The assembly of nanoscale building blocks into larger ensembles with well-defined architecture has the potential to create entirely new classes of designer photonic and plasmonic metamaterials with unique properties not found in nature. Electromagnetic metasurfaces, or 2D metamaterials, operating at optical wavelengths are of particular interest due to ease of...
This dissertation presents research on solid oxide fuel cell (SOFC) cathodes. It specifically covers two main topics: the electrochemical performance of porous two-phase composite cathodes, and the degradation mechanisms of porous single-phase mixed conducting cathodes. Current-voltage measurement and electrochemical impedance spectroscopy were used extensively to evaluate the cell performance. The...
Self-assembly is an important process in biological system to build various bioactive structures from small amphiphilic molecules. The structural versatility of amphiphile self- assembly also provides a unique platform for the design of functional soft materials with controllable structural features. However, little is known about the correlation between external stimuli,...
Patterning hierarchical structures in three-dimension (3D) has created nature-inspired functional surfaces. Gecko feet structures have been mimicked for reversible adhesive properties, shark skin for reduced drag, and lotus leaves for self-cleaning surfaces. Rational design of out-of-plane patterns across multiple length scales is crucial because each micro- and nano-feature has different...
Charge-containing polymers have received considerable attention for many decades, as these polymers combine the flexibility of polymer chains with electrochemical properties of the ions to provide a highly tunable, chemically and mechanically versatile class of materials. These materials have found use in energy conversion devices, high-density energy storage devices such...
Sparked by the isolation of graphene in 2004, the research community has developed a family of 2D materials with distinct functionalities, enabling rapid demonstrations of entirely 2D devices with applications in energy, electronics, sensors and medicine. The desire to capitalize on the fantastic properties of 2D materials motivates ongoing efforts...
Complex oxides show great potential for future devices as they offer functionalities beyond what can be delivered by conventional semiconductors. Among the complex oxides, the ABO$_{3}$ perovskite oxides are the most studied and engineered in the form of thin films and heterostructures. This thesis applies powerful synchrotron-based X-ray characterization tools,...
etal particles at the nanoscale display unique physical, chemical, and optical properties corresponding to their size, shape, and ligands. These factors can be manipulated to target specific biomedical applications, such as drug delivery and sensing, through functionalized surfaces. The development of specialized synthetic methods for the precise control of nanoparticle...
Plasmonic nanostructures are capable of trapping and confining light at the nanoscale, leading to interesting optical phenomena involving enhanced light-matter interactions. These responses arise in two forms: surface plasmon polaritons propagating on the surface of metal films and localized surface plasmons confined to the surface of metal nanoparticles. Plasmonic modes...
Two-dimensional materials’ “all-surface” architecture presents a new paradigm for investigations into electron confinement effects and surface phenomena. However, synthesizing, characterizing, and ultimately engineering the properties of 2D materials represents a formidable challenge. This thesis presents several cases of isolating novel 2D materials via vapor-based syntheses. Vapor-based syntheses allow for reproducible...