Nanoscience and Nanotechnology Commons^™

Energy Harvesting Using Photovoltaic And Betavoltaic Devices, Ashish Sharma

Doctoral Dissertations

There is an important need for improvement in both cost and efficiency of photovoltaic cells. For improved efficiency, a better understanding of solar cell performance is required. An analytical model of thin-film silicon solar cell, which can provide an intuitive understanding of the effect of illumination on its charge carriers and electric current, is proposed. The separate cases of homogeneous and inhomogeneous charge carrier generation rates across the device are investigated. This model also provides for the study of the charge carrier transport within the quasi-neutral and depletion regions of the device, which is of an importance for thin-film solar …

Tunable Controlled Release Of Molecular Species From Halloysite Nanotubes, Divya Narayan Elumalai

Doctoral Dissertations

Encouraged by potential applications in rust coatings, self-healing composites, selective delivery of drugs, and catalysis, the transport of molecular species through Halloysite nanotubes (HNTs), specifically the storage and controlled release of these molecules, has attracted strong interest in recent years. HNTs are a naturally occurring biocompatible nanomaterial that are abundantly and readily available. They are alumosilicate based tubular clay nanotubes with an inner lumen of 15 nm and a length of 600-900 nm. The size of the inner lumen of HNTs may be adjusted by etching. The lumen can be loaded with functional agents like antioxidants, anticorrosion agents, flame-retardant agents, …

Manufacturing Polyacrylonitrile Nanowires And Nanofibers For Sensing And Energy Storage Applications, Juan Chen

Doctoral Dissertations

A novel flow guided assembly approach is presented to well align and accurately position nanowire arrays in pre-defined locations with high throughput and large scale manufacturing capability. In this approach, polyacrylonitrile (PAN)/N, N-dimethylformamide (DMF) solution is first filled in an array of microfluidic channels. Then a gas flow is introduced to blow out most solutions while pushing a little leftover against the channel wall to assemble into polymer nanowires. In this way, highly-ordered nanowires are conveniently aligned in the flow direction and patterned along both sides of the microchannels. In this study, we demonstrated this flow-guided assembly process by producing …

Nanoscale Phonon Thermal Conductivity Via Molecular Dynamics, Jonathan M. Dunn

Open Access Theses

Molecular dynamics (MD) simulations provide a useful and simple means of calculating the nanoscale thermal properties of materials, which requires special analysis since the thermal properties of materials change when their dimensions reach the nanoscale. In this research, MD is used to investigate the nanoscale phonon thermal transport of materials that are attracting much interest in the areas of materials science and nuclear physics. In order to evaluate two distinct methods of calculating the thermal conductivity of materials using MD, the simulation methods are first applied to Si. Once an understanding of each simulation method is established, they are then …

Ultra-Thin Boron Nitride Films By Pulsed Laser Deposition: Plasma Diagnostics, Synthesis, And Device Transport, Nicholas Robert Glavin

Open Access Dissertations

This work describes, for the first time, a pulsed laser deposition (PLD) technique for growth of large area, stoichiometric ultra-thin hexagonal and amorphous boron nitride for next generation 2D material electronics. The growth of boron nitride, in this case, is driven by the high kinetic energies and chemical reactivities of the condensing species formed from physical vapor deposition (PVD) processes, which can facilitate growth over large areas and at reduced substrate temperatures. The use of optical emission spectroscopy during plasma growth provides insight into chemistry, kinetic energies, time of flight data, and spatial distributions within a PVD plasma plume ablated …

Design And Testing Of Robotic Capsule Biosensors In The Small Intestine, Zachary Bram

Robotics and Mechanical Systems Design

Biosensors are a tool that is growing in usage and is sought out by doctors and patients alike for being a non-invasive method to monitor health. The data that can be collected from these sensors can be analyzed by doctors that are away from patients, or even by patients that do not have the ability to see a doctor. The purpose of this work is to design and test a biosensor capsule that can attach itself to the inner wall of the small intestine for a short period of time before exiting the body. This research project was a continuation …

Synthesis, Morphological Control, Dispersion Stabilization And In Situ Self-Assembly Of Noble Metal Nanostructures Using Multidentate Resorcinarene Surfactants, Sangbum Han

Chemistry & Biochemistry Theses & Dissertations

In this dissertation, a detailed investigation on the influence of various macrocyclic resorcinarene surfactants in determining the morphology, stabilization and self-assembly of mono- and bi- metallic nanoparticles was undertaken. Chapter 2 describes the influence of resorcinarene surfactants functionalized with amine- and thiol- headgroups in determining the morphology of monometallic Pt nanoparticles synthesized via the Brust-Schiffrin reaction. We found that while resorcinarene benzylthiol can lead to the formation of highly branched Pt nanostructures, resorcinarene amine can lead to the formation of anisotropic crystalline Pt nanoparticles. Further, we have evaluated the influence of resorcinarene ligands in determining the catalytic activity of these …

Forcespinning: A New Method For The Mass Production Of Sn/C Composite Nanofiber Anodes For Lithium Ion Batteries, Victor Agubra, Luis Zuniga, David De La Garza, Luis Gallegos, Madhab Pokhrel, Mataz Alcoutlabi

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

The development of nanostructured anode materials for rechargeable Lithium-ion Batteries has seen a growing interest. We herein report the use of a new scalable technique, Forcespinning (FS) to produce binder-free porous Sn/C composite nanofibers with different Sn particle size loading. The preparation process involves the FS of Sn/PAN precursor nanofibers and subsequently stabilizing in air at 280 °C followed by carbonization at 800 °C under an inert atmosphere. The Sn/C composite nanofibers are highly flexible and were directly used as binder-free anodes for lithium-ion batteries. The produced Sn/C composite nanofibers showed an improved discharge capacity of about 724 mA …

Elastin Like Polypeptides As Drug Delivery Vehicles In Regenerative Medicine Applications, Alex Leonard

USF Tampa Graduate Theses and Dissertations

Elastin like polypeptides (ELPs) are a class of naturally derived biomaterials that are non-immunogenic, genetically encodable, and biocompatible making them ideal for a variety of biomedical applications, ranging from drug delivery to tissue engineering. Also, ELPs undergo temperature-mediated inverse phase transitioning, which allows them to be purified in a relatively simple manner from bacterial expression hosts. Being able to genetically encode ELPs allows for the incorporation of bioactive peptides and functionalization of ELPs. This work utilizes ELPs for regenerative medicine and drug delivery.

The goal of the first study was to synthesize a biologically active epidermal growth factor-ELP (EGF-ELP) fusion …

Electrochemical H2O2 Sensor Based On The Co-Immobilization Of Phosphmolybdic Acid And Graphene On Pedot Film Electrode With Nafion, Hao-Xian Zhou, Jun-Ming Zhang, Zhi-Yu Qu, Pan-Yu Zhang, You-Jun Fan

Journal of Electrochemistry

With a glassy carbon electrode (GCE) as the substrate, the poly(3,4-ethylenedioxythiophene) (PEDOT) film electrode was prepared through the electrochemical polymerization method, then a novel non-enzymatic electrochemical H₂O₂ sensor was fabricated by co-immobilizing phosphomolybdic acid and graphene with Nafion on the PEDOT/GCE electrode. The modified electrodes were characterized by scanning electron microscopy (SEM), while the responsive properties of the sensor to H₂O₂ were investigated by cyclic voltammetry and chronoamperometry. The results demonstrated that, under the optimized conditions, the sensor exhibited good electrocatalytic performance for H₂O₂ reduction. The current response of the sensor …

Adsorption Behavior Of Rhodamine 6g On Silver Surfaces Studied By Electrochemical Surface-Enhanced Raman Spectroscopy, Chan-Juan Chen, Cheng Zong, Guo-Kun Liu, Bin Ren

Journal of Electrochemistry

Rhodamine 6G (R6G) is one of the most common probe molecules employed in single molecule surface-enhanced Raman spectroscopy (SM-SERS). The study in adsorption behavior of R6G will help understand the interactions between R6G and surface. In this paper, we used electrochemical surface-enhanced Raman spectroscopy (SERS) to study the potential-dependent adsorption behavior of R6G on silver electrodes. Our results show that when the potential moved negatively, the orientation of R6G on silver surface changed from vertical to inclined adsorption. This result indicates that the abnormal SM-SERS spectra of R6G observed in the former SM-SERS studies from other research groups are due …

Electrochemical Determination Of Hg(Ii) At Gold Nanoparticles@Carbonaceous Microspheres Modified Electrode, Tian-Yu Qiu, Ming-Chun Wang, Xian-Feng Du, Tian-Jia Jiang, Xing-Jiu Huang

Journal of Electrochemistry

The gold nanoparticles@carbonaceous microspheres (Au@CMSs) and  Au@CMSs modified glassy carbon electrode (GCE) were prepared. The Au@CMSs modified  GCE was further examined for possible sensitive detection of mercury ions (Hg(II)) in an aqueous solution by square wave anodic stripping voltammetry (SWASV). The excellent performance was found in the stripping analysis of Hg(II) in 0.1 mol•L^-1 NaAc-HAc(pH=5.0) with a sensitivity of 25.863 A•(mol•L^-1)^-1 and a detection limit of 3.69×10^-8 mol•L^-1 based on the 3σ method.

Fabrication Of Riboflavin Electrochemical Sensor Based On Au Nanoparticles/Polydopamine/Carbon Nanotubes Modified Glassy Carbon Electrode, Hua-Ping Peng, Mei-Ling Yu, Xin Liu, Pan Liu, Wei Chen, Ai-Lin Liu, Xin-Hua Lin

Journal of Electrochemistry

A novel electrochemical platform for the high sensitivity detection of riboflavin was constructed by Au nanoparticles/polydopamine/carbon nanotubes (Au-PDA-MWCNTs) nanocomposite modified glassy carbon electrode. The Au-PDA-MWCNTs nanocomposite was synthesized by in situ reduction method. The characteristics of the as-prepared Au-PDA-MWCNTs nanocomposite modified electrodes were investigated by using UV-Vis spectroscopy, scanning electron microscopy (SEM) and electrochemical methods. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used to study the electrochemical behavior of riboflavin (RF) at Au-PDA-MWCNTs nanocomposite modified electrodes. The results demonstrated that the present electrochemical sensor exhibited a wide linear range from 5×10^-9 mol•L^-1to 1×10^-5 mol•L …

Thermal Transport Properties Of Dry Spun Carbon Nanotube Sheets, Heath E. Misak, James L. Rutledge, Eric D. Swenson, Shankar Mall

Faculty Publications

The thermal properties of carbon nanotube- (CNT-) sheet were explored and compared to copper in this study. The CNT-sheet was made from dry spinning CNTs into a nonwoven sheet. This nonwoven CNT-sheet has anisotropic properties in in-plane and out-of-plane directions. The in-plane direction has much higher thermal conductivity than the out-of-plane direction. The in-plane thermal conductivity was found by thermal flash analysis, and the out-of-plane thermal conductivity was found by a hot disk method. The thermal irradiative properties were examined and compared to thermal transport theory. The CNT-sheet was heated in the vacuum and the temperature was measured with an …

One-Dimensional Nanostructure And Sensing Applications: Tin Dioxide Nanowires And Carbon Nanotubes, Hoang Anh Tran

Dissertations and Theses

The key challenge for a nanomaterial based sensor is how to synthesize in bulk quantity and fabricate an actual device with insightful understanding of operational mechanisms during performance. I report here effective, controllable methods that exploit the concepts of the "green approach" to synthesize two different one-dimensional nanostructures, including tin oxide nanowires and carbon nanotubes. The syntheses are followed by product characterization and sensing device fabrications as well as sensor performance understanding at the molecular level. Sensor-analyte response and recovery kinetics are also presented.

The first part of the thesis describes bulk-scale synthesis and characterization of tin oxide nanowires by …

Electrodeposition Of High Magnetostrictive Cobalt Iron Alloy Films For Smart Tags And Sensor Applications, Jamin Pillars

Nanoscience and Microsystems ETDs

Magnetostrictive CoFe films were investigated for use as magnetoelastic tags or sensors. The ability to electrodeposit these films enables batch fabrication processes to pattern a variety of geometries while controlling the film stoichiometry and crystallography. In current research looking at CoFe, improved magnetostriction was achieved using a co-sputtering, annealing, and quenching method1. Other current research has reported electrodeposited CoFe films using a sulfate based chemistry resulting in film compositions that are Fe rich in the range of Co0.3-0.4Fe0.7-0.6 and have problems of co-deposition of undesirables that can have a negative impact on magnetic properties2, 3. The research presented here focused …

Method For Hyper-Polarizing Nuclear Spns At Arbtrary Magnetic Felds, Carlos A. Meriles, Daniela Pagliero, Abdelghani Laraoui

Department of Mechanical and Materials Engineering: Faculty Publications

A method of dynamically polarizing the nuclear spin host of nitrogen-vacancy (NV) centers in diamond is provided. The method uses optical, microwave and radio-frequency pulses to recursively transfer spin polarization from the NV electronic spin. Nitrogen nuclear spin initialization approaching 80% at room temperature is demonstrated both in ensemble and single NV centers without relying on level anti-crossings. This makes the method applicable at arbitrary magnetic fields.

Dlvo Approximation Methods For Predicting The Attachment Of Silver Nanoparticles To Ceramic Membranes, Anne M. Mikelonis, Sungmin Youn, Desmond F. Lawler

All Engineering Faculty Research

This article examines the influence of three common stabilizing agents (citrate, poly(vinylpyrrolidone) (PVP), and branched poly(ethylenimine) (BPEI)) on the attachment affinity of silver nanoparticles to ceramic water filters. Citrate-stabilized silver nanoparticles were found to have the highest attachment affinity (under conditions in which the surface potential was of opposite sign to the filter). This work demonstrates that the interaction between the electrical double layers plays a critical role in the attachment of nanoparticles to flat surfaces and, in particular, that predictions of double-layer interactions are sensitive to boundary condition assumptions (constant charge vs constant potential). The experimental deposition results can …

Ferroelectric Characterization And Growth Optimization Of Thermally Evaporated Vinylidene Fluoride Thin Films, Keith Foreman, N. Hong, C. Labedz, C. Shearer, Stephen Ducharme, Shireen Adenwalla

Shireen Adenwalla Papers

Organic thin films have numerous advantages over inorganics in device processing and price. The large polarization of the organic ferroelectric oligomer vinylidene fluoride (VDF) could prove useful for both device applications and the investigation of fundamental physical phenomena. A VDF oligomer thin film vacuum deposition process, such as thermal evaporation, preserves film and interface cleanliness, but is challenging, with successful deposition occurring only within a narrow parameter space. We report on the optimal deposition parameters for VDF oligomer thin films, refining the parameter space for successful deposition, resulting in a high yield of robust ferroelectric films. In particular, we investigate …

Optimization Of Transition-Metal Dichalcogenides Based Field- Effect- Transistors Via Contact Engineering, Meeghage Madusanka Perera

Wayne State University Dissertations

ABSTRACT

Optimization of Transition-Metal Dichalcogenides based Field- Effect-Transistors via contact engineering

by

Meeghage M Perera

September , 2016

Advisor : Dr. Zhixian Zhou

Major: Physics (Condensed mater physics/nano-electronics)

Degree: Doctor of Philosophy

Layered transition Metal Dichalcogenides (TMDs) have demonstrated a wide range of remarkable properties for applications in next generation nano-electronics. These systems have displayed many “graphene-like” properties including a relatively high carrier mobility, mechanical flexibility, chemical and thermal stability, and moreover offer the significant advantage of a substantial band gap. However, the fabrication of high performance field-effect transistors (FETs) of TMDs is challenging mainly due to the formation of …