This dissertation investigates the incorporation of Photosystem I (PSI), a supramolecular protein complex that participates in the light reactions of photosynthesis, into electrochemical systems intended for the conversion of photonic energy into chemical energy and electricity. First, I describe the fabrication of nanoporous gold leaf electrode films and detail the process by which they are decorated with PSI complexes. I further explain how the feature size of the substrate must be tuned such that the pores may accommodate multiple PSI complexes in order to produce enhanced photocurrent with respect to a planar electrode. Second, I develop a kinetic model for the photocatalytic effect produced by a monolayer of PSI on a planar electrode. I solve the resulting system of partial differential equations numerically and use the simulation to extract kinetic parameters from experimental data. Third, I describe the construction of stand-alone PSI-based photoelectrochemical cells, demonstrate their light transduction capabilities, and show that the devices continue to produce photocurrent for at least 9 months after their fabrication. Fourth, I present a method to deposit multilayer films of PSI by vacuum-assisted assembly. I characterize the resulting films optically and electrochemically and show that photocurrent production increases with thickness of the films. Furthermore, I demonstrate the largest photocurrent responses of the films are produced in response to irradiation by light of wavelengths that correspond to peaks in the films absorbance spectra. Finally, I offer general perspectives conclusions about the results presented herein and outline future directions in which this project may progress.

Facile one-step syntheses of colloidal EuS, EuTe and Te nanocrystals are presented in this thesis. The formation of single crystalline monodisperse nanocrystals, with sizes finely controlled by synthetic conditions, was confirmed by x-ray diffraction and high resolution transmission electron microscopy analysis. The exciton transition of EuS and EuTe nanocrystals blue-shifts to higher energies with decreasing particle sizes, as revealed by optical absorption and photoluminescence measurements. The feasibility of synthesizing monocrystalline EuS nanorods and EuTe nanospindles was also demonstrated, making them potentially viable materials for device applications. Low-temperature magnetic measurements show that as-synthesized EuTe nanoparticles show pronounced superantiferromagnetic transition between. Te nanocrystals were well separated into two size regimes and assembled into films by eletrophoretic deposition.

This dissertation is concerned with the development of a decision making framework which companies and organizations can use in establishing an effective carbon disclosure strategy. This is accomplished by first researching the current practice of carbon disclosure both in theory and in practice. Next, a benchmarking study was conducted analyzing the carbon disclosure efforts of a sample of 83 U.S.-based companies across nine industrial sectors. Finally, a decision making methodology framework for determining carbon information disclosure strategy is presented that was developed as part of this research and validated by peer-review process.

Medical decision making is a complex cognitive process involving multiple stakeholders and factors. The increased amount of information, pace at which information is obtained, source of that information, and the experience of the decision maker, both the physician and the patient can affect the medical decision making process. This research investigated two independent factors that may influence decision making: 1) the usage of a medical registry and 2) the influence of the educational background of the decision makers. This research found that registry users and non-users follow different decision making processes; and that registry users utilize the information attained from the registry in their decision making process. Decision makers of varying educational disciplines are influenced differently when presented with difficult medical decisions, and innumeracy skills are limited even in a highly educated population. Finally as medical registries are shown to impact medical decisions, and medical information is increasingly being requested by the general public, it is vital that an understanding of how the educational background of patients may impact their view of the information provided and what other influences may lead one to follow different decision rules.

Silicon photonic crystal (PhC) cavities have attracted great interest recently due to their ability to highly confine light both spatially and temporally. The small mode volumes and long photon lifetimes associated with PhC cavities are desirable for sensing applications, which utilize the sensitivity of the light-matter interaction (LMI) inside the cavity region. In pursuit of enhancing the LMI of PhC cavity-based sensors, this dissertation focuses on the design, simulation, fabrication, and testing of Multiple-Hole Defect (MHD) PhC cavities. MHD PhCs are 2D silicon slab PhCs with small, sub-wavelength sized defect holes placed directly into point defect PhC cavities. The insertion of MHDs increases the spatial overlap in the PhC cavity between the modal field and any surface perturbations, such as captured molecules, made within the cavity. Several designs of MHD PhC cavities were explored using Finite-Difference Time Domain (FDTD) simulations in order to understand the effect of MHD integration on the PhC cavity resonance frequency and quality factor. It was found that the LMI is maximized when defect holes are placed in regions of highest field localization within PhC cavities. The sensitivity of MHD PhCs to bulk refractive index changes was investigated by wetting the structures with different fluids. The bulk index sensitivity of MHD PhC cavities with 80 nm diameter defect holes was found to be 98 nm/RIU, which is larger than comparable PhC cavity sensors without defect holes. The sensitivity of MHD PhCs to small refractive perturbations on the sensor surfaces was explored by binding small-molecules to the surfaces of MHD PhCs treated with either a native oxide or an atomic layer deposition (ALD) silicon dioxide. It was found that the sensitivity of PhC sensors to a 0.8 nm thick, surface-bound aminosilane monolayer was increased by 160% when three 60 nm diameter defect holes were added to an L3 PhC cavity. These results represent the initial steps towards highly sensitive, compact, label free optical sensors, and with further improvements could result in improved handheld lab-on-chip type sensor devices.

During the pathogenic blood stage of a malaria infection, the Plasmodium parasites degrade hemoglobin as a source of nutrition. As a consequence, free heme, known to be toxic to the parasite, is released. It is believed that the parasite circumvents heme toxicity by sequestering the heme molecules into a dark brown crystalline material known as hemozoin. The molecular details associated with the formation of hemozoin and its synthetic counterpart, beta-hematin, are presented in this dissertation. Firstly, the biological mediator of hemozoin formation was investigated. Neutral lipid droplets (NLDs) were shown to be sufficient at mediating the production of brown pigments that are morphologically and chemically identical to hemozoin. Optimal partitioning of heme into NLDs was pH dependent with maximal heme conversion at a pH condition similar to that of the parasites digestive food vacuole, the biological site of crystallization. The rate of beta-hematin formation was rapid enough to protect the parasite from heme toxicity. Secondly, the interfacial interactions between lipid molecules and heme were investigated using Langmuir-Blodgett monolayer creation techniques. Comparisons of these surface pressure-area isotherms revealed that the biological composition of neutral lipid is characterized by disordered packing of lipids. This fluid lipid surface may account for the low activation energy measured for beta-hematin formation associated with NLDs. Substituted protoporphyrin IX compression studies suggest that hemozoin nucleation begins when the propionic group of a heme unit anchors to the polar head group of the lipid molecules. Thirdly, crystallization parameters associated with beta-hematin formation was examined using various solvent conditions to facilitate heme solubility. The formation of beta-hematin using the aprotic solvent dimethylsulfoxide and some polyethyleneglycols demonstrates that crystallization is accelerated by increasing heme solubilization in acidic conditions, resulting on increased dispersion of amorphous heme precipitates. Crystallization data support the notion that modulation of the water activity is important mechanism to support spontaneous heme crystallization. Futhermore, through proper manipulation of solvent properties, the morphologies of beta-hematin can be controlled. Finally, beta-hematin crystals were applied to phage display technologies to identify short peptide sequences that specifically recognize select crystal face. Isolated peptides were sufficient at mediating beta-hematin formation.

<p> Zinc oxide films or quantum wells and plasmonic elements, comprising rough metal films and nano-cylinder arrays of Ag, Al or Au, constitute an especially interesting model system for studying plasmon-exciton interactions. This dissertation focuses on the energetics, dynamics and control of the coupling between band-edge excitons and luminescent defect complexes in ZnO thin films and quantum wells, on the one hand, and localized or propagating plasmons in metallic films and nanostructures on the other. <p> Multilayer structures of ZnO, MgO, and Ag or Au with varying thicknesses of MgO provide a workbench for analyzing interactions as a function of plasmon-emitter separation. In particular, the coupling of Ag and Au SPPs to excitons via Purcell-like interactions, and the dipole-dipole scattering of Ag and Au LSPs with ZnO DAPs were analyzed via photoluminescence and pump probe spectroscopy. Simultaneous transmission and reflection pump-probe spectroscopy performed on samples annealed under varying conditions provided an understanding of the ZnO defect dynamics, and demonstrated the dramatic Purcell enhancement of a long-lived Zn interstitial defect state. The selective decay rate enhancement of individual quantum emitters by tunable surface plasmon resonances should make available emitters currently too inefficient to be commercially practical. <p> Aluminum nanodisc arrays deposited on ZnO/Zn0.85Mg0.15O single quantum wells provided a flexible template for the investigation of LSP-exciton coupling. By optimizing the LSP resonance and the QW emission, heterostructures were fabricated that demonstrated a hybridized Al LSP quadrupole â ZnO QW exciton state in the confocal extinction spectra, a strong coupling phenomenon that provides the foundation for the fabrication of nano-designed heterostructures with tunable dielectric functions throughout the near to mid ultraviolet spectrum.

This dissertation furthers the understanding of diamond as a material for cold cathode field emission. Although diamond has proven to be an excellent emitter with orders of magnitude more current at lower fields than competing technologies, fabrication yield has been a persistent issue. Irregularities in emission behavior between tips have historically been attributed to anomalies in the fabrication process which results in sharp or less sharp diamond tips. However, differences are observed in electron emission thresholds even between tips that appear by conventional analysis to be equally well formed. By enabling analysis of the emitter surface and sub-surface, the methods developed herein permit analysis of diamond tip growth and provide a feedback mechanism for optimization of field emitter properties. This dissertation contains first-time measurements of sharp-tipped diamond cold cathode field emitters imaged by transmission electron microscopy. These preliminary observations correlate hitherto unknown diamond cold cathode emitter nanostructure with emission behavior.

This research investigates the organizational and collective impacts of participation in industry technology roadmap (ITR) development; further, characteristics of the roadmapping collective make-up and processes that contribute to these impacts are evaluated. A model is developed, relating roadmapping characteristics to organizational and ITR collective impacts of creating an industry roadmap. The model includes: 1) motivations for organizations to participate in the development of an ITR, 2) industry-related motivations for developing a roadmap, 3) stakeholder-based structure and processes used to create the roadmap, 4) characteristics of the roadmap document, 5) industry clockspeed (pace of change), and 6) organizational impacts from ITR development (e.g. technology planning, pace of innovation, collaborative activities and partnerships, implementation of new technologies, etc.). The model is evaluated using survey data obtained from organizational participants (N=128) in ITR development from six industries (concrete, electronics, forest products, magnesium, metal casting, and powder metallurgy). Findings suggest that motivation of an organization to participate in the roadmapping effort, organizational executive support for the effort, and the research and development (R&D) experiential level of an organizational representative in the ITR collective, impact the individual organization; while the aggregate motivation of participating organizations, aggregate R&D experience of the organizational participants, thoroughness and clarity of the roadmap document, and industry clockspeed, correlate with an increased impact on organizations as a collective.

Semiconductor nanocrystals of CdSSe exhibiting chemical composition gradients are synthesized via a facile, one-pot synthesis. Varying degrees of gradation are observed as growth temperatures are manipulated to alter rates of reactivity for anionic precursors. Stoichiometries, with growth time and change in temperature, are determined using Rutherford backscattering spectroscopy (RBS) to demonstrate chemical composition gradients. Sizes and structures of compositionally graded CdSSe nanocrystals are determined using transmission electron microscopy and X-ray diffraction techniques, respectively. We employ absorption spectroscopy and photoluminescence techniques to elucidate corresponding optical properties. Nanocrystals with chemical composition gradients demonstrating enhanced luminescence efficiency could be the key to improved nanocrystal optical performance.