Download or read book Optimization of Thermoelectric Chalcogenides written by Mohamed Oudah and published by . This book was released on 2014 with total page 107 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thermoelectric (TE) materials can convert heat into electricity when a temperature gradient is applied (Seebeck effect), and can pump heat from the cold end to the hot end using electricity (Peltier effect). These materials have shown improved properties in recent years, and promising bulk materials have been uncovered by many research groups. Chalcogenide containing materials are the leading TEs today, and examples uncovered by the Kleinke group include Tl4(Zr,Hf)Te4, Ba3Cu16-xS11-yTey, and BaCu6-x(S,Se)Te6. Initial evaluation of cold-pressed pellets of these materials showed potential for TE application, with a high figure-of-merit, zT, which relates to the efficiency of a material in converting heat into electricity. This zT is a dimensionless figure composed of heat and electrical transport properties of a material through the equation: zT= T[alpha]^2 [sigma][kappa]^-1, where [alpha] is the Seebeck coefficient, [sigma] the electrical conductivity, and [kappa] the thermal conductivity, measured at a specific temperature (T). A zT value above unity is desired for a bulk material to be used for power generation. The biggest challenge in optimizing TE materials is decoupling the properties contributing to zT, and tuning the properties in a way that improves the zT overall. In this work, it is demonstrated that the zT value for a material can be improved through doping and hot pressing to close to ideal density. Adding Nb to Tl4ZrTe4 improved the zT compared to the ternary sample by enhancing the electrical conductivity. The zT of the samples of nominal composition "Tl4ZrNb0.04Te4" and Tl4Zr1.03Te4 amounted to 0.064 and 0.042 at ~500 K, respectively. Properties of undoped Tl4HfTe4 were also compared to those of Tl4Zr1.03Te4, and Tl4HfTe4 had a higher zT of 0.08 at ~480 K, which is however still too low for any application. Varying the x and y values in Ba3Cu16-xS11-yTey achieved the highest zT for Ba3Cu15.1S8Te3, amounting to 0.78 at ~780 K. However, after six repeat electrical property measurements, these samples showed color change, which was confirmed, via EDX measurement, to be the result of Cu atoms migrating across the material. In contrast, BaCu6-x(S,Se)Te6 showed great stability after repeat measurements, which is attributed to localized mobility of Cu atoms. The properties of BaCu6-x(S,Se)Te6 were measured, and zT values of 0.52 at 580 K and 0.81 at 600 K were obtained for BaCu5.9STe6 and BaCu5.9SeTe6, respectively.

Download or read book Synthesis and Optimization of Chalcogenides Quantum Dots Thermoelectric Materials written by Chong Xiao and published by Springer. This book was released on 2016-02-29 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis focuses on chalcogenide compound quantum dots with special crystal structures and behaviors in an effort to achieve the synergistic optimization of electrical and thermal transport for high-efficiency thermoelectric materials. The controllability and large-scale synthesis of chalcogenide quantum dots are realized through simple colloid synthesis, and the synergistic optimization of the materials’ electrical and thermal transport properties is successfully achieved. Furthermore, the book explores the mechanism involved in the integration of high thermoelectric performance and reversible p-n semiconducting switching in bimetal chalcogenide semiconductors. As such, the thesis will be of interest to university researchers and graduate students in the materials science, chemistry and physics.

Download or read book Optimizing Thermoelectric Properties of Metal Chalcogenides by Engineering Composition and Crystallinity written by Ji Won Kim and published by . This book was released on 2015 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt: Metal Chalcogenide nanostructures have been extensively implemented for high-performance thermoelectric applications, which can directly convert waste-heat-energy into electricity, with the support of theoretical and empirical results. In fact, finding a novel and cost effective synthesis approach that facilitates the formation of stable and reproducible nanostructured thermoelectric materials determines the commercial applicability.

Download or read book Nanostructured Thermoelectric Chalcogenides written by Javier Gainza and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Thermoelectric materials are outstanding to transform temperature differences directly and reversibly into electrical voltage. Exploiting waste heat recovery as a source of power generation could help towards energy sustainability. Recently, the SnSe semiconductor was identified, in single-crystal form, as a mid-temperature thermoelectric material with record high figure of merit, high power factor and surprisingly low thermal conductivity. We describe the preparation of polycrystals of alloys of SnSe obtained by arc-melting; a rapid synthesis that results in strongly nanostructured samples with low thermal conductivity, advantageous for thermoelectricity, approaching the amorphous limit, around 0.3-0.5 W/mK. An initial screening of novel samples Sn1−xMxSe, by alloying with 3d and 4d transition metals such as M = Mn, Y, Ag, Mo, Cd or Au, provides for a means to optimize the power factor. M=Mo, Ag, with excellent values, are described in detail with characterization by x-ray powder diffraction (XRD), scanning electron microscopy (SEM), and electronic and thermal transport measurements. Rietveld analysis of XRD data demonstrates near-perfect stoichiometries of the above-mentioned alloys. SEM analysis shows stacking of nanosized sheets, with large surfaces parallel to layered slabs. An apparatus was developed for the simultaneous measurement of the Seebeck coefficient and electric conductivity at elevated temperatures.

Download or read book Thermoelectrics written by N. M. Ravindra and published by Springer. This book was released on 2018-08-29 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a concise but comprehensive introduction to the fundamentals and current state of the art in thermoelectrics. Addressing an audience of materials scientists and engineers, the book covers theory, materials selection, and applications, with a wide variety of case studies reflecting the most up-to-date research approaches from the past decade, from single crystal to polycrystalline form and from bulk to thin films to nano dimensions. The world is facing major challenges for finding alternate energy sources that can satisfy the increasing demand for energy consumption while preserving the environment. The field of thermoelectrics has long been recognized as a potential and ideal source of clean energy. However, the relatively low conversion efficiency of thermoelectric devices has prevented their utility on a large scale. While addressing the need for thermal management in materials, device components, and systems, thermoelectrics provides a fundamental solution to waste heat recovery and temperature control. This book summarizes the global efforts that have been made to enhance the figure of merit of various thermoelectric materials by choosing appropriate processes and their influence on properties and performance. Because of these advances, today, thermoelectric devices are found in mainstream applications such as automobiles and power generators, as opposed to just a few years ago when they could only be used in niche applications such as in aeronautics, infrared imaging, and space. However, the continued gap between fundamental theoretical results and actual experimental data of figure of merit and performance continues to challenge the commercial applications of thermoelectrics. This book presents both recent achievements and continuing challenges, and represents essential reading for researchers working in this area in universities, industry, and national labs.

Download or read book CRC Handbook of Thermoelectrics written by D.M. Rowe and published by CRC Press. This book was released on 2018-12-07 with total page 720 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thermoelectrics is the science and technology associated with thermoelectric converters, that is, the generation of electrical power by the Seebeck effect and refrigeration by the Peltier effect. Thermoelectric generators are being used in increasing numbers to provide electrical power in medical, military, and deep space applications where combinations of their desirable properties outweigh their relatively high cost and low generating efficiency. In recent years there also has been an increase in the requirement for thermoelectric coolers (Peltier devices) for use in infrared detectors and in optical communications. Information on thermoelectrics is not readily available as it is widely scattered throughout the literature. The Handbook centralizes this information in a convenient format under a single cover. Sixty of the world's foremost authorities on thermoelectrics have contributed to this Handbook. It is comprised of fifty-five chapters, a number of which contain previously unpublished material. The contents are arranged in eight sections: general principles and theoretical considerations, material preparation, measurement of thermoelectric properties, thermoelectric materials, thermoelectric generation, generator applications, thermoelectric refrigeration, and applications of thermoelectric cooling. The CRC Handbook of Thermoelectrics has a broad-based scope. It will interest researchers, technologists, and manufacturers, as well as students and the well-informed, non-specialist reader.

Download or read book Electronic Structure and Thermoelectric Properties on Narrow Band Gap Chalcogenides written by Daniel Bilc and published by . This book was released on 2005 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book New Arsenides and Antimonides as Thermoelectric Materials and Chalcogenides with Distorted Square Nets written by Hong Xu and published by . This book was released on 2010 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thermoelectric (TE) materials can be ranked by their figure-of-merit, ZT, which is defined as ZT = (S2[sigma]T)/[kappa]. Herein, T is the average temperature between the cold (TC) and hot sides (TH) of the thermoelectric device, S is the Seebeck coefficient, [sigma] and [kappa] are electrical and thermal conductivity, respectively. Presently, the applications of TE devices are limited by their low energy conversion efficiencies. The energy conversion efficiency includes the Carnot term [(TH-TC)/TC], an unattainable upper limit of efficiency for any real system, and a loss term, which depends on the ZT value. A larger temperature difference will produce a larger Carnot efficiency, and a higher ZT value will improve the loss efficiency. Thus, the combination of a larger temperature difference and higher ZT will lead to higher energy conversion efficiency, e.g. with ZT = 1, TH = 1000 K, TC = 300K, the efficiency can reach 17%. It is therefore important to explore TE materials that can be used at high temperatures (around 1000 K). Unfortunately there are very few materials that are stable and efficient under such strict conditions. Our group commenced an investigation of the Ir3Ge7 family materials in the late 1990s. My thesis work had been focused on the synthesis and optimization of Mo3Sb7-xTex and Re3(Si, Ge, Sn, Pb)xAs7-x, the ternary substitution variants of Mo3Sb7 and Re3As7.

Download or read book Applications of Laser Ablation written by Dongfang Yang and published by BoD – Books on Demand. This book was released on 2016-12-21 with total page 430 pages. Available in PDF, EPUB and Kindle. Book excerpt: Laser ablation refers to the phenomenon in which a low wavelength and short pulse (ns-fs) duration of laser beam irradiates the surface of a target to induce instant local vaporization of the target material generating a plasma plume consisting of photons, electrons, ions, atoms, molecules, clusters, and liquid or solid particles. This book covers various aspects of using laser ablation phenomenon for material processing including laser ablation applied for the deposition of thin films, for the synthesis of nanomaterials, and for the chemical compositional analysis and surface modification of materials. Through the 18 chapters written by experts from international scientific community, the reader will have access to the most recent research and development findings on laser ablation through original research studies and literature reviews.

Download or read book Thermoelectrics Handbook written by D.M. Rowe and published by CRC Press. This book was released on 2018-10-03 with total page 1008 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ten years ago, D.M. Rowe introduced the bestselling CRC Handbook of Thermoelectrics to wide acclaim. Since then, increasing environmental concerns, desire for long-life electrical power sources, and continued progress in miniaturization of electronics has led to a substantial increase in research activity involving thermoelectrics. Reflecting the latest trends and developments, the Thermoelectrics Handbook: Macro to Nano is an extension of the earlier work and covers the entire range of thermoelectrics disciplines. Serving as a convenient reference as well as a thorough introduction to thermoelectrics, this book includes contributions from 99 leading authorities from around the world. Its coverage spans from general principles and theoretical concepts to material preparation and measurements; thermoelectric materials; thermoelements, modules, and devices; and thermoelectric systems and applications. Reflecting the enormous impact of nanotechnology on the field-as the thermoelectric properties of nanostructured materials far surpass the performance of conventional materials-each section progresses systematically from macro-scale to micro/nano-scale topics. In addition, the book contains an appendix listing major manufacturers and suppliers of thermoelectric modules. There is no longer any need to spend hours plodding through the journal literature for information. The Thermoelectrics Handbook: Macro to Nano offers a timely, comprehensive treatment of all areas of thermoelectrics in a single, unified reference.

Download or read book New Multi functional Chalcogenides for Photovoltaic and Thermoelectric Materials written by Jaeseok Heo and published by . This book was released on 2014 with total page 121 pages. Available in PDF, EPUB and Kindle. Book excerpt: The subject of this PhD thesis is part of a research domain of great present interest in new semiconductor materials for photovoltaic and thermoelectric applications. This domain contains the elaboration and the study of both Cu-based chalcogenides bulk and thin-film samples, driven by materials design principles. One of the most research semiconductor materials is the synthetic mineral tetrahedrite, typified by Cu12Sb4S13. Optical, electrical, and thermal properties have been tuned via chemical substitutions, allowing optimization of performance toward the realizations of high-efficiency devices. Chapter 2 and 3 detail exploration of several tetrahedrite-derivatives for PV and TE applications, respectively. This work demonstrates that this exceptional multi-functionality is related to the unique structural building blocks of these materials. In the context of similar structural features, Cu3-V-VI4 (V = P, As, Sb; VI = S, Se) has been discovered as new absorbers in Chapter 4. Chapter 5 attempts to find the missing Co2GeS4 compound through (Fe, Co)2GeS4 and (Co, Zn)2GeS4 solid solutions by a systematic investigation between theoretical prediction and experimental results. More generally, this fundamental research creates a practical framework for future design principles based search and discovery of effective materials.

Download or read book Computational Intelligence based Optimization of Manufacturing Process for Sustainable Materials written by Deepak Sinwar and published by CRC Press. This book was released on 2023-09-25 with total page 223 pages. Available in PDF, EPUB and Kindle. Book excerpt: The text comprehensively discusses computational models including artificial neural networks, agent-based models, and decision field theory for reliability engineering. It will serve as an ideal reference text for graduate students and academic researchers in the fields of industrial engineering, manufacturing engineering, computer engineering, and materials science. Discusses the development of sustainable materials using metaheuristic approaches. Covers computational models such as agent-based models, ontology, and decision field theory for reliability engineering. Presents swarm intelligence methods such as ant colony optimization, particle swarm optimization, and grey wolf optimization for solving the manufacturing process. Include case studies for industrial optimizations. Explores the use of computational optimization for reliability and maintainability theory. The text covers swarm intelligence techniques including ant colony optimization, particle swarm optimization, cuckoo search, and genetic algorithms for solving complex industrial problems of the manufacturing industry as well as predicting reliability, maintainability, and availability of several industrial components.

Download or read book Chalcogenide written by Xinyu Liu and published by Woodhead Publishing. This book was released on 2019-11-14 with total page 398 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chalcogenide: From 3D to 2D and Beyond reviews graphene-like 2D chalcogenide systems that include topological insulators, interesting thermoelectric structures, and structures that exhibit a host of spin phenomena that are unique to 2D and lower-dimensional geometries. The book describes state-of-the-art materials in growth and fabrication, magnetic, electronic and optical characterization, as well as the experimental and theoretical aspects of this family of materials. Bulk chalcogenides, chalcogenide films, their heterostructures and low-dimensional chalcogenide-based quantum structures are discussed. Particular attention is paid to findings that are relevant to the continued search for new physical phenomena and new functionalities. Finally, the book covers the enormous opportunities that have emerged as it has become possible to achieve lower-dimensional chalcogenide structures by epitaxial techniques. Provides readers with foundational information on the materials growth, fabrication, magnetic, electronic and optical characterization of chalcogenide materials Discusses not only bulk chalcogenides and chalcogenide thin films, but also two-dimensional chalcogenide materials systems Reviews the most important applications in optoelectronics, photovoltaics and thermoelectrics

Download or read book Thermoelectric Materials written by Enrique Macia and published by CRC Press. This book was released on 2015-05-05 with total page 355 pages. Available in PDF, EPUB and Kindle. Book excerpt: Environmental and economic concerns have significantly spurred the search for novel, high-performance thermoelectric materials for energy conversion in small-scale power generation and refrigeration devices. This quest has been mainly fueled by the introduction of new designs and the synthesis of new materials. In fact, good thermoelectric material

Download or read book Applications of Chalcogenides S Se and Te written by Gurinder Kaur Ahluwalia and published by Springer. This book was released on 2018-06-23 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book introduces readers to a wide range of applications for elements in Group 16 of the periodic table, such as, optical fibers for communication and sensing, X-ray imaging, electrochemical sensors, data storage devices, biomedical applications, photovoltaics and IR detectors, the rationale for these uses, the future scope of their applications, and expected improvements to existing technologies. Following an introductory section, the book is broadly divided into three parts—dealing with Sulfur, Selenium, and Tellurium. The sections cover the basic structure of the elements and their compounds in bulk and nanostructured forms; properties that make these useful for various applications, followed by applications and commercial products. As the global technology revolution necessitates the search for new materials and more efficient devices in the electronics and semiconductor industry, Applications of Chalcogenides: S, Se, and Te is an ideal book for a wide range of readers in industry, government and academic research facilities looking beyond silicon for materials used in the electronic and optoelectronic industry as well as biomedical applications.

Download or read book Electron Transport in Compound Semiconductors written by B.R. Nag and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 476 pages. Available in PDF, EPUB and Kindle. Book excerpt: Discovery of new transport phenomena and invention of electron devices through exploitation of these phenomena have caused a great deal of interest in the properties of compound semiconductors in recent years. Extensive re search has been devoted to the accumulation of experimental results, par ticularly about the artificially synthesised compounds. Significant ad vances have also been made in the improvement of the related theory so that the values of the various transport coefficients may be calculated with suf ficient accuracy by taking into account all the complexities of energy band structure and electron scattering mechanisms. Knowledge about these deve lopments may, however, be gathered only from original research contributions, scattered in scientific journals and conference proceedings. Review articles have been published from time to time, but they deal with one particular material or a particular phenomenon and are written at an advanced level. Available text books on semiconductor physics, do not cover the subject in any detail since many of them were written decades ago. There is, there fore, a definite need for a book, giving a comprehensive account of electron transport in compound semiconductors and covering the introductory material as well as the current work. The present book is an attempt to fill this gap in the literature. The first chapter briefly reviews the history of the developement of compound semiconductors and their applications. It is also an introduction to the contents of the book.

Download or read book Lead Chalcogenides written by D. Khokhlov and published by CRC Press. This book was released on 2002-11-15 with total page 720 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lead Chalcogenides remain one of the basic materials of modern infrared optoelectronics. This volume presents the [roperties of lead chalcogenides, including the basic physical features, the bulk and epitaxial growth technique, and the 2-D physics of lead chalcogenide-based structures. In addition, the theoretical appraoches for band structure and impurity state calculations are reviewed.