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...
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...
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...
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...
Nanomaterials are increasingly incorporated in modern day life, from the biogenic viruses that cause pandemics and the mineral crystallites embedded alongside collagen in our bones, to the anthropogenic nanomaterials that are small but powerful components of sunscreen and paint, swimming pool algaecides and wound dressings, cancer treatments, bicycle frames, and...
Metallic conductivity and broken inversion symmetry were long thought to be contraindicated properties, under the assumption that long-range Coulombic interactions (screened by free charge carriers) were necessary for coordinated polar displacements. Within the past decade, the discovery of polar metals has prompted a rethinking of the relationship between metallicity and...
This thesis describes the synthesis and photophysical characterization of low-dimensionalmaterials—including thin-film semiconductors, colloidal quantum dots, and molecules—with the
broader motivation of integrating them into mixed-dimensional heterostructures with novel
responses to external stimuli. Due to their high surface area to volume ratio and incomplete
dielectric screening, mixed-dimensional heterostructures have high sensitivity...
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....
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...
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...
This thesis focuses on identifying structure-property-performance relationships in supported nanoparticle catalysts, where an active catalyst material is supported on a high surface area substrate. Identifying these relationships in supported nanoparticle catalysts can be quite challenging, as the complex structure of these catalysts results in numerous potential sources for changes to...
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...
Electrochemical devices play a vital role in the efforts towards a sustainable green future. Solid acid based electrochemical cells, employing super protonic CsH2PO4 (CDP) as the electrolyte component, offer unique application advantages due to their operability at intermediate temperatures 250°C. At these temperatures, one can achieve improved reaction kinetics over...
Nanocarriers are drug delivery vehicles that have at least one dimension at the nanoscale (10-9 m). Engineering the nanocarrier surface is a strategy for targeting drug delivery to specific cell types to enhance efficacy and minimize side effects. A useful analogy is to consider how the chassis of an automotive...
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,...
Materials science has been central to human advancement since time immemorial. There has always been curiosity around studying the processes required to extract materials, examine their structure, and ultimately tailor their properties to meet human needs. Over the last few centuries, the ability to tailor material properties was driven by...
Engineering heat transport in materials is essential for thermal management in a wide range of technologies, from batteries to thermoelectrics. Materials host a wide spectrum of heat-carrying phonons, which vary in their frequency, spatial extent, and degree of plane-wave character. This diversity in phonon properties leads to complex behavior, especially...
Over 10 billion tons of concrete are produced for the construction industry every year, making concrete the second most used substance on Earth, only surpassed by water. With such high importance as a building material, there is significant need for the ability to accurately model concrete behavior. As a quasi-brittle...
The development of functional materials with rationally designed hierarchical structure is an interdisciplinary challenge. Looking to nature for inspiration, we use small molecules that
engage in directed self-assembly through carefully tuned intermolecular interactions to construct
materials that have structure at multiple length scales. In this work, supramolecular structures
formed using...
Engineering responses of soft materials at hierarchical time and length scales is of great interest to both fundamental science and technological applications. In recent years, the hybridization between emerging soft condense matters and conventional hard condense matters keeps enriching the materials library of humankind and opens another largely-uncharted venue for...
In the face of a changing climate caused by anthropomorphic release of carbon dioxide and other greenhouse gases, major governments have committed to the reduction of CO2 and other emissions over time, requiring increased reliance on forms of carbon-free renewable energy. The inherent intermittency of renewable electricity sources creates a...
Solid oxide fuel and electrolysis cells (SOFCs and SOECs) must be engineered with the entire lifetime of their performance in mind. Electrochemical activity will decrease as degradative processes take effect, leading to higher overpotentials and decreased power outputs. Materials science and engineering can stave off these inefficiencies through an understanding...
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...
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...
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...
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...
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...
Thermoelectric devices utilize semiconducting n-type and p-type thermoelectric materials to convert heat into electricity. Despite their promise for deep space power generation or waste heat recovery, most high-performing thermoelectric materials reported in literature are absent in practical applications - partially due to inconsistent synthesis and poor mechanical performance. This work...
As the interest in rational synthesis for solid-state materials accelerates, there is an urgent need to understand the design principles concealed within these reactions. In situ material synthesis provides such an avenue to not only uncover these assembling rules, but also for finding new materials even in seemingly familiar phase...
Part I: Evaluating the relationship between Crosslink Kinetics and Thermodynamics with the hydrogel mechanics. The past two decades have witnessed a surge of applications built upon dynamic covalent chemistry (DCC), both attributed to the scope of developed reactions as well as their modularity.1-3 These reactions have comparable strengths to their...
The ability to control the crystalline ordering and morphology of polymeric nanomaterials is a grand challenge in the field of materials science, which could enable the development of functional materials able to solve long-standing problems in renewable energy and medicine. In this work, we explore a combination of supramolecular chemistry...
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...
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...
Protein-based biomaterials are widely used in biomedical applications and mechanical support because of their novel structural flexibility, biocompatibility and mechanical properties. Protein-based biomaterials outperform traditional synthetic materials in various environments as traditional materials lack the diverse chemical functionalities that proteins offer. Novel bioinspired techniques such as directed evolution offer the...
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...
Van der Waals, or layered, materials offer a flexible platform to tune properties via exfoliation down to the single- or few-layer limit; they are at the forefront of cutting-edge materials science and engineering research because of the innumerable ways to tune materials as a function of thickness or composition. Due...
Polymer and polymer/ceramic composites known as bone cements are commonly used in musculoskeletal reconstructive surgeries where bone tissue fixation, reinforcement, or void filling may be needed. Polymethylmethacrylate, PMMA, was the initial (and currently only) FDA-approved bone cement for bone-void filling applications yet faces many inherent material-based challenges that impacts its...
A fundamental materials science question is “why and how will this material form?” The experimental,computation, and time resources necessary to answer this question consume significant resources due to the
predominantly trial-and-error based approaches common in materials research. This dissertation reintroduces
a number of fundamental thermodynamics-based tools for the study of...
Understanding organization of soft materials on mesoscopic and nanoscopic scales is importantfor materials design. In this regard, non-van der Waals interactions such as hydrogen
bonding and electrostatic interactions offer great opportunities due to the richness and diversity
in morphological structures they produce. The primary reason for this is that these...
Since its introduction as an artist’s pigment in the earth 20th century, titanium white has become one of the most common white pigments. The early formulations of titanium white contained anatase, which has been studied to facilitate degradation of oil paint under UV illumination. Around the 1940s production shifted to...
Wireless power strategies are critical to system level implementation of bio-integrated devices. To achieve mechanically robust, manufacturable systems, batteries are often integrated as an on-board power source to support sensing, wireless communication and signal conditioning. Unfortunately, most sources of battery power use hazardous and environmentally harmful materials, which frustrate incorporation...
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...
Industrial processes heavily rely on catalysts to control product selectivity and lower energy barriers required for chemical transformations. Catalysts are most commonly solid heterogeneous catalysts that facilitate separations from reaction mixtures and enhance recyclability. Heterogeneous catalysts used in industrial processes exhibit efficacious results, but in certain instances drawing structure-function relationships...
Selecting the best material to deliver optimum performance in real-world applications is one of the most significant challenges in engineering. Hundreds of thousands of computationally-predicted, but experimentally unexplored materials exist today in the public inorganic material databases as candidates for consideration. This thesis discusses three projects in the domain of...
From the early usage of metallic thin films as mirrors tracing back to 2900 BC, to the modern thin film photonic circuits as a mature optical processing platform, and to the growing class of atomically-thin two-dimensional (2D) materials with diverse and tailorable properties, thin film materials have played an important...
In this dissertation, I summarize my findings of the dynamics of colloidal suspensions over a large range of volume fractions in two systems: drop impact and film rupture. The existence of a deformable surface in both these systems allows me to capture the consequences of non-Newtonian flow using high-speed imaging....
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...
The on-going demand for miniaturized optical and on-chip photonic systems of the future has led to a few potential solutions in the literature. Recent advances in van der Waals and 2-dimensional materials signal a bright future for the next generation, compact electronic and photonic devices. With reduced dimensionality and material...
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...
The extracellular matrix (ECM) is a masterwork of biology, and its development was a key part of the transformation from monocellular to multicellular life. With an ECM, cells acquired the ability to cooperatively build a dynamic support network that facilitated their movement, specialization, and communication. This ECM is a hierarchical...
Solid acid fuel cells confer unique advantages over nearby technologies, such as polymer electrolyte membrane fuel cells (PEMFCs) or solid oxide fuel cells (SOFCs), due to the solid acid electrolyte – a solid-state, anhydrous, intermediate-temperature proton conductor.Despite these encouraging unique properties, solid acid fuel cells have performed unfavorably in comparison...
Conventionally cross-linked polymers, which comprise the vast majority of commercial thermosets, cannot be decross-linked after curing or flow upon heating. Therefore, they cannot be effectively recycled into high-value products at end-of-life. Their lack of recyclability is due to the permanent cross-links, which restrict the flow of the chains in the...
Recent developments have enabled L12-strengthened Co-based superalloys, which have thepotential to surpass Ni-based superalloys as the material of choice for the hottest sections of turbine
blades due to cobalt’s 40 ºC higher melting point. The most-studied branch of Co-based
superalloys are based on the L12 phase Co3(Al,W); however, there is...
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...
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...
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...
The on-going demand for miniaturized optical and on-chip photonic systems of the future has led to a few potential solutions in the literature. Recent advances in van der Waals and 2-dimensional materials signal a bright future for the next generation, compact electronic and photonic devices. With reduced dimensionality and material...
Nanomaterials present an exciting landscape of innovation at length scales below 100 nm, wherein controllable synthesis and materials metrology have led to tunable structure-property relationships and next-generation products. The disruptive field of nanotechnology is poised to capitalize upon the exotic chemistry and physics of these nanomaterials to enable more efficient...
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...
Single-use plastic waste pollution will cause significant harm to the environment if left unaddressed. One possible mitigation strategy is to develop processes, e.g. catalytic hydrogenolysis, that can convert (i.e. upcycle) waste plastics into value-added products capable of participating in a circular economy. Platinum (Pt) catalysts on strontium titanate nanocuboid supports...
Thermoelectric devices convert between temperature gradients and electricity, implying numerous applications, such as powering exploratory space vehicles, industrial waste-heat recovery, and solid- state refrigeration. Thermoelectric devices consist of doped p-type and n-type semiconductor legs, and the overall device efficiency depends on the transport properties of these semiconductor materials. High-performing thermoelectric...
The field of materials discovery is undergoing an unprecedented transition from laboratory tocomputer. Behind this transition is the new ability to accurately compute material properties, especially
energetic stability, from first principles with density functional theory (DFT). However,
DFT remains computationally expensive, and DFT-based materials discovery is intractable, especially
in high...
Metal–Organic Frameworks (MOFs) is a class of material comprising organic linkers and inorganic, metal-ion-containing nodes, with diverse functionalities and wide-range of applications. Because of their porous nature and functional nodes and linkers, they are competent candidates for gas storage, separation, catalysis, and so on. Most MOFs, however, are intrinsically insulating,...
Renewable energy technology, more so than ever before, is critical to the survival of humanity. For decades, concentrated efforts into designing and developing such novel devices resulted in the innovation of solar-driven photovoltaics that were competitive with nonrenewable alternatives. This thesis explores the dynamic behavior of alternative material candidates that...
Large scale adoption of sustainable technologies for energy productionand storage can be greatly facilitated by scientific advances impacting efficiency, cost and availability. The study of materials is instrumental in both upgrading the performance of existing technologies and enabling the development of new ones, and ab-initio methods and machine learning represent...
The relationship between the structure and function of proteins is a fundamental problem in biology with implications for the future of biotechnology and global health. For example, changes to the structure of a coronavirus spike protein led to a global pandemic where our best defenses were vaccines that could only...
Dental enamel is a complex bio-composite with compositional and structural features across a wide range of length scales. Defects in these features can compromise enamel’s ability to protect the tooth, resulting in adverse health outcomes. Acquired defects like tooth decay are familiar to most people and are the subject of...
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...
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...
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...
Drying oils have been used as a binding medium for oil paints since the 15th century. These oil paints transition from a liquid-like paste to a solid-like film as a result of crosslinks forming between the oil molecules. These reactions have been extensively studied chemically, but other material properties are...
Recent progress in semiconductor synthesis and photophysics has revealed a host of new materials with exciting properties for applications in optoelectronic devices such as sensors, photovoltaics, solid state lighting, and more. One of the most significant recent additions to the field is the class of hybrid and inorganic materials that...
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...
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...
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...
Polymers occupied nearly every facet of our daily lives, and enhancing their mechanical and fracture properties has long been an important topic in the field of polymer science. Based on the various need in applications, polymers are designed to have a range of characteristics such as tackiness, optical properties, mechanical...