3^rd International Conference and Expo on Graphene, Advanced 2D Materials & Semiconductors March 28, 29 2019 Orlando, Florida, USA

Biography:

Junji Tominaga is a Prime Senior researcher in the Nanoelectronics Research Institute at the National Institute of Advanced Industrial Science and Technology (AIST), Japan. He received his PhD degree from Cranfield University, UK, in 1991. After studying optical phase-change memory at TDK Corporation, he joined AIST in 1997. He was the director of the Center for Applied Near-Field Optics Research until 2009. His research focuses on phase-change materials and application. He is the inventor of the super-resolution near-field structure (super-RENS) and the interfacial phase-change memory (iPCM) device. He was awarded the S.R. Ovshinsky Lectureship Award in 2014. He is a Fellow of The Optical Society and a member of IOP.    

Abstract:

Multiferroics is a keyword for future electronics. However, it is still difficult to induce large electrical and magnetic properties at room temperature. It relies on that electric dipole moments are usually related to p-electrons while the magnetic moments are to d-electrons. If a large magnetic moment is induced from p-electrons, giant multiferroics would be possible. A combination of a topological insulator and a ferroelectric insulator may open a new era to realize such the multifunctionality. Topological insulators, such as Bi₂Te₃ and Sb₂Te₃, usually satisfy both spatial inversion and time reversal symmetry. The topological surface bands are mainly made of the band inversion of 6p- or 5p-electrons of Te, Sb, and Bi. On the other hand, GeTe is known as a ferroelectric material, which has a large spin-orbit coupling (SOC) compared with other oxide ferroelectric materials. Due to the large SOC, it shows a large Rashba-like spin split band. It is noted here that the existence of an electric dipole moment breaks the spatial inversion symmetry. If thin films of Sb₂Te₃ and GeTe are piled up alternatively, what happens on the band structure as the bulk film? Actually, both layers can share a lattice plane using (0001) and (111) through a van der Waals force. As the bulk film, the spatial inversion symmetry is broken. Therefore, plural Dirac cones appear apart from the Γ-point in the k-space, resulting in a Weyl semimetal. Weyl semimetals are magnetic sensitive because spin bands are lifted from the band degeneration. In the presentation, we show several experimental results of the Weyl semimetal from superlattices consisted of GeTe and Sb₂Te₃ sublayers at room temperature.

Biography:

Berangere Toury is Assistant Professor at the University of Lyon. She got her permanent position in 2003 after 2 consecutive post-doctorates at the University of Hull (GB) and at the University Paris VI and a Ph.D. obtained in 2000, all in the chemistry of inorganic materials. Her research activity is focused on the design, the synthesis and the characterization of innovative inorganic or hybrid O/I materials (BN, SiO₂, CeO₂…) using polymer routes. She has published more than 50 papers in reputed journals and she is co-inventor of 7 patterns.

Abstract:

Prompted by the rising star of graphene, 2D nanomaterials are now a hot issue in the scientific world. Among them, the h-BN nanosheet (BNNS), consisting of thin atomic layers made of B and N atoms covalently bounded, is particularly relevant. Actually, BNNS has shown to be an excellent gate dielectric support for graphene and other two-dimensional materials owing to its atomically smooth surface, high thermal conductivity and stability combined with high mechanical strength. Compared with conventional SiO₂ substrate, lattice matching and absence of dangling bonds make BNNS and graphene excellent pairing materials and give the incentive to develop various Van der Waals heterostructures. However, it has to be pointed out that such applications cannot be put into use without high purity large BNNSs. In order to achieve high quality and large BNNSs, we propose a novel synthesis way by the Polymer Derived Ceramics (PDCs) route involving polyborazylene as a precursor, combined with the Spark Plasma Sintering (SPS). This promising approach allows synthesizing pure and well-crystallized h-BN flakes, which can be easily exfoliated into BNNSs. Here we present recent investigations on how to optimize the process, considering the influences of both sintering temperature (1200°C to 1950°C) and crystallization promoter ratio (0 to 10wt%) on h-BN. Structural studies were led by TEM and Raman spectroscopy. Both methods evidence a very high crystalline quality attested by the LWHM value, 7cm^-1, as the best reported in the literature. More original characterizations were carried out by cathodoluminescence to prove the high BNNSs purity from both chemical and structural point of view.

Biography:

Qing Tu is an expert on solid mechanics, 2D materials and scanning probe microscopy. His PhD research focuses on the interfacial properties of 2D materials and heterostructures by scanning probe microscopy, which won the outstanding dissertation award from Pratt School of Engineering at Duke University. He is currently a postdoc at Northwestern University Atomic and Nanoscale Characterization and Experimental (NUANCE) center. He is investigating the structure-property relationship of 2D hybrid organic inorganic perovskites and developing novel scanning probe microscopy techniques for nano- and bio-materials characterizations. 

Abstract:

2D materials, e.g., graphene, and heterostructures have extraordinary properties compared to their 3D counterparts and have great potential for a broad range of applications, including flexible electronic devices, nanocomposites, and transistors. The mechanical properties of 2D materials and heterostructures are both fundamentally and practically important to achieve both high performance and mechanically stable (flexible) devices. The in-plane mechanical properties of 2D materials are primarily dominated by the in-plane bonds in the materials while the out-of-plane mechanical properties are significantly affected by the interfaces between 2D materials and other materials (e.g., substrates). We first develop a first-principles calibrated contact resonance atomic force microscopy (CR-AFM), which is sensitive to mechanical property change arising from one atomic layer difference and is very powerful to investigate the interfacial defects in 2D materials and heterostructures. The measured nanomechanical property can be quantitatively correlated to the local atomic structure through a combined ab initio and continuum mechanics simulations. Furthermore, we discover that the out-of-plane mechanical properties of graphene can be engineered through self-assembled monolayers (SAMs) in the graphene-substrate interfaces. The surface energy of SAMs can be used to modulate the number of water molecules at the graphene-SAM interface, which affects the graphene-SAM interaction strength and the pecking order of SAMs. We further discover the out-of-plane mechanical properties of 2D hybrid organic-inorganic perovskites (HOIPs) depend on the structural parameters of the materials. Finally, the in-plane mechanical properties of 2D HOIPs are a function of the thickness due to interfacial sliding.

Biography:

Christiana Agbo is a research-oriented and hardworking Textiles Engineer with expertise in pigments, dispersants, and the dispersion process. She has a great passion for impacting through teaching and research works. Her ability to identify and solve problems based on research and a good sense of observation creates new pathways for improving faulted processes in the field of pigment dispersion mechanisms and its application for obtaining desired results for the desired end use. She has over the years built a great deal of experience in research and teaching in the educational field. Having attended key educational conferences such as the International Symposium of Functional Textiles as well as co-authored research articles published in key journals, she has gathered great resources for the development of the textile industry. Her main research focuses on dispersant synthesis, pigment dispersion, ink formation, advance fabric finishing, application of inks on various fabric types and digital printing.

Abstract:

In the quest of ensuring successful pigment dispersion, additives are used to aid dispersion and stabilization of pigment particles through attraction forces of various chemical nature including van der Waals and “liquid bridge” forces as well as anchor groups with high affinity for pigment surface. On the other hand, dispersion efficiency is significantly dependent on the effectiveness of various dispersion equipment and their energy transfer, dispersion force, and effectiveness. The common denominator for all this equipment is that; dispersion is achieved by shearing forces produced by the application of high positive and negative attrition. This presentation reviews and explores the nature and the significance of the various methods and forces in pigment dispersion and the various stabilization mechanisms adopted in producing stably fine pigment particles, dispersion application as well as future prospects. In addition, it explores how these mechanisms might apply to liquid-phase exfoliation and dispersion of graphene and other nanomaterial.

Biography:

Morgan Advanced Materials (LSE: MGAM) is a UK-headquartered global manufacturer of specialized engineered products made from carbon, advanced ceramics and composites. It was the first European strategic partner for the graphene activities at the University of Manchester National Graphene Institute (NGI), Morgan being recognized by Manchester for having the product engineering and design expertise required to commercialize the materials developed at the NGI. After being educated as a chemical engineer, Richard Clark has been with Morgan for over 30 years, developing and commercializing materials across the spectrum of Morgan’s portfolio, most recently focusing on materials related to energy. Richard was part of Morgan’s team engaged with the University of Cambridge developing electrolytically produced carbon nanomaterials and has continued his involvement in this field in collaboration with Morgan’s team at the Manchester NGI.

Abstract:

Since the groundbreaking article in Science in October 2004 describing the occurrence, isolation and potential significance of graphene, there has been a huge interest in developing industrially scalable methods of manufacture from bottom-up and top-down routes. One such top-down route developed for the mass manufacture of graphene involves electrochemical exfoliation. This can be conducted in anodic (oxidative) and cathodic (reductive) regimens, with the latter previously considered more suitable for production of higher quality (containing fewer defects) graphene, but hindered by lower efficiency and yield. Generating a high- quality graphene product using an anodic process would therefore be of huge value in potential commercialization. Previous work has shown that graphene prepared by electrochemical exfoliation can be simultaneously functionalized with groups tailored to improve solubility in aqueous systems and with metal nanostructures, specifically various morphologies of gold and cobalt, which show high catalytic activity and stability when used as electrocatalysts for hydrogen evolution reactions. This presentation shows how, using selected transition metal ions such as cobalt (Co2+) and iron (Fe3+), high-quality (low oxygen, more conductive and with few layers) graphene can be produced using an anodic electrochemical exfoliation route. Additionally, it shows how other transition metal ions such as ruthenium (Ru3+) and manganese (Mn2+) can be used as metal oxide decorators. Certain hybrid structures can be uniformly grown on the graphene sheets in a single process and the product is an efficient electrocatalyst for water splitting and a high-performance electrode for supercapacitors (specific capacitance demonstrated over 520 Fg-1). This method also provides an elegant means of utilizing the pseudocapacitance of ruthenium dioxide (RuO₂).

Biography:

Larry G. Christner received his Ph.D. from Pennsylvania State University in 1972 followed by 5 years at United Technologies Corporation working on carbon deposition in steam reforming and materials development for fuel cells. He spent the next 23 years at Fuel Cell Energy starting as manager of materials science and was later promoted as Vice President. He retired in 2001 and started LGC Consultants LLC.

Abstract:

Microporous and mesoporous carbons are excellent materials for any energy applications. As capacitors, they exhibit high power, a large life cycle, high reliability, and low cost. Coconut shell carbons dominate this market because of their low cost. The large surface areas of these carbons also make them useful in many adsorption and catalytic systems. The pore structure of these carbons allows special selective processes to be carried out such as separation of O₂/N₂, CO₂/H₂O, Butene/Isobutene, and many other processes. The detailed parameters of each process play an important role in the selectivity and effectiveness of the process. In the work presented, some of the most important parameters are discussed for microporous and saran fibers at temperatures from 200C to 1000C. These materials exhibited adsorption characteristics of 4Å and 5Å molecular sieves. Activated diffusion is shown to be the dominant factor for the exclusion of specific molecules. The dynamic size and shape of the molecules determine the observed amount of adsorption at a specific time and temperature. It can be concluded that when the molecular dimensions are close to the size and shape of the pores, the most important factors that determine the observed adsorption are time, temperature, relative pressure, and the diffusion path length.

Biography:

Prof. Manawadevi Y. Udugala-Ganehenege has completed her PhD in 2000 from Wayne State University (WSU), Michigan and postdoctoral studies from Monash University School of Chemistry in Australia. She is currently a professor in Inorganic Chemistry of University of Peradeniya, Sri Lanka. Her main research interest is on utilization of carbon dioxide and bio-waste for renewable energy. She has received numerous prestigious fellowships and awards for her academic excellence and research, including 2000  Esther and Stanley Kirshner Graduate Award and 1995-Thomas Rumble Fellowship from WSU, 2011- Endeavour Awards from Australian government, and 2016 and 2017 Presidential  Awards from Sri Lankan government.

Abstract:

Magnetic and electrochemical studies of face-to–face arranged, tetraaza-macrocyclic homo-bimetallic (Metal= Ni, Cu) complexes revealed a significant affinity towards halide ions, and an interesting metal-metal interaction through a halide bridge. With an intention for finding a solution to reduce the environmental pollution caused by CO₂ emission, I studied the ability of these metal complexes to utilize CO₂ electochemically. The outcome of this attempt ultimately revealed that these complexes were better electro-catalysts for the conversion of very inert CO₂ into useful chemicals such as carbonates and oxalates.

By integrating the knowledge on electrocatalytic activity of these metal complexes to utilize CO₂, a novel Al³⁺, Fe³⁺ modified graphene oxide composite (GO) was synthesized with an intention to apply it as a heterogeneous catalyst for the pre-esterification of the bio-oil containing a high level of free fatty acids (FFA). These GO composite had shown a very efficient capacity for the pre-esterification of FFA. It showed 92.72 % conversion of stearic acid into methyl stearate and 95.37 % reduction of FFA content of Calophyllum inophyllum oil. The conversion was conducted under mild reaction conditions. The optimum catalytic dose, reaction time and temperature employed were of 8% (wt.), 3 h and 65 ⁰C, respectively. The catalyst could be easily recovered and reused more than four cycles, effectively. The subsequent employment of pre-esterified Calophyllum inophyllum oil produced biodiesel with 86% yield without encountering unnecessary soap formation.

Biography:

George Paskalov has completed his PhD at the age of 24years from Polytechnical University (St Petersburg, Russia). He is CEO of Plasma Microsystem LLC (Los Angeles, CA), a plasma research and development company. He has published more than 100 papers and presentations, and more than 13 patents. He also has been serving as board member for a few more companies.

Abstract:

The lifetime of plasma torch electrodes is critical, however, it is usually limited to 200 hours. Here we report a direct current arc plasma torch with cathode lifetime significantly exceeded 1000 hours. To ensure the electrodes’ long life a process of hydrocarbon gas (propane/butane) dissociation in the electric arc discharge is used. In accordance with this method, atoms and ions of carbon from near-electrode plasma deposit on the active surface of the electrodes and form a carbon condensate in the form of carbon nanotubes. It operates as an “actual” electrode. To realize aforesaid the construction of a plasma torch using air as the plasma forming gas has been developed and tested. For long-term electrode operation, carbon nanotubes are ideal materials. They have high electron emission and are chemically inert at high electric field strengths. Carbon nanotubes’ conductivity is superior to all conventional conductors, they can withstand current density 100 times greater than metals, and they have high heat conductivity. They are very mechanically firm, 1000 times more firm than steel and they gain the properties of semiconductors at their curling or flexion. On the basis of atomic force microscopy, scanning electron microscopy, transmission electron microscopy and Raman-spectroscopy investigation it was concluded that the cathode condensate consists mainly of single and multi-walled carbon nanotubes and other nanoforms. The lifetime of the reported cathode totals more than 1000 hours. The experiments reported here confirm the possibility for an unlimited lifetime of the cathode coated with composite nanocarbon layer.

Biography:

Professor Eimutis Juzeliiūnas is the principal research associate at the Centre for Physical Sciences and Technology in Vilnius, Lithuania. His recent research areas include silicon electrochemistry for energy applications, environmental and microbiological degradation of metallic materials, PVD alloys, molten salt electrochemistry. The research leading to these results has received funding from the European Commission 7^th Framework Programme under grant agreement PIOF-GA-300501.

Abstract:

Carbon-silicon compositions are promising to improve light harvesting performance of silicon-based solar cells. Silicon modification by carbon species could increase light absorbance and accelerate photoelectron generation. Procedures of chemical or physical vapor deposition as well as various etchings are typically used to improve antireflection performance of silicon surface. Most of these techniques, however, are not cost effective and also include hazardous reactants. We demonstrate an environmentally friendly electrochemical method of silicon surface modification by a carbon-carbide system in molten calcium chloride. Silicon-carbon-carbide compositions were obtained by polarizing silicon-silica precursor in molten calcium chloride electrolyte using a graphite anode. A reaction scheme is discussed, which includes release of oxygen from silica, its interaction with a graphite electrode and reduction of carbon dioxide by calcium metal. Structure and composition of the structures have been studied by EDX, XRD, and XPS. Semiconductor properties of the structures have been studied by Mott-Schottky characteristics, EIS and photo electrochemistry. High photoactivity of the structures is demonstrated. The surfaces absorbed over 90% of white light in a broad region of wavelengths from 400 nm to 1100 nm. The proposed method offers new opportunities for production of carbon-modified silicon surfaces with superior antireflection and protective properties for solar devices, photoelectrodes, sensors and catalytic supports.

Biography:

Carmen Greice Renda is pursuing her PhD in the Federal University of Sao Carlos. She is a civil engineer with a master in Materials Science and Engineering. She has published papers in reputed journals and has been working with polymers and ceramics materials

Abstract:

Carbonaceous materials have been promised to sensors, biomedicine, magnetic data storage, etc. Nowadays the studies about catalytic graphitization of phenolic resins with several graphitization agents (as ferrocene, boron oxide, graphite, etc.) have been increased. Depending on these materials synthesis it is possible to obtain many types of products as MWNT with the iron particles, nano-shell, and onion-like-carbon structures. This work is intended to see the effects of increasing temperature during the catalytic graphitization of phenolic resins with the ferrocene decomposition. The structure, the properties, the graphitization level and the phases formed are observed by ¹³C-NMR, Raman, X-Ray Diffraction, Impedance and ⁵⁷Fe-Mossbauer Spectroscopies, Electron Paramagnetic Resonance (EPR) and Magnetic Hysteresis. The results ¹³C-NMR, Raman, X-Ray Diffraction and Impedance Spectroscopy are confirmed the graphitization level is increased during the ferrocene decomposition forming a multi-phases material and the iron phases impacts in the percolation electrical threshold. The EPR is demonstrated the ions interaction Fe+3 pulled out of the material. The ⁵⁷Fe-Mossbauer Spectroscopy are concluded the most part of the iron phases is composed by hematite and maghemite. The magnetic hysteresis is evidenced by the ferromagnetic properties.