Electrochemical cell devices are increasingly being sought for energy conversion and storage applications due to their high efficiencies and their potential for operating free of greenhouse gas (GHG) emissions. Solid Acid Electrochemical Cells (SAECs), which most commonly employ CsH2PO4 (CDP) as the electrolyte component, are uniquely suited to meet the...
Two-dimensional (2D) materials and heterostructures have attracted significant attention for a variety of nanoelectronic and optoelectronic applications. At the atomically thin limit, the material characteristics and functionalities are dominated by surface chemistry and interface coupling. Therefore, methods for comprehensively characterizing and precisely controlling surfaces and interfaces are required to realize...
Throughout history, the development of materials has relied heavily on the empirical judgment of scientists and engineers and on prolonged experiments proton to errors. Due to the complexity of material behavior, successful discovery of new candidates has been serendipitous, and down-selection of candidates remains a time-consuming process that requires repetitive...
Use of bio-renewable polysaccharides to produce materials with a high technological impact has gained a lot of attention recently. Efforts have been made, for example to produce triboelectric generators from cotton, as well as, nanostructures of chitosan gels for drug delivery. Another well-known example is the use of β-Cyclodextrin (β...
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...
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...
Deformation in materials with a hierarchical microstructure is expected to be complex because of the interaction between the units that form such a microstructure. The complexity of deformation would be even higher when additional inelastic deformation modes are active in such materials, apart from traditional elastic and plastic deformation modes....
This dissertation presents a comprehensive study of thin-film LiMn2O4 (LMO) cathodes applied in lithium ion batteries (LIBs). The primary aim was to establish fundamental understanding of the relationship between interfacial LMO chemistry/electrochemistry and its detrimental drawback, i.e. fast capacity fade over long term cycling, and then develop effective mitigation methods....
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...
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...
Semiconductor nanowires, such as group IV and III-V nanowires, shows distinct electrical, optical and mechanical properties from their bulk counterparts due to their nanoscale size and 1-D morphology. For example, the quantum confinement effect modulates the band gap of a semiconductor nanowire when its diameter approaches or below the exciton...
The demand for low cost, unconventional electronics requires new materials with unique characteristics that the traditionally used silicon-based technologies cannot provide. Metal oxide semiconductors, such has amorphous indium gallium zinc oxide (a-IGZO), have made impressive strides as alternatives to amorphous silicon for electronics applications. However, to achieve the full potential...
There is no group of materials as diverse, complex, and ubiquitous as polymers. From plastic bags, to rubber tires, electronics, food packaging, water filtration and even aerospace applications, the penetration of polymer materials into all aspects of life make them very important materials throughout all engineering fields. However, this breadth...
Low-dimensional materials have emerged as a promising platform for ultrathin electronic and optoelectronic devices. The span of electronic properties covers the spectrum from metallic through small and medium bandgap semiconductors to large bandgap insulators, providing all the necessary components to fabricate a variety of devices. Compared to bulk-semiconductor based devices,...
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,...
Mixed-dimensional heterojunctions between two-dimensional (2D) materials and organic semiconductors is a rapidly growing field. This is motivated by the promise of leveraging the extraordinary properties of 2D materials with the synthetic tunability and reconfigurability of organic electronics, allowing the realization of new physics or devices that are not possible in...
Thermoelectric materials are of particular interest in a variety of fields because of their ability to directly convert heat to electricity (and vice versa), however, they struggle to gain widespread adoption because of their low efficiency. A common strategy in the field of thermoelectricity is to introduce material defects into...
Solvent-rich polyelectrolyte complexes display a wide range of rheological properties, when different environmental parameters are applied. Due to the low energy barrier of the complexation (~10 kT), these materials possess tunable properties, with the states of these materials varying from Newtonian liquids to very tough hydrogels. This thesis aims to...
The advancement of nanotechnology is at least partially dependent on the ability to synthesize and arrange complex nanostructures on a substrate. Nanolithography, or the patterning of materials at the sub-micrometer length-scale, has been traditionally performed using a number of methods such as conventional photolithography, ion-beam etching, and electron-beam lithography. While...
Connecting structure and function in nanoscale engineered materials and devices relies on the analysis of the fundamental arrangement of matter, frequently under dynamic conditions. The demand to image structures at fundamental length scales has touched inorganic materials, biology, and frequently hybrid hard/soft materials with unique phenomena driven by heterogeneous components....
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...
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...
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...
The Controlled, Site-Isolated Synthesis of Polyelemental Nanostructures in Polymer Nanoreactors Pengcheng Chen Polyelemental nanoparticles are an attractive class of materials due to their potential applications, which span the fields of catalysis, plasmonics, electronics, magnetics, targeted drug delivery, and bio-imaging. However, conventional synthetic methods for such structures are limited, especially when...
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...
NiTi shape memory alloy (SMA) has drawn a great deal of attention for its various applications in the medical field (orthodontics, cardiovascular stents technology, etc.) and in other engineering fields (aerospace, aircraft, automotive, etc.) as it shows shape memory effect, superelasticity and biocompatibility. The fatigue-related issues, however, are pronounced in...
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 high-temperature oxidation/reduction behaviors of iron and its oxides are important to a variety of energy conversion and storage technologies, such as the solid-oxide iron-air battery and chemical looping combustion. The useful lifetime of iron redox materials is limited, however, by structural degradation arising from (i) sintering, accelerated by phase...
High performance polymers and their composites have wide ranging application in advanced and emerging material systems. The macroscale performance of these advanced materials is often defined by interfaces that induce nanoscale changes in the microstructure or molecular conformations (termed the ‘interphase’) of the polymer. Atomic force microscopy (AFM) is an...
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...
Localized corrosion involves the selective attack of a metal at a small, exposed site. This can be particularly devastating for load-bearing structures like bridges, which can fail catastrophically even with very little material loss. Unfortunately, such corrosion is very hard to prevent, predict, and detect. Corrosion can be prevented by...
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...
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...
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...
The study of magnetic frustration has attracted considerable interest in the fields of materials science and condensed matter physics. Artificial Spin Ices (ASIs) are the primary systems in which magnetic frustration has been studied. To date, most studies on ASIs have been on fully periodic systems. In this thesis, we...
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...
Plasmonic metasurfaces are leading the development of next-generation optical devices with unprecedented compactness and functionality. In contrast to bulk refractive optics, these planar surfaces manipulate light with rationally designed subwavelength building blocks. This thesis focus on how emerging materials and design methods advance the eld of metasurfaces. Chapter 1 reviews...
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...
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...
The effect of Alkali-Silica Reaction (ASR) on concrete mechanical behavior and the multi-physics considerations that come along are highly complex. Hydration and other chemical reactions occur at the micrometer scale. Hygro-thermal phenomena and concrete cracks due to ASR are typically studied at the meso-scale, i.e. at the aggregate level. At...
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...
Ordered arrays of metallic nanoparticles (NPs) are a promising platform for technological applications and fundamental investigations due to their ability to excite surface lattice resonances (SLRs). SLRs can support extremely high local electric fields that have been used to realize exotic physical phenomena. The open cavity architecture lends itself to...
This dissertation explores ways to utilize physical parameters at the nanoscale interface to control the properties of mixed-dimensional heterojunctions (MDHJs). MDHJs combine the desirable properties of different classes of low-dimensional nanomaterials (materials that are quantum confined in at least one dimension). While MDHJs have achieved superlative performance for a variety...
As conventional electronic materials approach the device scaling limits, new types of materials and structures have been examined for potential use in future electronic and optoelectronic applications including transistors, light emitting diodes, and solar cells. In recent years, atomically thin or two-dimensional (2D) transition metal dichalcogenide (TMD) materials have emerged...
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...
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...
Physiochemical phenomena in aqueous systems, such as corrosion, catalysis, and energy storage, are driven by the molecular-scale interactions of ionic species with charged solid surfaces. In particular, an electrical double layer (EDL) of ions forms within nanometers of a charged surface. The properties of the EDL have been explored from...
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...
Organic semiconductors are an active area of research with great promise for delivering next generation electronics and clean energy technologies. As the field matures, understanding the connection between molecular structure, materials’ properties, and device performance will be critical in finding the right material for an intended application. An effective strategy...
The commercial success of personal computing has led to the rapid creation and proliferation of diverse electronic systems including desktops, laptops, tablets, mobile devices, and embedded systems. For the past five decades, silicon has served as the base material for computing electronics. However, with increasing demand for unconventional electronics (e.g.,...