Nanoscience and Nanotechnology Commons^™

Straintronic Nanomagnetic Devices For Non-Boolean Computing, Md Ahsanul Abeed

Theses and Dissertations

Nanomagnetic devices have been projected as an alternative to transistor-based switching devices due to their non-volatility and potentially superior energy-efficiency. The energy efficiency is enhanced by the use of straintronics which involves the application of a voltage to a piezoelectric layer to generate a strain which is ultimately transferred to an elastically coupled magnetostrictive nanomaget, causing magnetization rotation. The low energy dissipation and non-volatility characteristics make straintronic nanomagnets very attractive for both Boolean and non-Boolean computing applications. There was relatively little research on straintronic switching in devices built with real nanomagnets that invariably have defects and imperfections, or their adaptation …

Fabrication And Characterization Of Nanofiber Nylon-6-Mwcnt As An Electrochemical Sensor For Sodium Ions Concentration Detection In Sweat, Kelsey Mills

Williams Honors College, Honors Research Projects

Fabrication and characterization nylon-6-MWCNT nanofiber as an electrochemical sensor to detect sodium ion concentrations specifically in sweat. Using contact angle to determine surface morphology and chronoamperometry testing to identify ideal sensor conditions, tests optimized parameters like weight percent of nylon or other polymers, carbon nanotube (CNT) isomer, and solution concentration to determine reproducibility of functional sensors. Utilizing the electric qualities of carbon nanotubes partnered with the sodium ion selectivity of calixarene treatment and polymers unique properties like flexibility and scalability create open an arena for optimizing sodium ion sensors for further development for functional prototypes. Morphology tests showed that the …

Resonant Acoustic Wave Assisted Spin-Transfer-Torque Switching Of Nanomagnets, Austin R. Roe

Theses and Dissertations

We studied the possibility of achieving an order of magnitude reduction in the energy dissipation needed to write bits in perpendicular magnetic tunnel junctions (p-MTJs) by simulating the magnetization dynamics under a combination of resonant surface acoustic waves (r-SAW) and spin-transfer-torque (STT). The magnetization dynamics were simulated using the Landau-Lifshitz-Gilbert equation under macrospin assumption with the inclusion of thermal noise. We studied such r-SAW assisted STT switching of nanomagnets for both in-plane elliptical and circular perpendicular magnetic anisotropy (PMA) nanomagnets and show that while thermal noise affects switching probability in in-plane nanomagnets, the PMA nanomagnets are relatively robust to the …

Engineering Plasmonic Nanostructures For Light Management And Sensing, Sujan Phani Kumar Kasani

Graduate Theses, Dissertations, and Problem Reports (ETD)

The two major global problems are to provide health safety and to meet energy demands for ever growing population on a large scale. The study of light interaction with nanostructures has shown a promising solution in improving the fields of bio-sensor and solar energy devices which addresses above mentioned two major global problems. Nanostructures have tunable physicochemical properties such as light absorption, electrical and thermal properties unlike bulk materials, which gives an advantage in applications like bio-sensing and energy harvesting devices. The development of nanofabrication techniques along with the discovery of Surface Enhanced Raman Scattering (SERS) and Plasmon Enhanced Fluorescence …

The Pilot Application Of Electrochemical Impedance Spectroscopy On Dynamic Proton Exchange Membrane Fuel Cell, Jian-Wei Guo, Jian-Long Wang

Journal of Electrochemistry

By analyzing Electrochemical Impedance Spectroscopy (EIS) in applications of dynamic proton exchange membrane fuel cell (PEMFC), bottlenecks which restrict EIS tool development have been pointed out in this paper. Though the high-frequency resistance in EIS is largely accepted as cell inner-resistance, this can only be applied for cell with low current. The low-frequency resistance is difficult to be realized due to its relation with mass transfer. Furthermore, the improved Randles equivalent circuits are built up preliminarily, thus, penetrating into studies for mass transfer reaction, cell operation/degeneration, and high temperature fuel cell. Inspiringly, EIS is becoming an analyzing tool for stack …

Caging Porous Co-N-C Nanocomposites In 3d Graphene As Active And Aggregation-Resistant Electrocatalyst For Oxygen Reduction Reaction, Lu-Yang Xiu, Meng-Zhou Yu, Peng-Ju Yang, Zhi-Yu Wang, Jie-Shan Qiu

Journal of Electrochemistry

Oxygen reduction reaction (ORR) is the cornerstone reaction of many renewable energy technologies such as fuel cells and rechargeable metal-air batteries. The Pt-based electrocatalysts exhibit the highest activity toward ORR, but their large implementation is greatly prohibiting by unaffordable cost and inferior durability. During electrode manufacturing and electrochemical reaction, severe aggregation of catalyst nanoparticles induced by size effect further limits the operational performance of electrocatalysts. We report a new strategy for fabrication of active and aggregation-resistant ORR electrocatalyst by caging metal-organic frameworks derived Co-N-C nanocomposites in permeable and porous 3D graphene cages via sprayed drying the mixed colloids of ZIF-67 …

Palladium Adatoms On Gold Nanoparticles As Electrocatalysts For Ethanol Electro-Oxidation In Alkaline Solutions, Hui-Mei Chen, Shang-Qian Zhu, Jia-Le Huang, Min-Hua Shao

Journal of Electrochemistry

Palladium (Pd) is a good catalyst for ethanol electro-oxidation in alkaline solutions. The activity of Pd is further improved in this study by modifying the gold (Au) nanoparticles with Pd adatoms using a simple spontaneous deposition process. The Pd overlayer on the Au core (Au@Pd) is un-uniform with some Au atoms exposed to the electrolyte. The activity of Au@Pd/C toward ethanol oxidation reaction (EOR) is much higher than that of Pd/C in an alkaline solution. The peak current density of Au@Pd/C is 4.6 times higher than that of Pd/C with a 100 mV lower onset potential. The enhanced activity may …

Fe-N Doped Hollow Carbon Nanospheres Linked By Carbon Nanotubes For Oxygen Reduction Reaction, Ya-Lin Zhang, Chi Chen, Liang-Liang Zou, Zhi-Qing Zou, Hui Yang

Journal of Electrochemistry

The development of non-precious metal catalysts for oxygen reduction reaction (ORR) is essential for large-scale application of proton exchange membrane fuel cells. Herein, we present the in situ formed Fe-N doped hollow carbon nanospheres linked by carbon nanotubes composite, synthesized by using ZIF-8 as sacrificed template to form polydopamine (PDA) hollow nanospheres, followed by complexing with FeCl₃, high temperature heat-treatment and NH₃-etching. ZIF-8 was gradually decomposed simultaneously with PDA coating due to the loss of Zn²⁺ grabbed by PDA. NH3 etching resulted in the improved surface area, while the reducibility of NH₃ resulted in …

Facile Synthesis Of Pt-Cu Alloy Nanodendrites As High-Performance Electrocatalysts For Oxygen Reduction Reaction, Liu-Xuan Luo, Guang-Hua Wei, Shui-Yun Shen, Feng-Juan Zhu, Chang-Chun Ke, Xiao-Hui Yan, Jun-Liang Zhang

Journal of Electrochemistry

Structures and compositions have significant effects on the catalytic properties of nanomaterials. Herein, a facile etching-based method was employed to synthesize Pt-Cu nanodendrites (NDs) with uniform and homogeneous alloy structures for enhancing oxygen reduction reaction (ORR). The formation of dendritic morphology was ascribed to the etching effect caused by the oxidative etchants of the Br^-/O₂ pair. The atomic ratio of Pt/Cu in Pt-Cu NDs could be easily tuned by altering the ratio of the Pt/Cu precursors, without deteriorating the dendritic morphology. The most active carbon-supported Pt₁Cu₁ NDs (Pt₁Cu₁ NDs/C) exhibited the …

Exploration Of Radiation Damage Mechanism In Mems Devices., Pranoy Deb Shuvra

Electronic Theses and Dissertations

We explored UV, X-ray and proton radiation damage mechanisms in MEMS resonators. T-shaped MEMS resonators of different dimensions were used to investigate the effect of radiation. Radiation damage is observed in the form of resistance and resonance frequency shift of the device. The resistance change indicates a change in free carrier concentration and mobility, while the resonance frequency change indicates a change in mass and/or elastic constant. For 255nm UV radiation, we observed a persistent photoconductivity that lasts for about 60 hours after radiation is turned off. The resonance frequency also decreases 40-90 ppm during irradiation and slowly recovers at …

Optimizing The Plasmonic Enhancement Of Light In Metallic Nanogap Structures For Surface-Enhanced Raman Spectroscopy, Stephen Joseph Bauman

Graduate Theses and Dissertations

Technology based on the interaction between light and matter has entered something of a renaissance over the past few decades due to improved control over the creation of nanoscale patterns. Tunable nanofabrication has benefitted optical sensing, by which light is used to detect the presence or quantity of various substances. Through methods such as Raman spectroscopy, the optical spectra of solid, liquid, or gaseous samples act as fingerprints which help identify a single type of molecule amongst a background of potentially many other chemicals. This technique therefore offers great benefit to applications such as biomedical sensors, airport security, industrial waste …

Gesn Thin Film Epitaxy And Quantum Wells For Optoelectronic Devices, Perry Christian Grant

Graduate Theses and Dissertations

Group IV photonics is an effort to generate viable infrared optoelectronic devices using group IV materials. Si-based optoelectronics have received monumental research since Si is the heart of the electronics industry propelling our data driven world. Silicon however, is an indirect material whose optical characteristics are poor compared to other III-IV semiconductors that make up the optoelectronics industry. There have been major efforts to integrate III-V materials onto Si substrates. Great progress on the integration of these III-V materials has occurred but incompatibility with CMOS processing has presented great difficulty in this process becoming a viable and cost-effective solution. Germanium …

Physical Electronic Properties Of Self-Assembled 2d And 3d Surface Mounted Metal-Organic Frameworks, Radwan Elzein

USF Tampa Graduate Theses and Dissertations

Metal-organic frameworks stand at the frontiers of molecular electronic research because they combine desirable physical properties of organic and inorganic components. They are crystalline porous solids constructed by inorganic nodes coordinated to organic ligands to form 1D, 2D, or 3D structures. They possess unique characteristics such as ultrahigh surface area crystal lattices up to 10000 m² g^-1, and tunable nanoporous sizes ranging from 0.2 to 50 nm. Their unprecedented structural diversity and flexibility beyond solid state materials can lead to unique properties such as tailorable electronic and ionic conductivity which can serve as interesting platforms for a …

Recent Advances In Non-Noble Metal Nanomaterials For Oxygen Evolution Electrocatalysis, Dan-Dan Zhao, Nan Zhang, Ling-Zheng Bu, Qi Shao, Xiao-Qing Huang

Journal of Electrochemistry

Hydrogen is a kind of renewable energies with the merits of environmentally friendly, abundance and high weight energy density, which can replace the fossil energy. The electrolysis of water is regarded as the most effective way to generate hydrogen. Owing to the sluggish kinetics and large overpotential of the anode oxygen evolution reaction (OER), the efficiency of the cathode hydrogen evolution reaction is greatly limited. Therefore, it is highly desirable to explore efficient, stable and low cost electrocatalysts to reduce the overpotential of OER and improve the efficiency of hydrogen evolution. Based on the natural characteristics of non-noble metal catalysts …

Hyperspectral Imaging For Characterizing Single Plasmonic Nanostructure And Single-Cell Analysis, Nishir Sanatkumar Mehta

LSU Master's Theses

Orientation of plasmonic nanostructures is an important feature in many nanoscale applications such as photovoltaics, catalyst, biosensors DNA interactions, protein detections, hotspot of surface-enhanced Raman spectroscopy (SERS), and fluorescence resonant energy transfer (FRET) experiments. Silver nanocubes with significant spectral signatures between 400-700 nm are observed in this experimental research. Whereas study of single cells will enable the analysis of cell-to-cell variations within a heterogeneous population. These variations are important for further analysis and understanding of disease propagation, drug development, stem cell differentiation, embryos development, and how cells respond to each other and their environment. Adipose-derived mesenchymal stem cells possess the …

No2- And No3- Enhance Cold Atmospheric Plasma Induced Cancer Cell Death By Generation Of Onoo-, Dehui Xu, Qingjie Cui, Yujing Xu, Zhijie Liu, Zeyu Chen, Wenjie Xia, Hao Zhang, Dingxin Liu, Hailan Chen, Michael G. Kong

Bioelectrics Publications

Cold atmospheric plasma (CAP) is a rapidly developed technology that has been widely applied in biomedicine especially in cancer treatment. Due to the generation of various active species in plasma, CAP could induce various tumor cells death and showed a promising potential in cancer therapy. To enhance the biological effects of gas plasma, changing the discharging parameters is the most commonly used method, yet increasing discharging power will lead to a higher possibility of simultaneously damage surrounding tissues. In this study, by adding nontoxic concentration of additional nitrite and nitrate in the medium, we found that anti-tumor effect of CAP …

Complex Coordination Silver Electrocrystallization Mechanism On Glassy Carbon Electrode Surface, Shuai-Shuai Huang, Cheng Liu, Lei Jin, Fang-Zu Yang, Zhong-Qun Tian, Shao-Min. Zhou

Journal of Electrochemistry

Cyclic voltammetry and potential step methods were successfully used to study the electrochemical crystallization mechanism of silver deposition on glassy carbon electrode (GCE) in the practical cyanide-free silver plating electrolyte containing composite complexing agents. Scharifker-Hill (SH) theory was used to fitting the experimental data. The results showed that the electrodeposition of silver is a diffusion controlled irreversible electrode process according to three-dimensional instantaneous nucleation mechanism. When the step potential shifted from -750 mV to -825 mV, the peak deposition current Im was increased, while the induced nucleation time tm shortened. The calculated kinetic parameters showed that the diffusion coefficient (D) …

Highly Crystalline Nickel Borate Nanorods As Oxygen Evolution Reaction Electrocatalysts, Xi Xu, Juan Liu, Hua-Zong Wu, Wen-Jie Jiang

Journal of Electrochemistry

Hydrogen energy, a kind of clean and renewable energy, is considered to be the solution to the problems of energy crisis and environmental deterioration. Electrochemical water splitting is an efficient and promising technology for the production of high-purity hydrogen. However, oxygen evolution reaction (OER) at the anode of water electrolyzer limits the efficiency of water splitting due to the high overpotential. Therefore, the challenges still remain for the exploration of highly active, stable and low-cost catalysts with superior activity for OER. Herein, nickel borate nanorods with high crystallinity were prepared via high-temperature calcination. The as-obtained nickel borate nanorods with 2 …

Spice Based Compact Model For Electrical Switching Of Antiferromagnet, Xe Jin Chan, Jan Kaiser, Pramey Upadhyaya

The Summer Undergraduate Research Fellowship (SURF) Symposium

A simulation framework that can model the behavior of antiferromagnets (AFMs) is essential to building novel high-speed devices. The electrical switching of AFMs allows for high performance memory applications. With new phenomena in spintronics being discovered, there is a need for flexible and expandable models. With that in mind, we developed a model for AFMs which can be used to simulate AFM switching behavior in SPICE. This approach can be modified for adding modules, keeping pace with new developments. The proposed AFM switching model is based on the Landau-Lifshitz-Gilbert equation (LLG). LLG along with an exchange coupling module is implemented …

Opto-Thermal Characterization Of Plasmon And Coupled Lattice Resonances In 2-D Metamaterial Arrays, Vinith Bejugam

Graduate Theses and Dissertations

Growing population and climate change inevitably requires longstanding dependency on sustainable sources of energy that are conducive to ecological balance, economies of scale and reduction of waste heat. Plasmonic-photonic systems are at the forefront of offering a promising path towards efficient light harvesting for enhanced optoelectronics, sensing, and chemical separations. Two-dimensional (2-D) metamaterial arrays of plasmonic nanoparticles arranged in polymer lattices developed herein support thermoplasmonic heating at off-resonances (near infrared, NIR) in addition to regular plasmonic resonances (visible), which extends their applicability compared to random dispersions. Especially, thermal responses of 2-D arrays at coupled lattice resonance (CLR) wavelengths were comparable …

Pt/G-C3N4 Nanosheet For Visible Light-Induced Enhancement Of The Activity For Formic Acid Electro-Oxidation, Yong-Rong Sun, Chun-Yu Du, Guo-Kang Han, Ya-Jing Wang, Yun-Zhi Gao, Ge-Ping Yin

Journal of Electrochemistry

By using graphitic carbon nitride nanosheet (g-C₃N₄ nanosheet) as a support,Pt/g-C₃N₄ nanosheet catalyst was fabricated by microwave assisted polylol process. The nanoparticles size,composition,structure and optical properties of Pt/g-C₃N₄ nanosheet were characterized by TEM,XRD,XPS and UV-Vis diffuse reflectance spectroscopy. Comparing with the catalytic activities toward formic acid electro-oxidation under dark and visible light illumination,the superior activity of Pt/g-C₃N₄ nanosheet catalyst was achieved under visible light illumination. This visible light-driven enhancement in the formic acid performance could be attributed to the plasmon-induced electron-hole separation on g-C₃N₄ with …

Carbon Composite Fe3O4 Nanoparticles Based Electrochemical Sensor For Hydrogen Peroxide Detection, Si-Yu Zhang, Hui-Juan Wang, Shu-Fang Li, Jian-Ying Qu

Journal of Electrochemistry

In this work, a novel hydrogen peroxide electrochemical sensor was constructed with ferroferric oxide (Fe₃O₄) magnetic nanoparticles, which demonstrated good electrocatalytic activity for hydrogen peroxide. There existed a good linear relationship between the concentration of hydrogen peroxide and the oxidation peak current in the range of 1.00 × 10^-6 ~ 1.00 × 10^-3 mol·L^-1 (R = 0.9980) with the detection limit of 6.60 × 10-7 mol·L^-1. The sensor exhibited good anti-interference ability, high reproducibility and stability.

Lead Modified Nanoporous Platinum Electro-Catalysts For Formic Acid Oxidation, Yuan-Yuan Zhang, Qing-Feng Yi, Ge-Kun-Kun Zuo, Tao Zou, Xiao-Ping Liu, Xiu-Lin Zhou

Journal of Electrochemistry

Platinum (Pt) catalysts modified by other suitable metals significantly enhance their electrochemical activities for formic acid oxidation. In this work, a titanium-supported nanoporous network platinum (nanoPt/Ti) electrode was prepared using a hydrothermal method. The as-prepared nanoPt/Ti electrode was modified with a certain amount of lead by using cyclic voltammetry for different scan cycle numbers (n), namely, n = 10, 15, 20 and 30, to synthesize the novel lead-modified nanoporous Pt (nanoPb_(n)-Pt/Ti) electrodes. Electro-oxidation of formic acid on these electrodes was studied with cyclic voltammetry (CV), chronoamperometry and chronopotentiometry in sulfuric acid solution. CV curves showed that both nanoPt/Ti …

Voltage-Controlled Deposition Of Nanoparticles For Next Generation Electronic Materials, Subhodip Maulik

LSU Doctoral Dissertations

This work presents both a feasibility study and an investigation into the voltage-controlled spray deposition of different nanoparticles, namely, carbon nanotubes (CNTs), as well as molybdenum disulfide (MoS₂) and tungsten disulfide (WS₂) from the transition metal dichalcogenides (TMDCs) family of materials. The study considers five different types of substrates as per their potential application to next-generation device electronics. The substrates selected for this research were: 1) aluminum as a conducting substrate, 2) silicon as a semiconducting substrate, 3) glass, silicon dioxide (SiO₂), and syndiotactic poly methyl methacrylate (syndiotactic PMMA) as insulating substrates.

Since the …

Glucose Level Estimation Based On Invasive Electrochemical, And Non-Invasive Optical Sensing Methods, Sanghamitra Mandal

Graduate Theses and Dissertations

The purpose of this research is to design and fabricate sensors for glucose detection using inexpensive approaches. My first research approach is the fabrication of an amperometric electrochemical glucose sensor, by exploiting the optical properties of semiconductors and structural properties of nanostructures, to enhance the sensor sensitivity and response time. Enzymatic electrochemical sensors are fabricated using two different mechanisms: (1) the low-temperature hydrothermal synthesis of zinc oxide nanorods, and (2) the rapid metal-assisted chemical etching of silicon (Si) to synthesize Si nanowires. The concept of gold nano-electrode ensembles is then employed to the sensors in order to boost the current …

Design, Fabrication, And Characterization Of All-Inorganic Quantum Dot Light Emitting Diodes, Ramesh Vasan

Graduate Theses and Dissertations

Quantum dot light emitting diodes are investigated as a replacement to the existing organic light emitting diodes that are commonly used for thin film lighting and display applications. In this, all-inorganic quantum dot light emitting diodes with inorganic quantum dot emissive layer and inorganic charge transport layers are designed, fabricated, and characterized. Inorganic materials are more environmentally stable and can handle higher current densities than organic materials. The device consists of CdSe/ZnS alloyed core/shell quantum dots as the emissive layer and metal oxide charge transport layer. The charge transport in these devices is found to occur through resonant energy transfer …

Advancing The Understanding Of Environmental Transformations, Bioavailability And Effects Of Nanomaterials, An International Us Environmental Protection Agency—Uk Environmental Nanoscience Initiative Joint Program, Mitch M. Lasat, Kian Fan Chung, Jamie Lead, Steve Mcgrath, Richard J. Owen, Sophie Rocks, Jason M. Unrine, Junfeng Zhang

Plant and Soil Sciences Faculty Publications

Nanotechnology has significant economic, health, and environmental benefits, including renewable energy and innovative environmental solutions. Manufactured nanoparticles have been incorporated into new materials and products because of their novel or enhanced properties. These very same properties also have prompted concerns about the potential environmental and human health hazard and risk posed by the manufactured nanomaterials. Appropriate risk management responses require the development of models capable of predicting the environmental and human health effects of the nanomaterials. Development of predictive models has been hampered by a lack of information concerning the environmental fate, behavior and effects of manufactured nanoparticles. The United …

Plasmonic Structures For Subwavelength Guiding And Enhanced Light-Matter Interactions, Amirreza Mahigir

LSU Doctoral Dissertations

In this dissertation we design and analyze nanostructures for subwavelength guiding and enhanced light-matter interactions.

We first investigate three-dimensional plasmonic waveguide-cavity structures, built by side-coupling stub resonators that consist of plasmonic coaxial waveguides of finite length, to a plasmonic coaxial waveguide. These structures are capable of guiding and manipulating light in deep-subwavelength volumes. We show that three-dimensional plasmonic coaxial waveguides offer a platform for practical realization of deep-subwavelength optical waveguides.

We then introduce compact wavelength-scale slit-based structures for coupling free space light into the fundamental mode of plasmonic coaxial waveguides. We consider single-, double-, and triple-slit structures optimized at the …

Preparation And Properties Of Nanocrystalline Nickel By Pulse Electrodeposition On Glassy Carbon, Ya-Li Zhang, Ming-Xian Zhang, Teng-Da Guo, Yan-Jie Zhao, Sheng-Xue Yu

Journal of Electrochemistry

Nanocrystalline nickel exhibits electrocatalytic activity for methanol. In this work, nanocrystalline nickel coating has been obtained by using the double pulse method on glassy carbon materials surface. The influence of pulse conditions on the grain size of nanocrystalline nicke was studied. The concentrations and compositions of the plating bath were  300 g·L^-1 NiSO₄·6H₂O,45 g·L^-1 NiCl₂·6H₂O,40 g·L^-1 H₃BO₃,5 g·L^-1 C₇H₅NO₃S,and 0.05 g·L^-1 C₁₂H₂₅NaO₄S. The optimal pulse process parameters including the average pulse …

Hydrophobic Surface Modification Of Polymethyl Methacrylate By Two-Dimensional Plasma Jet Array At Atmospheric Pressure, Feng Liu, Meiling Cai, Bo Zhang, Zhi Fang, Chunqi Jiang, Kostya Ken Ostrikov

Bioelectrics Publications

Recently developed atmospheric pressure plasma jet (APPJ) is considered as a novel and efficient technique for uneven surfaces processing and APPJ array effectively expands the treatment area of a single APPJ. In this paper, a two-dimensional (2D) APPJ array in Ar/tetramethylsilane (TMS) is used to improve the surface hydrophobicity of polymethyl methacrylate (PMMA) by depositing polymerized silicalike clusters on the jet-PMMA interface. The electrical and optical characteristics of the 2D Ar/TMS APPJ array are measured to optimize experimental conditions. The wettability of jet-PMMA interface is assessed by measuring water contact angle, which increases from 65° to a maximum value of …