The continuing increase in atmospheric CO2 to concentrations exceeding 400 ppm has attracted considerable attention from both scientists and policymakers. Industrial fossil fuel consumption generates a significant amount of CO2 emissions, and in particular, energy-intensive molecular separations that require thermal processes, such as distillation, drying, or evaporation, are responsible for...
Increasing industrialization and the resulting negative environmental impacts highlight the need to develop alternative renewable energy sources. The Sun is a massive source and organic solar cells are a growing field of study. As new materials are synthesized, the efficiencies of organic solar cells continue to grow, but without an...
Complex microstructures are ubiquitous in nature. The evolution of these microstructures alters their morphology and topology and thus very often dictates material properties, such as mechanical, electronic, thermal, and magnetic properties. Thus, in order to predict and control material properties, it is essential to have robust and efficient techniques to...
Atomistic methods offer a powerful set of tools in the study of materials systems, as they allow materials scientists to ask questions with a high degree of specificity. They are well suited for studying and designing energy materials, critical due to the climate crisis, in part due to their ability...
One of the grand challenges in materials chemistry and nanochemistry is the development of functional materials through ordered, hierarchical structures using synthetic building blocks. Nature has done this through evolution of molecular components such as nucleic acids, saccharides, lipids, amino acids, and inorganic crystals. The precise spatial positioning of these...
This thesis centers around the development and application of novel high throughput lithography tools. These advances help: 1) establish the field of nanocombinatorics, where massive libraries (termed megalibraries) of materials can be prepared in a positionally encoded manner and then screened for functional activity, and 2) advance stereolithographic 3D printing...
The effect of interfaces in solids on the overall charge transport properties has become a topic of growing importance for energy materials such as thermoelectrics. In some polycrystalline thermoelectric materials, the performance near room temperature is significantly limited due to thermally-activated electrical conductivity near room-temperature, which can be attributed to...
Functional electronic materials are difficult to design due to the complex interplay among chemistry, atomic structure, and electrical properties. This dilemma is further amplified in transition metal compounds which can defy the band-theory description of non-correlated electrons. Exploring the vast possible design space completely with experiments or first-principles simulations is...
Heteroanionic materials are a class of materials of interest for their unique and tunable electronic, ionic, thermal, and optical properties, which are distinct from their homoanionic counterparts due to their multi-anionic nature. Oxynitrides, a type of heteroanionic material, are useful catalysts due to the effect of mixing oxygen and nitrogen...
Given directives such as the UN Global Goals targeting sustainable development, the research presented herein makes but a small contribution to the advancement of alternative energy technologies. Nevertheless, the present work was largely motivated to address specific points of intrigue within the thermoelectrics community. The general principles demonstrated, however, may...
Biomaterials have immense potential for studying fundamental biological processes and developing therapies to help regenerate or replace the structure and function of injured tissues. In order to accomplish this, they need to be designed to mimic the structure and function of Nature’s most important material, the extracellular matrix (ECM) surrounding...
Two-dimensional (2D) hybrid halide perovskites have been the response to their exciting but woefully unstable 3D counterparts. These 2D perovskites have been shown to have respectable stabilities as photovoltaic absorbers, yet they lag behind the 3D perovskites in terms of efficiency. With the need to catch up to the efficiencies...
The dissertation systematically delineates the mechanically-guided deterministic assembly of three-dimensional (3D) mesostructures by compressive buckling, covering topics from mechanics concepts, design and analysis, fabrication techniques, to application opportunities. The development of approaches to form complex 3D functional mesostructures in advanced materials is a topic of broad interest, thanks to the...
Directional freeze-casting is a porous materials fabrication technique that is used to create materials with complex, three-dimensional pore structures. Particle suspensions are solidified under a thermal gradient, promoting anisotropic growth of dendrites and incorporation of particles within interdendritic space. A fully-solidified directional freeze-cast structure is composed of dendrites that are...
Biomineralization relies on the regulation of localized environments to control how minerals are formed. Through the use of confinement and specific additives, the organism is able to change the energy landscape of nucleation and growth to build single crystals with unusual morphologies. In order to better understand the environments in...
A framework is developed that models point defect diffusion and interaction with pre-existing microstructures during irradiation, including defect-defect interactions and defect sinks. This framework uses a modified diffusion potential that includes not only defect concentration, but also intrinsic stresses from the pre-existing microstructure. Various microstructures are studied in {Fe} by...
Dendritic microstructures form during the solidification of a variety of metal parts, from traditionally cast engine blocks to 3D-printed specialty tooling. These dendrites can evolve through growth, coarsening, fragmentation, and the formation of a Columnar-to-Equiaxed Transition (CET), which all can greatly affect material properties. However, the basic science behind these...
The highly flexible nature of 2D materials has led to them becoming fundamental building blocks for achieving novel device physics and potential breakthroughs in practical technologies. 2D layers can be interfaced in a wide array of methods with themselves, other 2D layered materials, or materials of entirely different type or...
Non-planar and curved architectures of otherwise flat 2D materials present an important paradigm for nanoscale analysis and design of emergent material properties. Atomically-thin transition metal dichalcogenides (TMDs) have emerged at the forefront of the 2D materials field in recent years largely due to their attractive and tunable chemical, optical, and...
Herein, we present an overview of our studies of the morphology, dynamics, and formation of heterogeneous soft matter systems via the emerging technique of liquid phase transmission electron microscopy (LPTEM). This particular subset of materials, more commonly referred to as emulsions, is tremendously commercially and biologically relevant, encompassing applications in...
Interfacial science brings together diverse areas of interest such as electronic materials, quantum materials, bio-membranes and catalysts. In-situ X-ray characterization techniques can be used to understand the assembly of atoms, molecules and supported nanoparticles at interfaces in complex environments. This thesis work focuses on the use of various X-ray characterization...
An extensive set of functional electronic properties depends on the electronic structure. These properties are directly connected to the reciprocal-space representation of electronic structure. However, there is a complementary, real-space perspective that is described by combinations of atomic orbitals. Atomic orbitals are the components of electronic structures, analogous to how...
Modeling the mechanical performance of metal produced with additive manufacturing (AM) has proven to be a challenging task. In the as-built state, these materials have been shown to exhibit strong heterogeneity and anisotropy. Even after post-processing, such as heat treatment or hot isostatic pressing and depending on the alloy, some...
Over the last few years, there has been a transition away from traditional engineering materials to new advanced materials that exhibit complex architectures with improved mechanical properties. Most of the inspiration for these new materials comes from nature, where organisms have evolved an immense variety of macro and nanoscale shapes...
Graphene oxide (GO) is a heavily oxidized version of graphene, which is often made by oxidative chemical exfoliation from graphite powders. The reaction decorates the graphene sheets with oxygen-containing functional groups including hydroxyl and epoxide groups on the basal plane, as well as carboxyl groups on the edge, rendering the...
Structural colors originate from the interaction between the incident light and a surface with periodic submicron structures. They enable the creation of a spectrum of nonfading colors, potentially replacing toxic metal oxides and conjugated organic pigments. However, significant challenges remain, including lack of contrast needed for the complete gamut of...
As more thermoelectric materials/devices make it into the market for various applications, severalaspects need to be explored and optimized, beyond simply targeting high conversion efficiency at
the material levels. One critical aspect is the guarantee of mechanical stability at both the material
and the device level, which demands deeper understanding...
Superalloys strengthened by γ′(L12)-precipitates in γ(f.c.c.)-matrix exhibit superior high temperature mechanical properties and environmental resistance over long periods of operation, making them ideal candidates for aerospace and energy conversion applications. The emerging class of superalloys based on Co-Al-W ternary system was identified with a melting temperature 50-100 ˚C higher than...
The past decade has seen the rapid progress of deep learning, which becomes a game-changing technique in different data-intensive domains, with the availability of large scale data, cost-effective computing hardware and more advanced learning theory and algorithms. Despite of the rapid progress of deep learning methods in daily-life applications, such...
SAMDI-MS (Self-Assembled Monolayers for MALDI-TOF Mass Spectrometry) couples the use of chemically-defined self-assembled monolayers of alkane thiolates on gold surfaces with MALDI-TOF mass spectrometry for rapid characterization of the surfaces. Reactions performed on the surfaces can be quantified directly by detection of the reaction substrates and products. This rapid detection...
Materials that exist as well-defined individual entities at the nanoscale typically have properties that sets them apart from their bulk form. Consequently, there has been much time and effort invested in developing new well-defined nanoscale entities, but few attempts to assemble them into bulk materials. On the other hand, there...
Melanin is a functional biopolymer most commonly associated with human skin pigmentation, where it serves as a radiation protection agent, shielding us from the harmful effects of UV radiation. However, melanin is also present in human ears, eyes, hair, and brains, serving a variety of functions. In fact, melanin...
Electrostatic interactions mediated by ionic environments play a central role in physical processes across materials science, chemistry and biology. Key biological phenomena, such as the condensation and packaging of DNA, ion transport across cellular membranes and the enzymatic action of proteins, rely on the complex interplay between nanoscale electrostatic, osmotic...
Superconductivity is a fascinating manifestation of quantum mechanics on a macroscopic scale that has led to greater insights of the strongly correlated physics of a large number of interacting electrons ever since its discovery $\sim$ 100 years ago in elemental Hg. The unconventional superconductors that are based on uranium offer...
At its core, the purpose of microscopy is to make objects and their underlying structures visible under high magnification. With the remarkable progress of electron microscopy, the sub-micron “high” magnification of light microscopy has been completely refashioned to encompass subatomic length scales. Unfortunately, higher-magnification does little to negate existing interpretability...
Plasmonic nanoparticles have very large absorption cross sections and can concentrate the local density of photon states on the nano scale. When they are coupled to molecules or semiconductor nanocrystals and form different hybrid nanostructures, various light-matter interaction processes can be significantly enhanced or manipulated, including optical responses like fluorescence...
Exploratory phase stability analysis in Materials Science has two primary goals: (a) Characterizing the evolution of the materials single phase field in composition space to identify solubility and electronic dopability limits and (b) Accelerated prediction of new phases of technological importance. In this thesis we reorganize defect theory --- the...
Colloidal crystal engineering with DNA offers new opportunities for materials scientists to build and program the structures of superlattices beyond what can be accomplished in Nature with atomic crystal lattices. Thus far, such materials primarily have been studied for their optical properties due to the insulating nature of the DNA...
The crystal structure of chalcogenides can vary from simple, ubiquitous structures of rock salt and zinc blende to unique structure types from the intricate packing of complex anionic building blocks. Exploratory synthesis and structural studies of novel chalcogenides containing these complex anions will augment the understanding of bonding in chalcogenides....
The era of quantum information science (QIS) can usher revolutionary new capabilities ranging from quantum computation to quantum sensing. At the core of these technologies is the fundamental unit of QIS, the quantum bit or qubit. The power of qubits over their classical counterparts lies in their ability to be...
Two-step, solar thermochemical water splitting using nonstoichiometric oxides has emerged as an attractive approach for large-scale hydrogen production. Perovskite-structured oxides, with their wide tunability, offer the potential for high fuel productivity at moderate operating temperatures. Given the vast chemical space, the materials development effort is carried out here in combination...
The heart of computational materials science lies in providing fundamental insights and understanding of materials behavior and properties across different scales. The significance of this task is highlighted by the Materials Genome Initiative and the emergence of computational tools and frameworks such as materials by design, microstructure sensitive design, and...
The successful isolation of graphene marked the advent of two-dimensional (2D) materials. Their atomically thin structures enable unprecedented electrical, optical, and mechanical properties, which have triggered significant research interests in the past decade. For instance, they are promising candidates for the fabrication of flexible electronics, biological sensors, battery electrodes, and...
Sea urchins are virtuosi of biomineralization, the process by which organisms build mineralized tissues. The embryonic animal exemplifies this with the formation of its endoskeletal spicule. The primary mesenchyme cells (PMCs) undertake spicule synthesis, which involves deposition of the initial granule, elongation of the spicule, and several choreographed changes...
A series of theories and models are developed and used to investigate the growth of protective oxide films on metal and alloy surfaces for cases in which Wagner's classical model of oxidation does not hold. First, irreversible thermodynamics is applied to formulate a model for the outward growth of rocksalt...
Nucleic acids not only are the building blocks of life but also a class of attractive macromolecular therapeutics. However, the delivery of therapeutic oligonucleotides into cells has been a major challenge due to their large size and highly negatively charged backbone. Spherical nucleic acids (SNAs) are a class of emerging...
Part I: Design of Photo-Responsive Molecules towards Biomedical ApplicationsThe use of light to control systems provides numerous advantages such as spatiotemporal precision, non-invasive penetration, and precise energy input. Specifically, molecules that undergo photoinduced cleavage, photoremovable protecting groups (PPGs) have emerged as an active area of research due to their broad...
Non-covalent and ion-specific interactions in the context of charged polymers are ubiquitous in nature and in synthetic applications. For example, mussels utilize metal-coordinate bonds to form tough underwater adhesion to a wide range of substrates. The sandcastle worm uses coacervation of oppositely charged polymers to build robust structures for self-defense....
Surface patterns that can reconfigure under external stimuli are important for tailoring diverse properties such as surface adhesion, optical transmittance, and wettability depending on the feature size and orientation. Wrinkling a stiff skin layer on a pre-strained elastomer substrate has emerged as a method to create responsive structures without using...
The complex structure of typical heterogeneous catalysts, where nanoparticles of active material are dispersed onto the surface of a thermally stable support with a high surface area, complicates the understanding of how the support can affect the resulting catalyst structure and properties. Using well-faceted and shape-controlled oxides as supports would...