Nanoscience and Nanotechnology Commons^™

Single Particle-Inductively Coupled Plasma-Mass Spectrometry Technology Development For Metallic Nanoparticle Characterization In Complex Matrices, Yongbo Dan

Doctoral Dissertations

"As the rapid growing of nanotechnology, the release of engineered nanoparticles (ENPs) into the environment is inevitable. After entering the real environment, ENPs tend to react with different components of the ecosystem (e.g. water, soil, air, plants) and make their characterization difficult. Analyzing ENPs in these complex matrices still remains as a grand challenge. ENPs characterization is normally the first step of risk assessment. Current analytical techniques have shown some limitations in revealing the unique characteristics of ENPs in complex matrices and reliable analytical techniques are in urgent need. Single particle inductively coupled plasma mass spectrometry (SP-ICP-MS) is an emerging …

Synthesis Of Porous Carbon Nanosheets And Its Application In Sodium-Ion Battery, Jing-Fei Zhang, Jing Lu, Xiao-Yu Yang, Yun-Di Huang, Lin Xu, Dong-Mei Sun, Ya-Wen Tang

Journal of Electrochemistry

Owning to sodium’s high abundance, relatively low cost, similar chemical properties to Li and very suitable redox potential of E₀(Na⁺/Na) = -2.71 V versus SHE which is only 0.3 V above that of lithium, rechargeable sodium ion battery hold much promise as potential alternatives to current lithium ion batteries for energy storage applications. Carbon material is regarded as the most promising anode candidate for sodium ion battery. Particularly, carbon nanosheet with porous structure and high conductivity is expected to have improved sodium ion storage properties. In this paper, we present a two-step pyrolysis-based method for facile …

Intercalation Of Clo4- Into Hopg Investigated By Ec-Stm, Xiao-Yan Hu, Alice Aliwowe, Jia-Wei Yan, Bing-Wei Mao

Journal of Electrochemistry

The electrochemical intercalation and surface morphology of highly oriented pyrolytic graphite (HOPG) electrode in 2 mol⋅L^-1 HClO₄ were studied by in situ scanning tunneling microscopy (STM) and cyclic voltammetry (CV). Based on the step-height changes observed before and after the intercalation, the effects of different step sites on intercalation are compared. The feasibility, reversibility and speed of intercalation are discussed. The intercalation ofClO₄^- into HOPG can be divided into three types depending on the number of graphite layers at the step site: When the layers of graphite are more than three, the intercalation becomes feasible; when …

Electrochemical Properties Of Graphene/Porous Nano-Silicon Anode, Chun-Li Li, Guang Yang, Ping Zhang, Zhi-Yu Jiang

Journal of Electrochemistry

Porous nano-silicon (Si) was prepared by acid etching Al-Si alloy powder method, and used as an active material for fabricating a grapene/porous nano-Si electrode. The results of SEM and TEM measurements indicated that porous nano-Si powder was uniformly mixed with graphene by emulsification dispersion-ultrasonication method. As an anode for lithium ion battery, the graphene/porous nano-Si electrode presented relatively high performance in 1 mol•L^-1LiPF6/EC:DMC = 1:1(by volume) + 1.5% (by mass) VC solution. At the charge and discharge current densities of 0.5A•g^-1, the first discharge capacity was 1768.6mAh•g^-1with coulombic efficiency of 68.3%. The discharge capacity …

Turning An Organic Semiconductor Into A Low-Resistance Material By Ion Implantation, Beatrice Fraboni, Alessandra Scidà, Piero Cosseddu, Yongqiang Wang, Michael Nastasi, Silvia Milita, Annalisa Bonfiglio

Nebraska Center for Energy Sciences Research: Publications

We report on the effects of low energy ion implantation on thin films of pentacene, carried out to investigate the efficacy of this process in the fabrication of organic electronic devices. Two different ions, Ne and N, have been implanted and compared, to assess the effects of different reactivity within the hydrocarbon matrix. Strong modification of the electrical conductivity, stable in time, is observed following ion implantation. This effect is significantly larger for N implants (up to six orders of magnitude), which are shown to introduce stable charged species within the hydrocarbon matrix, not only damage as is the case …

Three Dimensional Nanowire Array Piezo-Phototronic And Piezo-Photo-Magnetotronic Sensors, Satish C. Rai

LSU New Orleans Theses and Dissertations

Piezotronic and piezo-phototronic is a burgeoning field of study which emerges from the coupling of intrinsic materials properties exhibited by non-centrosymmetric semiconductors. In the past decade research efforts were mainly focused on the wurtzite family of 1D nanostructures, with major emphasis on ZnO nanowire nanogenerators, MS piezotronic transistors, LEDs and photodetectors mainly integrated on single nanowires. In view of previously known advantages of charge carrier separation in radial heterojunctions, particularly in type-II core/shell nanowires, it can be anticipated that the performance of photosensing devices can be largely enhanced by piezo-phototronic effect. Moreover, the performance metrics can be further improved in …

When 1 + 1 > 2: Nanostructured Composites For Hard Tissue Engineering Applications, Vuk Uskoković

Pharmacy Faculty Articles and Research

Multicomponent, synergistic and multifunctional nanostructures have taken over the spotlight in the realm of biomedical nanotechnologies. The most prospective materials for bone regeneration today are almost exclusively composites comprising two or more components that compensate for the shortcomings of each one of them alone. This is quite natural in view of the fact that all hard tissues in the human body, except perhaps the tooth enamel, are composite nanostructures. This review article highlights some of the most prospective breakthroughs made in this research direction, with the hard tissues in main focus being those comprising bone, tooth cementum, dentin and enamel. …

Epitaxial Growth Of Si-Ge-Sn Alloys For Optoelectronic Device Application, Aboozar Mosleh

Graduate Theses and Dissertations

Microelectronics industry has experienced a tremendous change over the last few decades and has shown that Moore’s law has been followed by doubling the number of transistors on the chip every 18 months. However, continuous scaling down of the transistors size is reaching the physical limits and data transfer through metal interconnects will not be able to catch up with the increasing data processing speed in the future. Therefore, optical data transfer between chips and on-chip has been widely investigated. Silicon based optoelectronics has received phenomenal attention since Si has been the core material on which microelectronic industry has been …

Imaging Thermal Conductivity With Nanoscale Resolution Using A Scanning Spin Probe, Abdelghani Laraoui, Halley Aycock-Rizzo, Yang Gao, Xi Lu, Elisa Riedo, Carlos A. Meriles

Department of Mechanical and Materials Engineering: Faculty Publications

The ability to probe nanoscale heat flow in a material is often limited by lack of spatial resolution. Here, we use a diamond-nanocrystal-hosted nitrogen-vacancy centre attached to the apex of a silicon thermal tip as a local temperature sensor. We apply an electrical current to heat up the tip and rely on the nitrogen vacancy to monitor the thermal changes the tip experiences as it is brought into contact with surfaces of varying thermal conductivity. By combining atomic force and confocal microscopy, we image phantom microstructures with nanoscale resolution, and attain excellent agreement between the thermal conductivity and topographic maps. …

Optical Communication Using Hybrid Micro Electro Mechanical Structures (Mems) And Commercial Corner Cube Retroreflector (Ccr), Sunny Kedia

USF Tampa Graduate Theses and Dissertations

This dissertation presents a free-space, long-range, passive optical communication system that uses electrostatically modulated microelectromechanical systems (MEMS) structures coupled with a glass total internal reflection (TIR)-type corner cube retroreflector (CCR) as a non-emitting data transmitter. A CCR consists of three mirrors orthogonal to each other, so that the incident beam is reflected back to the incident beam, source. The operational concept is to have a MEMS modulator fusion with TIR CCR, such that the modulators are working periodically to disrupt the evanescent waves at the air interface of one of the three back glass faces of a TIR CCR. The …

In Vacuo Fabrication And Electronic Structure Characterization Of Atomic Layer Deposition Thin Films, Michael Schaefer

USF Tampa Graduate Theses and Dissertations

Improvement of novel electronic devices is possible by tailor-designing the electronic structure at device interfaces. Common problems observed at interfaces are related to unwanted band alignment caused by the chemical diversity of interface partners, influencing device performance negatively. One way to address this problem is by introducing ultra-thin interfacial dipole layers, steering the band alignment in a desired direction. The requirements are strict in terms of thickness, conformity and low density of defects, making sophisticated deposition techniques necessary. Atomic layer deposition (ALD) with its Ångstrom-precise thickness control can fulfill those requirements.

The work presented here encompasses the implementation of an …

Direct Solutions To Perceptual Organization Problems, Ravi Kumar Panchumarthy

USF Tampa Graduate Theses and Dissertations

Quadratic optimization problems arise in various real world application domains including engineering design, microeconomics, genetic algorithms, integrated circuit chip design, probabilistic graphical models and computer vision. In particular, there are many problems in computer vision that require binary quadratic optimization such as motion segmentation, correspondences, figure-ground segmentation, clustering, grouping, subgraph matching, and digital matting. The objective of an optimization algorithm can be related to the state of a physical system, where the goal is to bring the initial arbitrary state of the system to a state with minimum possible energy. By recognizing that the Hamiltonian of nanomagnets can be expressed …

P-31 Characterization And Ph Dependence Stability Of Non-Organically Supported Silver Nanoparticles Produced Via Silver Oxide Reduction, Getahun Merga, Noah Chun

Celebration of Research and Creative Scholarship

The non-organically supported silver nanoparticles produced via the reduction of silver oxide by hydrogen and acetvlacetone (acac) have unusual stability in aqueous solution. We have previously reported that the negative potential, the hydrophilic surface that is created by the adsorbed hydroxide ions, which resembles an oxide interface, and the low ionic strength of the solution due to the small salt concentrations in this synthetic approach all contribute to the unusual stability of the colloidal suspension.[1] However, their stability with pH variation has not been well documented. In order to use these silver nanoparticles for biological relevance understanding of their suspension …

Molecular Helices As Electron Acceptors In High-Performance Bulk Heterojunction Solar Cells, Yu Zhong, M. Tuan Trinh, Rongsheng Chen, Geoffrey E. Purdum, Petr P. Khlyabich, Melda Sezen, Seokjoon Oh, Haiming Zhu, Brandon Fowler, Boyuan Zhang, Wei Wang, Chang-Yong Nam, Matthew Y. Sfeir, Charles T. Black, Michael L. Steigerwald, Yueh-Lin Loo, Fay Ng, X.-Y. Zhu, Colin Nuckolls

Publications and Research

Despite numerous organic semiconducting materials synthesized for organic photovoltaics in the past decade, fullerenes are widely used as electron acceptors in highly efficient bulk-heterojunction solar cells. None of the non-fullerene bulk heterojunction solar cells have achieved efficiencies as high as fullerene-based solar cells. Design principles for fullerene-free acceptors remain unclear in the field. Here we report examples of helical molecular semiconductors as electron acceptors that are on par with fullerene derivatives in efficient solar cells. We achieved an 8.3% power conversion efficiency in a solar cell, which is a record high for non-fullerene bulk heterojunctions. Femtosecond transient absorption spectroscopy revealed …

Nanomechanical And Nanotribological Characterization Of Sub-Micron Polymeric Spheres, Himanshu Kumar Verma

USF Tampa Graduate Theses and Dissertations

Friction between nanoscale objects has been a subject of great interest and intense research effort for the last two decades. However, the vast majority of the work done in this area has focused upon the sliding friction between two rigid, atomically smooth surfaces. Thus the parameter most explored has been the corrugation in the atomic potentials and how this affects the force required to slide one object across another. In truth, many nanoscale objects whose translation force is of practical interest are more spherical in nature. We hypothesize that the factors that determine the translation force will be related, not …

A Comparative Study Of Polyurethane Nanofibers With Different Patterns And Its Analogous Nanofibers Containing Mwcnts, Javier Macossay-Torres, Faheem A. Sheikh, Hassan Ahmad, Hern Kim, Gary L. Bowlin

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

Tissue engineering is a multidisciplinary field that has evolved in various dimensions in recent years. One of the main aspects in this field is the proper adjustment and final compatibility of implants at the target site of surgery. For this purpose, it is desired to have the materials fabricated at the nanometer scale, since these dimensions will ultimately accelerate the fixation of implants at the cellular level. In this study, electrospun polyurethane nanofibers and their analogous nanofibers containing MWCNTs are introduced for tissue engineering applications. Since MWCNTs agglomerate to form bundles, a high intensity sonication procedure was used to disperse …

Preparation And Characterization Of Carbon Supported Pd-Sb Composite Nanocatalysts For Formic Acid Electrooxidation, Long-Long Wang, Xiao-Lu Cao, Ya-Jun Wang, Jin-Hao Ping, Qiao-Xia Li

Journal of Electrochemistry

Palladium is considered as an efficient anode catalyst with high catalytic activity for electrooxidation of formic acid. To further improve the catalytic activity and stability, alloying or surface modification with Sb is an effective way. In this work, the well dispersed carbon supported Pd-Sb composite nanocatalysts (Pd-Sb/C) were synthesized by traditional impregnation reduction method with trisodium citrate as the complexing agent, sodium borohydride as the reducing agent. The morphologies of Pd-Sb/C and the effects of molar ratio of Pd to Sb on the electrocatalytic properties of Pd-Sb/C for HCOOH electrooxidation were studied. The XRD and XPS analyses on the as-prepared …

Effect Of Adsorption Potential On Co Oxidation At Au@Pt Nanoparticles Electrodes, A Surface Enhanced Raman Spectroscopic Study, Pu Zhang, Yi Wei, Yong-Li Zheng, Yan-Xia Chen, Zhong-Qun Tian

Journal of Electrochemistry

The adsorption/oxidation of CO on the 55 nm [email protected] nm Pt nanoparticles electrode in both potentiodynamic and potentiostatic modes were investigated by surface enhanced Raman spectroscopy in a thin layer electrochemical flow cell under controlled mass transport, with the aim of clarifying the origin CO oxidation at lower electrode potentials (in current pre-wave region of corresponding cyclic voltammograms). Our results demonstrated that the CO oxidation kinetics differed significantly from the three kinds of different CO adsorption history, with almost no CO oxidation current in the pre-peak potential region after 0.35 V_RHE CO adsorption with or without subsequent holding the …

Broadband Sum-Frequency Generation Spectroscopic Invstigations Of Thiocyanate On Polycrystalline Au Electrode In Alkaline Solutions, Mei Xu, Jing-Jing Wang, Zhi-Chao Huangfu, Ng Ying Wa, Yu-Han He, Zhao-Hui Wang

Journal of Electrochemistry

Broadband sum frequency generation (BB-SFG) spectroscopy has been used to investigating the potential-dependent adsorption behaviors of thiocyanate ions on polycrystalline Au electrode in alkaline solutions. During the positive scan, a change in the Stark slope (dω_C-N/dE) for C—N stretching mode can be observed in the range of -1.1 V ~ 0.2 V (vs. SCE), which implies that the orientation of adsorbed thiocyanate ions at Au electrode surface changes from N-bound (dω_C-N/dE=45 cm^-1·V^-1) form to S-bound (dω_C-N/dE = 16.2 cm^-1·V^{-1 …}

Effect Of Carbon Nanotubes On Anodic Properties Of Ti/Ru-Ir-Sn Oxides, Feng Lian, Yong-Lei Xin, Bo-Jiang Ma, Li-Kun Xu

Journal of Electrochemistry

The Ru-Ir-Sn metal oxide anodes coated on titanium (Ti/Ru-Ir-Sn) were prepared by thermal decomposition. The effects of amounts of carbon naotubes (CNTs) on anodic properties were studied by TGA, SEM, EDS, cyclic voltammetry, EIS, polarization measurements and accelerated life test. The thermogravimetric analysis and EDS spectrum data showed that the high temperature oxidation decomposition of CNTs did not take place under the condition of the sintering temperature of 470 ℃, and the CNTS still existed in the anode coating in an element form. Compared with the contrast samples, the surface crack of the coating increased, but remained typical morphology. Adding …