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...