Download or read book Synthesis and Physical Characterization of Thermoelectric Single Crystals written by Juan Pablo Porras Pérez Guerrero and published by . This book was released on 2012 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt: There is much current interest in thermoelectric devices for sustainable energy. This thesis describes a research project on the synthesis and physical characterization of thermoelectric single crystals. 1In4Se3-[delta] crystals were grown by different methods including the use of a floating zone furnace and a three-zone furnace, as well as different initial compositions. The samples obtained each time, either crystalline or powder, were analyzed using x-ray diffraction to find the phases present, and orientations in the case of crystals. The crystals were studied by the means of neutron scattering at Oak Ridge National Laboratory, and the results presented differences from previous literature reports and a non-zero intensity of forbidden Bragg peaks was noted. Simulations of the effect of Se vacancies in the crystal were executed to explore this last phenomenon. Measurements of the electrical resistivity p and Seebeck coefficient S of the crystal related to the figure of merit ZT = S2T/pk were compared with the values presented by other groups.
Download or read book Single Crystal Growth and Characterization of Zintl Phase Thermoelectric Compounds written by David M. Smiadak and published by . This book was released on 2020 with total page 177 pages. Available in PDF, EPUB and Kindle. Book excerpt: Zintl phases have been the focus of recent thermoelectric research due to their complex crystal structures, which include covalently bonded anionic sub-structures in a lattice of electropositive cations. The covalent bonds lead to high mobility, while strict electron-counting rules contribute to the formation of complex structures, which in turn lead to low thermal conductivity. In this manner,these compounds can fit the ideal phonon-glass and electron-crystal model for thermoelectric materials. Although Zintl phases are a promising class of thermoelectric materials that have been studied intensively since 2005, there are still several important fundamental questions that remain unanswered. These include questions related to anisotropic transport and how it relates to the crystalstructure, and the role played by intrinsic defects in determining carrier concentration. Additionally, the field of Zintl compounds is ever expanding; through the use of exploratory single crystal growths and the careful selection of starting composition, novel compounds and structure types can be discovered that may be promising thermoelectric candidates.Zintls with the Ca5M2Sb6 (M = Al, Ga, In) structure type, characterized by one-dimensional, ladder-like polyanions, were previously predicted to have highly anisotropic electrical conductivity. To investigate this anisotropic behavior, single crystals of Ca5M2Sb6 (M = Al, Ga, In) were grown in the current work via the self-flux method. These crystals grew preferentially along the polyanionic "ladders" of the structure, but only measured a few millimeters long by tens of microns thick. Characterizing the transport properties of these crystals both parallel and perpendicular to the growth direction demanded a novel characterization technique, as placing contacts by hand wasinfeasible in the perpendicular direction. Micro-fabrication techniques will be utilized whereby micro-ribbons are extracted from crystals both perpendicular and parallel to the preferred growth direction using a focused ion beam milling technique. Photolithography was then utilized to create a circuit of sensors for transport measurements. The resistivity, carrier concentration, and mobility of a micro-ribbon of Ca5In2Sb6 perpendicular to the preferred growth direction was successfully characterized using this approach. Resistivity measured in the parallel direction using a four-probe resistivity setup was found to be nearly 20 times higher than the perpendicular direction, confirming theoretical predictions.Experimental investigation of intrinsic defects in single crystals is also explored in the promising Mg3Sb2 system, accomplished using single crystal X-ray diffraction. The defect chemistry of this system for both Mg- and Sb-rich single crystal synthesis is investigated, where vacancies and interstitial sites are identified and quantified in collaboration with researchers at the Max Planck Institute for Chemical Physics of Solids in Dresden, Germany.Lastly, the discovery of a new quaternary Zintl phase, Ca9Zn3.1In0.9Sb9 is reported, which was discovered as a by-product during the attempted growth of Zn-doped Ca5In2Sb6. The new Ca9Zn3.1In0.9Sb9 structure was solved with the help of collaborators at the University of Delaware. Measurements of the electrical resistivity of the Ca9Zn3.1In0.9Sb9 crystals performed at MichiganState University showed results similar to that of already-optimized Ca9Zn4.5Sb9 compounds, pointing to promising thermoelectric performance.
Download or read book Oxide Thermoelectric Materials written by Yuan-Hua Lin and published by John Wiley & Sons. This book was released on 2019-10-28 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first book of its kind?providing comprehensive information on oxide thermoelectrics This timely book explores the latest research results on the physics and materials science of oxide thermoelectrics at all scales. It covers the theory, design and properties of thermoelectric materials as well as fabrication technologies for devices and their applications. Written by three distinguished materials scientists, Oxide Thermoelectric Materials reviews: the fundamentals of electron and phonon transport; modeling of thermoelectric modules and their optimization; synthetic processes, structures, and properties of thermoelectric materials such as Bi2Te3- and skutterudite-based materials and Si-Ge alloys. In addition, the book provides a detailed description of the construction of thermoelectric devices and their applications. -Contains fundamentals and applications of thermoelectric materials and devices, and discusses their near-future perspectives -Introduces new, promising materials and technologies, such as nanostructured materials, perovskites, and composites -Paves the way for increased conversion efficiencies of oxides -Authored by well-known experts in the field of thermoelectrics Oxide Thermoelectric Materials is a well-organized guidebook for graduate students involved in physics, chemistry, or materials science. It is also helpful for researchers who are getting involved in thermoelectric research and development.
Download or read book Synthesis Crystal Growth and Characterization written by K. Lal and published by Elsevier. This book was released on 2012-12-02 with total page 583 pages. Available in PDF, EPUB and Kindle. Book excerpt: Synthesis, Crystal Growth and Characterization presents the proceedings of the International School on Synthesis, Crystal Growth and Characterization of Materials for Energy Conversion and Storage, held on October 12-23, 1981, at the National Physical Laboratory in New Delhi, India. The book consists of lectures by distinguished scientists from around the world who tackle different aspects of synthesis, crystal growth, characterization of materials, energy conversion, and energy storage. Organized into four parts encompassing 26 chapters, the book begins with an overview of the synthesis of materials at high temperatures and pressures before turning to a discussion of how macrocrystalline and amorphous silicon is prepared. It then looks at fundamental principles underlying the process of crystal growth, both from the vapor phase and from melt, and methodically introduces the reader to the different techniques used to characterize materials, including neutron scattering and electron transport. The next chapters focus on point defects and aggregates that influence the critical electronic properties of semiconducting materials, X-ray diffraction studies of strains and stresses in thin films used in solid-state devices, and electron spectroscopic studies of solid surfaces. The book also considers the role of physics in microelectronics and vice versa, fast ion transport in solids, and the concept of Syadvada in relation to modern physics. This volume is a valuable resource for participants of the International School on Synthesis, Crystal Growth and Characterization of Materials for Energy Conversion and Storage, as well as active researchers working in areas related to the field.
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 Synthesis and Characterization of Solid solution Zintl Phases for Thermoelectric Applications written by Catherine Amanda Cox Uvarov and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Thermoelectric devices can convert thermal energy into electrical energy or vice-versa. Zintl phases are a class of materials than can be used in such devices because they often possess complex structures necessary for the desired thermoelectric properties (Seebeck, electrical resistivity, thermal conductivity). In 2006, the Zintl phase Yb14MnSb11 was discovered to have a max zT = 1.0 at 1200 K. There are many known compounds of the generic formula A14MPn11 (A = alkaline earth, Eu, Yb; M = Group 13, Mn, Zn; Pn = P, As, Sb, Bi), however very few of these compounds have been measured for thermoelectric properties. The electronic properties of Yb14MnSb11 can be tuned through chemical substitution to make solid-solutions. This compound is inherently a p-type material with metallic-like conductivity due to a hole on the [Mn2Sb412−h]9− tetrahedral cluster. In order to raise the thermoelectric figure of merit, zT, the carrier concentration needs to be reduced by substituting in elements that donate electrons to the structure and fill the hole. Solid solution series of Yb14Mn1[subscript x]Al[subscript x]Sb11 (x = 0.2, 0.4, 0.6, 0.8, 0.95, 1) and Yb14[subscript x]Ca[subscript x]MnSb11 (x = 2, 4, 6, 8) have been made by Sn-Flux. In a flux reaction, a molten metal (Sn) is used as a solvent. Yb14−[subscript x]Tm[subscript x]MnSb11 was also made by Sn-flux, but the solubility limit of Tm into the structure is around x = 0.4. All of these elements (Al3+, Ca2+, and Tm3+) reduce the carrier concentration. The structure and composition were characterized by single crystal X-ray diffraction, powder X-ray diffraction, and electron microprobe analysis. Other compositions including Yb14−[subscript x]Ca[subscript x]Mn[subscript (1-y)/2]Zn[subscript (1-y)/2]Al[subscript y]Sb11 and Ca14−[subscript x]La[subscript x]AlSb11 were also explored using a Sn-flux synthetic route. The Sn-flux route is an excellent approach to grow pure-phase single crystals, and single crystals are vital for understanding of the structure and properties. However, mechanical alloying would be a better synthetic method for large scale production of material for thermoelectric devices. A method to make Yb14MnSb11 using mechanical alloying of elemental Yb, and Sb, with a MnSb binary was developed. A similar mechanical alloying approach was used to make Eu14MnSb11. Eu14MnSb11 single crystals have not been grown from a flux because Eu10Mn6Sb13 forms as the primary phase. The product from the mechanical alloying synthesis was characterized by powder X-ray diffraction and electron microprobe analysis. Thermoelectric properties up to 1200 K were measured including the Seebeck coefficient, electrical resistivity, and thermal conductivity. Heat capacity measurements of Yb14MnSb11, Yb14Mn1−[subscript x]Al[subscript x]Sb11 and Eu14MnSb11 were used to reevaluate the thermal conductivity. The thermoelectric properties were compared and contrasted to the data measured on a Sn-flux Yb14MnSb11 sample that was published in 2006.
Download or read book Design Synthesis and Characterization of New Materials for Thermoelectric Applications written by Thomas Kent Reynolds and published by . This book was released on 2003 with total page 1132 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Materials Preparation and Characterization in Thermoelectrics written by David Michael Rowe and published by CRC Press. This book was released on 2017-12-19 with total page 555 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book includes updated theoretical considerations which provide an insight into avenues of research most likely to result in further improvements in material performance. It details the latest techniques for the preparation of thermoelectric materials employed in energy harvesting, together with advances in the thermoelectric characterisation of nanoscale material. The book reviews the use of neutron beams to investigate phonons, whose behaviour govern the lattice thermal conductivity and includes a chapter on patents.
Download or read book Bibliography written by Pierre Villars and published by Walter de Gruyter. This book was released on 2012-12-21 with total page 1827 pages. Available in PDF, EPUB and Kindle. Book excerpt: By browsing about 10 000 000 scientific articles of over 200 major journals mainly in a 'cover to cover approach' some 200 000 publications were selected. The extracted data is part of the following fundamental material research fields: crystal structures (S), phase diagrams (also called constitution) (C) and the comprehensive field of intrinsic physical properties (P). This work has been done systematically starting with the literature going back to 1900. The above mentioned research field codes (S, C, P) as well as the chemical systems investigated in each publication were included in the present work. The aim of the Inorganic Substances Bibliography is to provide researchers with a comprehensive compilation of all up to now published scientific publications on inorganic systems in only three handy volumes.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1973 with total page 1040 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Download or read book Journal of Research of the National Bureau of Standards written by United States. National Bureau of Standards and published by . This book was released on 1963 with total page 700 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Synthesis of Single Crystals and Investigation of Physical Properties of Rh based Ternary Stannides written by 曾致維 and published by . This book was released on 2018 with total page 83 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Synthesis and Physical Properties of Group 14 Intermetallic Clathrates written by Stevce Stefanoski and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The search of materials relevant for thermoelectric and magnetocaloric applications, as well as materials that interact with light, is an important aspect of the materials science. Such materials can be used for solid-state power generation and refrigeration, as light sources, detectors, or controllers. Intermetallic clathrates have long been of interest for the materials science research. The promise these materials hold for useful applications ranges from thermoelectrics to photovoltaics and optoelectronics to potentially ultra-hard materials and magnetic cooling applications. Their unique physical properties are intimately related to their intriguing structural properties. Thus a fundamental understanding of the chemistry and physics of inorganic clathrates offers the possibility to assess their potential for use in the various applications mentioned above. In this work the selective, phase pure, single-crystal growth of AxSi46 and AySi136 (A = Na, K) intermetallic clathrates by the new vapor-phase intercalation method is presented. The approach appears promising for accessing regions of the equilibrium diagrams for Na-Si and K-Si clathrates that can be otherwise difficult to reach due to the greatly differing properties of the constituent elements. Physical properties of these materials were investigated in terms of single-crystal diffraction, electrical and thermal properties measurements. The synthesis and structural properties of single crystals of NaxSi136 are presented. A two-step synthetic approach was employed for the synthesis of NaxSi136 which also allowed for low temperature transport measurements of polycrystalline NaxSi136. The potential of the Eu8Ga16Ge30 type-I and VIII - EuO composites for magnetocaloric applications is discussed. The type-I clathrate - EuO composites hold promise for active magnetic refrigeration around 70 K.
Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1975-04 with total page 1082 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Technical Abstract Bulletin written by and published by . This book was released on with total page 912 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book U S Government Research Reports written by and published by . This book was released on 1963 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Materials Preparation and Characterization in Thermoelectrics written by David Michael Rowe and published by CRC Press. This book was released on 2012-04-25 with total page 555 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book includes updated theoretical considerations which provide an insight into avenues of research most likely to result in further improvements in material performance. It details the latest techniques for the preparation of thermoelectric materials employed in energy harvesting, together with advances in the thermoelectric characterisation of nanoscale material. The book reviews the use of neutron beams to investigate phonons, whose behaviour govern the lattice thermal conductivity and includes a chapter on patents.
