Materials Science and Engineering Commons^™

Designing & Building A Microwave Plasma Reactor For Graphene Synthesis, Aviv Zohman, Jerry Larue

Student Scholar Symposium Abstracts and Posters

Graphene’s remarkable electrical, optical, and chemical properties make it a promising successor to indium tin oxide for applications in flexible, transparent electronics. However, efforts to manufacture graphene have been hindered by inefficient synthesis and transfer methods. Chemical vapor deposition (CVD) is commonly used to produce graphene. CVD starts with a blank surface onto which a chemical vapor is deposited to create a single graphene layer. CVD requires extreme temperatures, so only substrates with high melting points are applicable, like metals. This excludes insulative substrates such as polymers which are essential to transparent and flexible devices. Therefore, a subsequent process transfers …

Investigation Of Bipolar Electrochemically Exfoliated Graphene For Supercapacitor Applications, Iman Khakpour

FIU Electronic Theses and Dissertations

Developing a reliable, simple, cost-efficient and eco-friendly method for scale-up production of high-quality graphene-based materials is essential for the broad applications of graphene. Up to now, various manufacturing methods have been employed for synthesizing high quality graphene, however aggregation and restacking has been a major issue and the majority of commercially available graphene products are actually graphite microplates. In this study, bipolar electrochemistry techniques have been used to exfoliate and deposit graphene nanosheets in a single-step process to enable high performance device application.

In the first part of this study, bipolar electrochemistry concept is utilized to design a single-step and …

Modelling Palladium Decorated Graphene Using Density Functional Theory To Analyze Hydrogen Sensing Application, Sameer Kulkarni

Mechanical Engineering Undergraduate Honors Theses

Graphene is an exciting new material with many promising applications. One such application of graphene is gas sensing, when adsorbed with transition metals, notably Palladium. Therefore, it is of paramount importance to have appropriate ab initio calculations to calculate the various properties of graphene under different adsorbates and gasses. The first step in these calculations is to have a functioning base Density Functional Theory (DFT) model of pristine graphene decorated with Palladium. The computational methods described in this paper has yielded results for pristine graphene that have been confirmed many times in previous experimental and theoretical studies. Future work needs …

Electrical Characterization Of Graphene And Nanodiamond Nanostructures, A Z M Nowzesh Hasan

Doctoral Dissertations

The electrical characterization on two-dimensional carbon-based graphene and nanodiamond materials was performed to improve charge transport properties for the label-free electrical biosensors. The charge transport in solution-gated graphene devices is affected by the impurities and disorders of the underlying dielectric interface and its interaction with the electrolytes. Advancement in field-effect ion sensing by introducing a dielectric isomorph, hexagonal boron nitride between graphene and silicon dioxide of a solution-gated graphene field-effect transistor was investigated. Increased transconductance due to increased charge carrier mobility is accompanied with larger ionic sensitivity. These findings define a standard to construct future graphene devices for biosensing and …

Surfactant Driven Assembly Of Freeze-Casted, Polymer-Derived Ceramic Nanoparticles On Grapehene Oxide Sheets For Lithium-Ion Battery Anodes, Ali Zein Khater

Honors Undergraduate Theses

Traditional Lithium-Ion Batteries (LIBs) are a reliable and cost-efficient choice for energy storage. LIBs offer high energy density and low self-discharge. Recent developments in electric-based technologies push for replacing historically used Lead-Acid batteries with LIBs. However, LIBs do not yet meet the demands of modern technology. Silicon and graphene oxide (GO) have been identified as promising replacements to improve anode materials. Graphene oxide has a unique sheet-like structure that provides a mechanically stable, light weight material for LIB anodes. Due to its structure, reduced graphene oxide (rGO) is efficiently conductive and resistive to environmental changes. On the other hand, silicon-based …

Fabrication And Characterization Of Hybrid Nanocomposites By Matrix Assisted Pulsed Laser Evaporation, Songlin Yang

Electronic Thesis and Dissertation Repository

Different methods have been applied to deposit hybrid nanocomposites which can be applied in various fields due to their light weight and multifunctional properties. Here, matrix assisted pulsed laser evaporation (MAPLE) equipment with 532 nm Nd:YAG laser is applied to fabricate three types of hybrid nanocomposites on different substrates.

Chemical synthesized FeCo nanoparticles were deposited on graphene sheets by MAPLE technique (laser fluence: 300 mJ/cm²). The effects of deposition time (t) on particle amount, shape and size have been investigated. Yttrium barium copper oxide (YBCO) materials are one type of high-temperature superconductive materials and …

Graphite And Graphene-Oxide Based Pgm-Free Model Catalysts For The Oxygen Reduction Reaction, Joseph Henry Dumont

Nanoscience and Microsystems ETDs

The world currently relies heavily on fossil fuels such as coal, oil, and natural gas for its energy. Fossil fuels are non-renewable, that is, they draw on finite resources that will eventually dwindle, becoming too expensive or too environmentally damaging to retrieve. One alternative source of energy are fuel cells, electrochemical devices that convert chemical energy to cleanly and efficiently produce electricity. They can be used in a wide range of applications, including transportation, stationary, portable and emergency power sources. Their development has been slowed by the high cost of PGM electrocatalysts needed at both electrodes as well as sluggish …

Surface Energy In Bond-Counting Models On Bravais And Non-Bravais Lattices, Tim Ryan Krumwiede

Doctoral Dissertations

Continuum models in computational material science require the choice of a surface energy function, based on properties of the material of interest. This work shows how to use atomistic bond-counting models and crystal geometry to inform this choice. We will examine some of the difficulties that arise in the comparison between these models due to differing types of truncation. New crystal geometry methods are required when considering materials with non-Bravais lattice structure, resulting in a multi-valued surface energy. These methods will then be presented in the context of the two-dimensional material graphene in a way that correctly predicts its equilibrium …

C-Mems Based Micro Enzymatic Biofuel Cells, Yin Song

FIU Electronic Theses and Dissertations

Miniaturized, self-sufficient bioelectronics powered by unconventional micropower may lead to a new generation of implantable, wireless, minimally invasive medical devices, such as pacemakers, defibrillators, drug-delivering pumps, sensor transmitters, and neurostimulators. Studies have shown that micro-enzymatic biofuel cells (EBFCs) are among the most intuitive candidates for in vivo micropower.

In the fisrt part of this thesis, the prototype design of an EBFC chip, having 3D intedigitated microelectrode arrays was proposed to obtain an optimum design of 3D microelectrode arrays for carbon microelectromechanical systems (C-MEMS) based EBFCs. A detailed modeling solving partial differential equations (PDEs) by finite element techniques has been developed …