Physical Sciences and Mathematics Commons^™

High-Pressure Studies On The Transition From Red Phosphorus To Black Phosphorus, Heng Xiang

Electronic Thesis and Dissertation Repository

Black phosphorus (BP) is a promising material in many research fields. However, the transition process from amorphous red phosphorus (ARP) is elusive and hence hinders large scale synthesis and applications. This work describes the application of the high-pressure method to study the transition process from ARP to BP.

In this thesis, the following three objectives were achieved: (1) to understand the mechanism of the transition, (2) to facilitate the synthesis of BP by taking the advantage of less pure ARP, (3) to propose new methods of synthesizing BP-based materials, such as the moderately oxidized BP and the black phosphorus/ amorphous …

Characterization And Computational Modelling For The Garnet Oxide Solid State Electrolyte Ta-Llzo, Colin A. Versnick

Electronic Thesis and Dissertation Repository

The all-solid-state-battery (ASSB) serves as a promising candidate for next generation lithium ion batteries for significant improvements in battery safety, capacity, and longevity. Of the material candidates researched to replace the conventionally used liquid electrolyte, the garnet oxide Ta-LLZO (Li_6.4La₃Zr_1.4Ta_0.6O₁₂) has received much attention thanks to its high chemical and electrochemical stability, and ionic conductivity which rivals that of liquid electrolytes. While much investigation has taken place regarding the electrochemical performance of Ta-LLZO, much less is known about the micromechanics, including microstructural characterization, stress and strain development, and material failure …

Novel Avenues Toward Controlling The Photophysical Properties Of Ultra-Small Silicon Quantum Dots, Mohammed Abdelhameed

Electronic Thesis and Dissertation Repository

Quantum dots (QDs) have attracted an increasing attention in the last decade over many conventional organic dyes. This is due to their unique optical properties including broad absorption spectra, high photostability, and size-tunable photoluminescence (PL). However, some toxicity concerns associated with traditional quantum dots have hindered their wide applicability. Interestingly, silicon quantum dots (SQDs) have been shown to be more advantageous than most of QDs thanks to their excellent biocompatibility and biodegradability, low cytotoxicity, and versatile surface functionalization capability. Thus, SQDs are promising candidates for various biological and biomedical applications such as bioimaging, biosensing, and photodynamic therapy. Unfortunately, only a …

Shape-Controlled Nanoparticles As Effective Catalysts For Proton Exchange Membrane (Pem) Fuel Cells, Ali Feizabadi

Electronic Thesis and Dissertation Repository

Polymer electrolyte membrane fuel cell (PEMFC), is considered a promising candidate for the next generation power sources in transportation, stationary and portable applications. However, oxygen reduction reaction (ORR), one of the key reactions occurring on PEMFC is kinetically slow; this has limited performance and further advancement in this kind of fuel cells. Thus, improving the PEMFC efficiency requires a thorough understanding of the ORR mechanism on the desired catalyst. To address the above-mentioned demands, the scope of this thesis is focused on the fundamental understanding of facet-controlled nanoparticles, metal-support interactions, and bimetallic platinum catalysts, utilizing synchrotron-based X-ray absorption, X-ray photoelectron …