2000’s, scientific studies in cultural heritage saw a great advancement in macro X-ray fluorescence (XRF) imaging of paintings. These images are used to generate elemental distribution maps, which aid in identifying chemical elements and paint pig- ments as well as their locations throughout the layers of the...
One of the central challenges in solid-state chemistry is synthetic control over structure. Owing to limited reactivity of Pb with transition metals at ambient pressure and high temperature as well as the variety of properties that emerge from the few known binary transition-metal–Pb compounds, this research focuses on accessing and...