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Materials Science and Engineering

2020

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Articles 1 - 30 of 40

Full-Text Articles in Nanoscience and Nanotechnology

Treated Hfo2 Based Rram Devices With Ru, Tan, Tin As Top Electrode For In-Memory Computing Hardware, Yuvraj Dineshkumar Patel Dec 2020

Treated Hfo2 Based Rram Devices With Ru, Tan, Tin As Top Electrode For In-Memory Computing Hardware, Yuvraj Dineshkumar Patel

Theses

The scalability and power efficiency of the conventional CMOS technology is steadily coming to a halt due to increasing problems and challenges in fabrication technology. Many non-volatile memory devices have emerged recently to meet the scaling challenges. Memory devices such as RRAMs or ReRAM (Resistive Random-Access Memory) have proved to be a promising candidate for analog in memory computing applications related to inference and learning in artificial intelligence. A RRAM cell has a MIM (Metal insulator metal) structure that exhibits reversible resistive switching on application of positive or negative voltage. But detailed studies on the power consumption, repeatability and retention …

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Core-Shell Structured Ru@Ptru Nanoflower Electrocatalysts Toward Alkaline Hydrogen Evolution Reaction, Xue-Liang Wang, Yuan-Yuan Cong, Chen-Xi Qiu, Sheng-Jie Wang, Jia-Qi Qin, Yu-Jiang Song Dec 2020

Core-Shell Structured Ru@Ptru Nanoflower Electrocatalysts Toward Alkaline Hydrogen Evolution Reaction, Xue-Liang Wang, Yuan-Yuan Cong, Chen-Xi Qiu, Sheng-Jie Wang, Jia-Qi Qin, Yu-Jiang Song

Journal of Electrochemistry

Water electrolysis for hydrogen production is beneficial for solving the problem of energy crisis and environmental issues. It is necessary to study highly active and cost-effective catalysts toward hydrogen evolution reaction (HER) to reduce the consumption of noble metals. Herein, we report the synthesis of core-shell structured Ru@Pt0.24Ru nanoflowers electrocatalyst by stepwise reduction of Ru and Pt precursors in the mixture of oleylamine and benzyl alcohol at 160 oC. The average diameter of the resultant Ru@Pt0.24Ru was 16.5±4.0 nm with a bulk atomic ratio between Pt and Ru of 0.24:1 and a surface ratio of 3.3:1 …

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Preparations And Photoelectrochemical Performances Of Rgo-Tio2 Nanotubes Arrays, Ze-Yang Zhang, Lan Sun, Chang-Jian Lin Dec 2020

Preparations And Photoelectrochemical Performances Of Rgo-Tio2 Nanotubes Arrays, Ze-Yang Zhang, Lan Sun, Chang-Jian Lin

Journal of Electrochemistry

Decorating TiO2 nanotube arrays with RGO to improve the photocatalytic activity of TiO2 nanotube arrays has been reported. For the reported RGO-TiO2 nanotube arrays, TiO2 nanotube arrays were prepared by anodizing the high-purity Ti foil in an organic electrolyte for multiple-step treatments, while RGO were deposited on TiO2 nanotube arrays by using cyclic voltammetry or other electrical reduction methods. To enhance the reduction degree and the coverage of RGO on the resultant RGO-TiO2 nanotube arrays, in this work, the one-step electrochemical anodization in hydrofluoric acid was used to fabricate TiO2 nanotube arrays with …

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Interface Engineering Of Materials For Energy And Biological Applications, Ardalan Chaichi Dec 2020

Interface Engineering Of Materials For Energy And Biological Applications, Ardalan Chaichi

LSU Doctoral Dissertations

Interface interactions are generally classified into solid-liquid, solid-gas, solid-vacuum, liquid-gas, light-matter and electron-matter categories. Surface morphological studies as well as surface chemical reactions can be studied in various types of complex systems thanks to technological advances in materials characterization methods. By employing interface engineering in different applications, it is possible to control electrical, chemical, mechanical, optical and biological properties of materials. Accordingly, we have applied interface engineering in three different areas of energy materials, biomaterials and surface imaging. As a result, firstly, we have introduced a high intensity light flash-based method on engineered substrates for delamination of reduced graphene oxide …

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3-D Fabry–Pérot Cavities Sculpted On Fiber Tips Using A Multiphoton Polymerization Process, Jonathan W. Smith, Jeremiah C. Williams, Joseph S. Suelzer, Nicholas G. Usechak, Hengky Chandrahalim Dec 2020

3-D Fabry–Pérot Cavities Sculpted On Fiber Tips Using A Multiphoton Polymerization Process, Jonathan W. Smith, Jeremiah C. Williams, Joseph S. Suelzer, Nicholas G. Usechak, Hengky Chandrahalim

Faculty Publications

This paper presents 3-D Fabry–Pérot (FP) cavities fabricated directly onto cleaved ends of low-loss optical fibers by a two-photon polymerization (2PP) process. This fabrication technique is quick, simple, and inexpensive compared to planar microfabrication processes, which enables rapid prototyping and the ability to adapt to new requirements. These devices also utilize true 3-D design freedom, facilitating the realization of microscale optical elements with challenging geometries. Three different device types were fabricated and evaluated: an unreleased single-cavity device, a released dual-cavity device, and a released hemispherical mirror dual-cavity device. Each iteration improved the quality of the FP cavity's reflection spectrum. The …

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Synthesis Of Novel Coo/Mnfe2o4 Heterostructured Nanoparticles And The Effects Of Variable Size And Extent Of Overgrowth On Their Magnetic Properties, Mohammad Tauhidul Islam Dec 2020

Synthesis Of Novel Coo/Mnfe2o4 Heterostructured Nanoparticles And The Effects Of Variable Size And Extent Of Overgrowth On Their Magnetic Properties, Mohammad Tauhidul Islam

MSU Graduate Theses

A combination of thermal decomposition and surfactant-assisted synthesis route was utilized to synthesize novel CoO/MnFe2O4 heterostructured nanoparticles. Four samples of varying CoO core size were synthesized with variable extent of overgrowth phase. XRD, XPS, SEM and TEM data show evidence of MnFe2O4 spinel phase overgrowth on CoO rock-salt structured nanoparticles. XPS and magnetic data reveal partial oxidation and formation of Co3O4 phase on 7 nm and 19 nm size CoO-based nanoparticles. The remaining samples having 22 nm and 34 nm dimensions show a higher percentage of FiM materials overgrowth on the …

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Kinetic Monte Carlo Investigations Involving Atomic Layer Deposition Of Metal-Oxide Thinfilms, David Tyler Magness Dec 2020

Kinetic Monte Carlo Investigations Involving Atomic Layer Deposition Of Metal-Oxide Thinfilms, David Tyler Magness

MSU Graduate Theses

Atomic Layer Deposition is a method of manufacturing thin film materials. Metal-oxides such as zinc-oxide and aluminum-oxide are particularly interesting candidates for use in microelectronic devices such as tunnel junction barriers, transistors, Schottky diodes, and more. By adopting a 3D Kinetic Monte Carlo model capable of simulating ZnO deposition, the effect of parameters including deposition temperature, chamber pressure, and composition of the initial substrate at the beginning of deposition can be investigated. This code generates two random numbers: One is used to select a chemical reaction to occur from a list of all possible reactions and the second is used …

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Anisotropic Cuinse2 Nanocrystals: Synthesis, Optical Properties And Their Effect On Photoelectric Response Of Dye-Sensitized Solar Cell, Ahmed Mysara, M Mohsen Abdelaziz, A N. Emam, A S. Mansour, A A. F. Zikry, M .B Mohamed, Y H. Elbashar Nov 2020

Anisotropic Cuinse2 Nanocrystals: Synthesis, Optical Properties And Their Effect On Photoelectric Response Of Dye-Sensitized Solar Cell, Ahmed Mysara, M Mohsen Abdelaziz, A N. Emam, A S. Mansour, A A. F. Zikry, M .B Mohamed, Y H. Elbashar

Nanotechnology Research Centre

CuInSe2 I-III-VI2 ternary is a semiconductor considered very good efficient solar energy conversion material. An organometallic pyrolysis method is used to prepare monodisperse CuInSe2 nanoparticles using a mixture of oleylamine, and trioctylphosphine, as capping materials. The particle shape changes to dot, rods or flowers occur via varying the reaction temperatures (160, 200, 220±C) respectively. The obtained particles have been characterized to determine the shape and size of CuInSe2 nanoparticles using HR-TEM and XRD. The optical and electronic properties of these particles have been investigated and discussed in detail. Then the different shapes of CuInSe …

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Electrochemical Engineering Of Carbon Nanodots, Lei Bao, Dai-Wen Pang Oct 2020

Electrochemical Engineering Of Carbon Nanodots, Lei Bao, Dai-Wen Pang

Journal of Electrochemistry

Carbon nanodots (CNDs), as zero-dimensional carbonaceous fluorescent nanomaterials, are valuable add-ons to the current cohorts of fluorescent nanoparticles. The fine control over the size and the surface is the key to gain designated photophysical properties of CNDs as well as empowers CNDs in many applications. Herein, a series of electrochemical strategies to manipulate the size and the surface of CNDs and to identify the surface structures was presented. Accordingly, the understandings on the originals of photoluminescence as well as the pathways of electrochemiluminescence of CNDs were revealed. These studies demonstrated that electrochemical methods were easy to operate, cost-effective and efficient …

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Development Of Zeolitic Imidazolate Frameworks For Enhancing Post-Combustion Co2 Capture, Dustin Lee Sep 2020

Development Of Zeolitic Imidazolate Frameworks For Enhancing Post-Combustion Co2 Capture, Dustin Lee

Master's Theses

Post-combustion CO2 capture is a promising approach for complementing other strategies to mitigate climate change. Liquid absorption is currently used to capture CO2 from post-combustion flue gases. However, the high energy cost required to regenerate the liquid absorbents is a major drawback for this process. As a result, solid sorbents have been investigated extensively in recent years as alternative media to capture CO2 from flue gases. For example, metal organic frameworks (MOFs) are nanoporous materials that have high surface areas, large pore volumes, and flexible designs. A large number of MOFs, however, suffer from 1) low CO …

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Recent Progress On Enhancing Effect Of Nanosized Metals For Electrochemical Co2 Reduction, Yu-Ning Zhang, Dong-Fang Niu, Shuo-Zhen Hu, Xin-Sheng Zhang Aug 2020

Recent Progress On Enhancing Effect Of Nanosized Metals For Electrochemical Co2 Reduction, Yu-Ning Zhang, Dong-Fang Niu, Shuo-Zhen Hu, Xin-Sheng Zhang

Journal of Electrochemistry

The electrochemical conversion of CO2 to chemical raw material for further utilization shows promising future to alleviate global warming and realize carbon cycle in nature, which is of great significance to the green chemistry and sustainable development. This review briefly introduces the advantages of CO2 electrochemical reduction (CO2ER) and its basic reaction principles, and summarizes the recent progress in a series of activity enhancement strategies based on nanosized metal catalysts. The influences of alloy effect, interface engineering, synergistic effect, surface defect engineering and support effect on the catalytic performance of nanosized metals for CO2ER …

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Research Progresses Of Copper Interconnection In Chips, Lei Jin, Jia-Qiang Yang, Fang-Zu Yang, Dong-Ping Zhan, Zhong-Qun Tian, Shao-Min Zhou Aug 2020

Research Progresses Of Copper Interconnection In Chips, Lei Jin, Jia-Qiang Yang, Fang-Zu Yang, Dong-Ping Zhan, Zhong-Qun Tian, Shao-Min Zhou

Journal of Electrochemistry

In this paper, the copper interconnection technology in chip manufacturing is introduced in detail, and the essentials of acidic copper sulfate electroplating process and the mechanisms of common-used additives are reviewed. The progresses of novel additives at home and abroad are also summarized. Based on the studied achievement, the possibility of the novel copper interconnect process replacing the acidic copper electroplating is prospected.

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Mxenes As Flow Electrodes For Capacitive Deionization Of Wastewater, Naqsh E. Mansoor Aug 2020

Mxenes As Flow Electrodes For Capacitive Deionization Of Wastewater, Naqsh E. Mansoor

Boise State University Theses and Dissertations

The energy-water nexus poses an integrated research challenge, while opening up an opportunity space for the development of energy efficient technologies for water remediation. Capacitive Deionization (CDI) is an upcoming reclamation technology that uses a small applied voltage applied across electrodes to electrophoretically remove dissolved ionic impurities from wastewater streams. Similar to a supercapacitor, the ions are stored in the electric double layer of the electrodes. Reversing the polarity of applied voltage enables recovery of the removed ionic impurities, allowing for recycling and reuse. Simultaneous materials recovery and water reclamation makes CDI energy efficient and resource conservative, with potential to …

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Nano- And Micro-Structured Temperature-Sensitive Hydrogels For Rapidly Responsive Devices, Qi Lu Jul 2020

Nano- And Micro-Structured Temperature-Sensitive Hydrogels For Rapidly Responsive Devices, Qi Lu

Doctoral Dissertations

This thesis aims to extend the understanding and explore the application of temperature-responsive hydrogel systems by integrating microelectromechanical systems (MEMS). Stimuli-responsive hydrogel systems are immensely investigated and applied in numerous fields, and interfacing with micro- and nano-fabrication techniques will open up more possibilities. In Chapter 2, the first biologically relevant, in vitro cell stretching device based on hydrogel surface instability was developed. This dynamic platform is constructed by embedding micro-heater devices under temperature-responsive surface-attached hydrogels. The fast and regional temperature change actuates the stretching and relaxation of the seeded human artery smooth muscle cell (HASMC) via controllable surface creasing instability. …

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Synthesis, Self-Assembly And High-Pressure Properties Of Nanoparticles And Hybrid Nanocomposites, Lingyao Meng Jul 2020

Synthesis, Self-Assembly And High-Pressure Properties Of Nanoparticles And Hybrid Nanocomposites, Lingyao Meng

Nanoscience and Microsystems ETDs

Nanoparticles have gained significant scientific interests owing to their unique structural dimensions, size- and shape-tunable properties, and numerous fascinating applications, from opto-electronics, sensor devices, to energy, environmental, and medical fields. Furthermore, the synergistic integration of other materials, including organic polymers, with nanoparticles provides new opportunities and strategies to obtain nanocomposites with superior properties and functionalities. While there is already significant research on the synthesis and characterizations of nanoparticles and hybrid nanocomposites, some research questions, such as how to design and control the interfacial morphology in polymer/nanoparticle hybrid nanocomposites, how to synthesize metal- organic framework (MOF) nanoparticles in well-defined and uniform …

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Preparations Of Nano-MnoX/Ti Electrocatalytic Membrane Electrode For Catalytic Oxidation Of Cyclohexane Using Intermittent Electrodeposition, Xue Zhou, Hong Wang, Zhen Yin, Yu-Jun Zhang, Jian-Xin Li Jun 2020

Preparations Of Nano-MnoX/Ti Electrocatalytic Membrane Electrode For Catalytic Oxidation Of Cyclohexane Using Intermittent Electrodeposition, Xue Zhou, Hong Wang, Zhen Yin, Yu-Jun Zhang, Jian-Xin Li

Journal of Electrochemistry

Cyclohexanone and cyclohexanol (KA oil) obtained from highly selective oxidation of cyclohexane (CHA) show important industrial value and application prospects. In this work, the intermittent electrodeposition was developed to prepare nano-MnOx catalyst loading porous tubular titanium membrane electrode (MnOx/Ti), which was employed to constitute an electro-catalytic membrane reactor (ECMR) for the oxidation of cyclohexane to produce cyclohexanol and cyclohexanone. The surface morphology, crystal structure and electrochemical property of the catalysts were characterized by FESEM, XRD and electrochemical workstation, respectively. The results show that the catalyst prepared by the intermittent electrodeposition displayed nano-flower-like γ-MnO2. Compared …

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Synthesis And Raman Study Of Hollow Core-Shell Ni1.2Co0.8P@N-C As An Anode Material For Sodium-Ion Batteries, Jia-Hui Chen, Xiao-Bin Zhong, Chao He, Xiao-Xiao Wang, Qing-Chi Xu, Jian-Feng Li Jun 2020

Synthesis And Raman Study Of Hollow Core-Shell Ni1.2Co0.8P@N-C As An Anode Material For Sodium-Ion Batteries, Jia-Hui Chen, Xiao-Bin Zhong, Chao He, Xiao-Xiao Wang, Qing-Chi Xu, Jian-Feng Li

Journal of Electrochemistry

With the increasing demand for large-scale energy storage, great progress has been made in discovering new advanced energy storage materials. Sodium-ion batteries (SIBs) have attracted much attention in recent years due to their use of abundant sodium resources and their comparable electrochemical capacity to lithium-ion batteries (LIBs). In this paper, we developed novel hollow core-shell Ni-Co bimetallic phosphide nanocubes with N-doped carbon coatings (Ni1.2Co0.8P@N-C) as the anode material for SIBs. The material was synthesized through a low-temperature phosphorization method using resorcinol formaldehyde (RF) resin coating with a Ni-Co Prussian blue analogue (PBA) as a template and …

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Spectroscopic Investigations Of Excited Charge Carriers In Ii-Vi Nanoparticles, William Matthew Sanderson May 2020

Spectroscopic Investigations Of Excited Charge Carriers In Ii-Vi Nanoparticles, William Matthew Sanderson

Arts & Sciences Electronic Theses and Dissertations

The large absorption cross sections and the tunability of the energetic spacings between the states in the conduction (CB) and valence band (VB) within a semiconductor nanoparticle (NP) make them promising media for capturing electromagnetic radiation and converting it into charge carriers, or electricity. In photovoltaic devices that incorporate semiconductor NPs, it would be ideal if every photon could be absorbed by a NP and the carriers could be collected with perfect efficiency and without loss of energy. The relaxation pathways of the carriers within the NPs down to the band edge and their fate at the band edge contribute …

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Fabrication Of Nanoscale Columnar Diodes By Glancing Angle Deposition, Jacob D. Weightman May 2020

Fabrication Of Nanoscale Columnar Diodes By Glancing Angle Deposition, Jacob D. Weightman

Macalester Journal of Physics and Astronomy

Glancing angle deposition (GLAD) is a process in which thin films are deposited onto a substrate with obliquely incident vapor together with precisely controlled azimuthal substrate rotation. Ballistic shadowing effects due to the oblique incidence produce nanoscale structures, and a variety of feature shapes, including tilted columns, helices, and vertical columns can be achieved by varying the azimuthal rotation during the deposition process. Due to this control of morphology and the compatibility of the process with a wide variety of materials, GLAD films have found applications in a variety of fields including sensing, photonics, photovoltaics, and catalysis, where they are …

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Resistive Switching Characteristics Of Nanostructured And Solution-Processed Complex Oxide Assemblies, Zimu Zhou May 2020

Resistive Switching Characteristics Of Nanostructured And Solution-Processed Complex Oxide Assemblies, Zimu Zhou

Doctoral Dissertations

Miniaturization of conventional nonvolatile (NVM) memory devices is rapidly approaching the physical limitations of the constituent materials. An emerging random access memory (RAM), nanoscale resistive RAM (RRAM), has the potential to replace conventional nonvolatile memory and could foster novel type of computing due to its fast switching speed, high scalability, and low power consumption. RRAM, or memristors, represent a class of two terminal devices comprising an insulating layer, such as a metal oxide, sandwiched between two terminal electrodes that exhibits two or more distinct resistance states that depend on the history of the applied bias. While the sudden resistance reduction …

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Size-Dependent Inhibitory Effects Of Antibiotic Nanocarriers On Filamentation Of E. Coli, Preeyaporn Songkiatisak, Feng Ding, Pavan Kumar Cherukuri, Xiao-Hong Nancy Xu May 2020

Size-Dependent Inhibitory Effects Of Antibiotic Nanocarriers On Filamentation Of E. Coli, Preeyaporn Songkiatisak, Feng Ding, Pavan Kumar Cherukuri, Xiao-Hong Nancy Xu

Chemistry & Biochemistry Faculty Publications

Multidrug membrane transporters exist in both prokaryotic and eukaryotic cells and cause multidrug resistance (MDR), which results in an urgent need for new and more effective therapeutic agents. In this study, we used three different sized antibiotic nanocarriers to study their mode of action and their size-dependent inhibitory effects against Escherichia coli (E. coli). Antibiotic nanocarriers (AgMUNH–Oflx NPs) with 8.6 × 102, 9.4 × 103 and 6.5 × 105 Oflx molecules per nanoparticle (NP) were prepared by functionalizing Ag NPs (2.4 ± 0.7, 13.0 ± 3.1 and 92.6 ± 4.4 nm) with a monolayer …

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Nio@Rgo Supported Palladium And Silver Nanoparticles As Electrocatalysts For Oxygen Reduction Reaction, Shuo Yao, Tai-Zhong Huang, Rizwan Haider, Heng-Yi Fang, Jie-Mei Yu, Zhan-Kun Jiang, Dong Liang, Yue Sun, Xian-Xia Yuan Apr 2020

Nio@Rgo Supported Palladium And Silver Nanoparticles As Electrocatalysts For Oxygen Reduction Reaction, Shuo Yao, Tai-Zhong Huang, Rizwan Haider, Heng-Yi Fang, Jie-Mei Yu, Zhan-Kun Jiang, Dong Liang, Yue Sun, Xian-Xia Yuan

Journal of Electrochemistry

For pervasive applications of fuel cells, highly efficient and economical materials are required to replace Pt-based catalysts for oxygen reduction reaction (ORR). In this study, the NiO@rGO, Pd-NiO@rGO and Ag-NiO@rGO nanoparticles were synthesized, and their catalytic performances toward ORR were investigated. The results revealed that all the three materials were capable of catalyzing ORR, but both the Pd-NiO@rGO and Ag-NiO@rGO showed the better performances compared with the NiO@rGO in terms of the reaction pathway being 4-electron process, the increases of the onset potential and the intermediate yielding rate, as well as the extended stability. Moreover, the effect of Pd modification …

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Construction And Electrochemical Performance Of Garnet-Type Solid Electrolyte/Al-Li Alloy Interface, Jia-Lin Ma, Hong-Chun Wang, Zheng-Liang Gong, Yong Yang Apr 2020

Construction And Electrochemical Performance Of Garnet-Type Solid Electrolyte/Al-Li Alloy Interface, Jia-Lin Ma, Hong-Chun Wang, Zheng-Liang Gong, Yong Yang

Journal of Electrochemistry

Garnet-type solid electrolyte is a newly developed Li ion conductor and promising in the application of all-solid-state batteries. However, Garnet is incompatible with Li anode, which restricts the application of Garnet-type solid batteries. In order to improve the contact between Garnet-type solid electrolyte and Li electrode, a composite anode which contains Al-Li alloy (Al4Li9) was prepared as an electrode. Al-Li alloy has many advantages such as easy preparation, low cost, simple post-treatment and high capacity. Garnet-type Li6.5La3Zr1.75W0.25O12 (LLZWO) was synthesized via solid-state reaction. Garnet solid electrolyte has …

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Quantifying Wicking In Functionlized Surfaces, Maureen Winter, Ryan Regan, Alfred Tsubaki, Craig Zuhlke, Dennis Alexander, George Gogos Apr 2020

Quantifying Wicking In Functionlized Surfaces, Maureen Winter, Ryan Regan, Alfred Tsubaki, Craig Zuhlke, Dennis Alexander, George Gogos

UCARE Research Products

Wicking remains the enigmatic key factor in many research areas. From boiling in power plants, to anti-icing on plane wings, to medical instruments, to heat pipes, efficiency and safety depend on how quickly a surface becomes wet. Yet wicking remains difficult to quantify and define as a property of the surface. This experiment strives to measure the wicking property by examining the rate that a liquid can be pulled out of a container. A superhydrophilic surface is placed in contact with the liquid at the bottom of a tube so that the volume flow rate across the surface can be …

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Enhanced Carrier Transport By Transition Metal Doping In Ws2 Field Effect Transistors, Maomao Liu, Sichen Wei, Simran Shahi, Hemendra Nath Jaiswal, Paolo Paletti, Sara Fathipour, Maja Remskar, Jun Jiao, Wansik Hwang, Fei Yao, Huamin Li Apr 2020

Enhanced Carrier Transport By Transition Metal Doping In Ws2 Field Effect Transistors, Maomao Liu, Sichen Wei, Simran Shahi, Hemendra Nath Jaiswal, Paolo Paletti, Sara Fathipour, Maja Remskar, Jun Jiao, Wansik Hwang, Fei Yao, Huamin Li

Physics Faculty Publications and Presentations

High contact resistance is one of the primary concerns for electronic device applications of two-dimensional (2D) layered semiconductors. Here, we explore the enhanced carrier transport through metal–semiconductor interfaces in WS2 field effect transistors (FETs) by introducing a typical transition metal, Cu, with two different doping strategies: (i) a “generalized” Cu doping by using randomly distributed Cu atoms along the channel and (ii) a “localized” Cu doping by adapting an ultrathin Cu layer at the metal–semiconductor interface. Compared to the pristine WS2 FETs, both the generalized Cu atomic dopant and localized Cu contact decoration can provide a Schottky-to-Ohmic contact …

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Engineered Nanoparticles For Site-Specific Bioorthogonal Catalysis: Imaging And Therapy, Riddha Das Mar 2020

Engineered Nanoparticles For Site-Specific Bioorthogonal Catalysis: Imaging And Therapy, Riddha Das

Doctoral Dissertations

Bioorthogonal catalysis offers a strategy for chemical transformations complementary to bioprocesses and has proven to be a powerful tool in biochemistry and medical sciences. Transition metal catalysts (TMCs) have emerged as a powerful tool to execute selective chemical transformations, however, lack of biocompatibility and stability limits their use in biological applications. Incorporation of TMCs into nanoparticle monolayers provides a versatile strategy for the generation of bioorthogonal nanocatalysts known as “nanozymes”. We have fabricated a family of nanozymes using gold nanoparticles (AuNPs) as scaffolds featuring diverse chemical functional groups for controlled localization of nanozymes in biological environments, providing unique strategies for …

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Electrochemical Preparations And Applications Of Nano-Catalysts With High-Index Facets, Chi Xiao, Na Tian, Zhi-You Zhou, Shi-Gang Sun Feb 2020

Electrochemical Preparations And Applications Of Nano-Catalysts With High-Index Facets, Chi Xiao, Na Tian, Zhi-You Zhou, Shi-Gang Sun

Journal of Electrochemistry

The performance of catalysts highly depends on their surface structure and composition. Nanocrystals bounded by high-index facets usually exhibit high catalytic activity due to their high-density low-coordinated step atoms with high reactivity. In this paper, we have reviewed the preparations of noble metals (e.g., Pt, Pd and Rh) nanocatalysts with high-index facets by electrochemical square-wave potential method developed in our group. The square-wave potential method includes a nucleation procedure to generate nuclei, followed by a square-wave potential procedure for a certain period of time for the growth of nuclei into nanocrystals. The formation mechanism of high-index facets is also discussed. …

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Mechanical And Structural Behavior Of As-Built And Post Treated Ti6al4v Lattice Structures Fabricated By Selective Laser Melting (Slm), Hala Ahmed Salem Jan 2020

Mechanical And Structural Behavior Of As-Built And Post Treated Ti6al4v Lattice Structures Fabricated By Selective Laser Melting (Slm), Hala Ahmed Salem

Theses and Dissertations

Lattice structure is a type of cellular structures that is composed of repeatable unit cells, each of which is formed of interconnect network of struts. Lattices with different structures are gaining attention for their good mechanical properties for light weight applications. Selective laser melting (SLM), is one of the AM powder-bed fusion fabrication techniques. SLM is widely known for its capability for fabricating complex metallic structures such as lattice structures with high resolution. SLM process influence the microstructure and mechanical properties of fabricated parts. The used processing parameters influence the level of internal porosity within the fabricated parts which directly …

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Multiscale Modeling Of Carbon Fibers/Graphene Nanoplatelets/Epoxy Hybrid Composites For Aerospace Applications, Hashim Al Mahmud Jan 2020

Multiscale Modeling Of Carbon Fibers/Graphene Nanoplatelets/Epoxy Hybrid Composites For Aerospace Applications, Hashim Al Mahmud

Dissertations, Master's Theses and Master's Reports

Significant research effort has been dedicated for decades to improve the mechanical properties of aerospace polymer-based composite materials. Lightweight epoxy-based composite materials have increasingly replaced the comparatively heavy and expensive metal alloys used in aeronautical and aerospace structural components. In particular, carbon fibers (CF)/graphene nanoplatelets (GNP)/epoxy hybrid composites can be used for this purpose owing to their high specific stiffness and strength. Therefore, this work has been completed to design, predict, and optimize the effective mechanical properties of CF/GNP/epoxy composite materials at different length scales using a multiscale modeling approach. The work-flow of modeling involves a first step of using …

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Surface And Structure Engineering For Next Generation Lithium Metal Batteries, Ke Chen Jan 2020

Surface And Structure Engineering For Next Generation Lithium Metal Batteries, Ke Chen

Electronic Theses and Dissertations

Lithium (Li) metal has been considered as one of the most promising anode materials to replace conventional graphite for Li-ion battery due to its high theoretical capacity (3860 mAh g-1) and low electrochemical potential (-3.04 V vs standard hydrogen electrode). However, it still faces some problems such as unstable solid electrolyte interphase (SEI), uncontrolled Li dendrites growth, and infinite volume change during battery charging/discharging. To develop a stable and low-cost Li metal anode for next-generation Li metal battery, in this dissertation, we have made efforts to understand and solve these problems in two aspects, by introducing an artificial SEI and …

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