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 Synthesis and Characterization of Zintl Phases for Thermoelectric Applications written by Tanghong Yi and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A high efficiency thermoelectric material requires being a "phonon glass -electron crystal". Zintl phase compounds can be engineered to combine a "phonon glass" with an "electron crystal" by selectively doping the system to optimize the electronic properties. Current research on thermoelectrics is concentrated on (I) chemical or physical changes to improve the existing materials such as doping and reducing particle size to nano-size and (II) new materials with superior thermoelectric properties. Chapters 2 and 3 have been focused on tuning the transport properties of existing materials to improve the thermoelectric performance. In chapters 4 and 5, new Zintl phases have been synthesized and investigated with respect to their thermoelectric properties. In chapter 2, silicon nanoparticles embedded Mg2Si/xSi nanocomposites have been synthesized at 623 K from MgH2 and Bi containing Si nanoparticle powders. This synthetic route avoids the production of oxides and lowers the formation temperature of Mg2Si. It also provides a route to homogeneously mixed Si nanoparitcles within a Mg2Si matrix. Powder X-ray diffraction (XRD), thermogravimetry/differential scanning calorimetry (TG/DSC), electron microprobe analysis (EMPA), and scanning transmission electron microscopy (STEM) are applied to characterize the phase and micro-structure. Thermoelectric properties measurements indicate that the thermal conductivity is reduced by a small amount of Si nano-inclusions, which is in agreement of our theoretical calculations. A dimensionless figure of merit zT ~ 0.7 is obtained at 775 K for 1% Bi doped Mg2Si/x Si with x = 0 and 2.5 mol.%. In chapter 3, magnetic and transport properties of a series of Te doped Yb14MnSb11 samples prepared by Sn flux method have been studied. Increasing amounts of Te increases the saturation moment of Yb14MnSb11−(x)Te(x) and magnetoresistence effect. Both Seebeck coefficient and electrical resistivity increase with increasing amount of Te as a result of decreasing carrier concentration. Approximately 12% improvement of zT has achieved for x = 0.07 at 1240 K. Thermoelectric properties of the compounds Yb11MSb9 (M = Ga, In) via self-flux synthesis, closely structure related to Yb14MnSb11, have been investigated in chapter 4. Particularly low lattice thermal conductivity values, less than 0.6 W/m*K, are obtained for both compounds. The low lattice thermal conductivity suggests that Yb11MSb9 (M = Ga, In) has the potential for high thermoelectric efficiency at high temperature if charge carrier doping can be optimized. A two-step solid-state method is developed to fabricate two rare-earth containing ternary phosphides, Eu3Ga2P4 and Eu3In2P4, and their thermoelectric properties are investigated in chapter 5. The powder XRD and TG-DSC are employed to characterize the phase purity and thermal stability. Electronic structures of both compounds are calculated and provide band-gaps of 0.60 and 0.29 eV for Eu3Ga2P4 and Eu3In2P4, respectively. Transport properties measurements suggest that these Zintl phosphides have the potential to be good high temperature thermoelectric materials with optimization of the charge carrier concentration by appropriate extrinsic dopants.
Download or read book Handbook on the Physics and Chemistry of Rare Earths written by Jean-Claude G. Bunzli and published by Elsevier. This book was released on 2021-10-30 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt: Handbook on the Physics and Chemistry of Rare Earths: Including Actinides, Volume 60 presents the latest release in this continuous series that covers all aspects of rare earth science, including chemistry, life sciences, materials science and physics. - Presents up-to-date overviews and new developments in the field of rare earths, covering both their physics and chemistry - Contains individual chapters that are comprehensive and broad, along with critical reviews - Provides contributions from highly experienced, invited experts
Download or read book Synthesis and Characterization of Two Unusual Zintl Phases written by Ara Cho and published by . This book was released on 2004 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Thermoelectric Energy Conversion written by Ryoji Funahashi and published by Woodhead Publishing. This book was released on 2021-01-19 with total page 732 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thermoelectric Energy Conversion: Theories and Mechanisms, Materials, Devices, and Applications provides readers with foundational knowledge on key aspects of thermoelectric conversion and reviews future prospects. Sections cover the basic theories and mechanisms of thermoelectric physics, the chemical and physical aspects of classical to brand-new materials, measurement techniques of thermoelectric conversion properties from the materials to modules and current research, including the physics, crystallography and chemistry aspects of processing to produce thermoelectric devices. Finally, the book discusses thermoelectric conversion applications, including cooling, generation, energy harvesting, space, sensor and other emerging areas of applications. - Reviews key applications of thermoelectric energy conversion, including cooling, power generation, energy harvesting, and applications for space and sensing - Discusses a wide range of materials, including skutterudites, heusler materials, chalcogenides, oxides, low dimensional materials, and organic materials - Provides the fundamentals of thermoelectric energy conversion, including the physics, phonon conduction, electronic correlation, magneto-seebeck theories, topological insulators and thermionics
Download or read book Synthesis and Characterization of 14 1 11 Ytterbium Manganese Antimonide Derivatives for Thermoelectric Applications written by Kurt Star and published by . This book was released on 2013 with total page 109 pages. Available in PDF, EPUB and Kindle. Book excerpt: Yb14MnSb11 is a promising thermoelectric material for high temperature applications with values of the non-dimensional figure of merit ZT peaking at 1.4 above 1200 K. Yb14MnSb11 exhibits low lattice thermal conductivity values and a p-type semimetallic behavior. This compound is a member of a large family of Zintl phases with a "14-1-11" A14MPn11 stoichiometry (Pn = As, Sb, Bi; A = Ca, La, Sr, Yb, Eu; M = Mn, Al, Cd, Ga, In, Nb, Zn). There is significant interest in investigating how substitutions on any of the atomic sites impact the band gap, lattice thermal conductivity and charge carrier concentration and mobility. High energy ball milling is shown here to be a convenient method of synthesis to prepare Yb14MnSb11 and solid solution systems derived from this compound by substitution of elements. Here compositions in the Yb14Mn1-xAlxSb11-yBiy, Yb14MnSb11-yAsy, Yb14-xCaxMnSb11, Yb14-xLaxMnSb11 and Yb14-xNaxAlSb11 systems are considered. Characterization of the synthesized compositions was done by X-ray diffraction, electron microprobe. High temperature measurements of the electrical and thermal transport properties were carried out up to 1275 K. The experimental results on solid solution samples are compared to that of pure Yb14MnSb11 samples prepared by the same synthesis technique. A single parabolic band degenerate Fermi statistical model was used to estimate various properties such as effective mass. Calculated lattice thermal conductivity in solid solutions was also compared to various models. Though some increase in ZT was calculated below 900K, none of the derivatives studied were calculated to have a averge ZT significantly higher than Yb14MnSb11.
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 Synthesis and Characterization of Ternary Zintl Phases written by Weir-Mirn Hurng and published by . This book was released on 1988 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Tuning the Transport Properties of Zintl Phases for Thermoelectric Applications written by Japheth Frank Rauscher and published by . This book was released on 2008 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Solid State Physics written by S. L. Chaplot and published by Alpha Science Int'l Ltd.. This book was released on 2002 with total page 726 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume covers the proceedings of the 44th Department of Atomic Engineering (DAE) Solid State Physics Symposium.With contributions of papers from institutions from around the world. Contains 316 research articles, including 28 invited papers, on a wide range of topics of current interest in solid state physics comprising the following categories: Phase Transitions Phonons Soft-condensed Matter Electronic Structure Novel Materials Superconductivity Experimental Techniques and Instrumentation Magnetism Liquids, Glasses and Amorphous Systems Transport Properties Relaxation Studies Semiconductor Physics Surface Science Key Features: Recent developments in Synchrotron Research Photo-electron Spectroscopy Newly emerging superconductors
Download or read book Modules Systems and Applications in Thermoelectrics written by David Michael Rowe and published by CRC Press. This book was released on 2012-04-25 with total page 585 pages. Available in PDF, EPUB and Kindle. Book excerpt: Comprising two volumes, Thermoelectrics and Its Energy Harvesting reviews the dramatic improvements in technology and application of thermoelectric energy with a specific intention to reduce and reuse waste heat and improve novel techniques for the efficient acquisition and use of energy. This volume, Modules, Systems and Applications in Thermoelectrics, discusses the practical, novel, and truly groundbreaking applications of thermoelectrics in a range of markets. The book details the U.S. interest in alternative energy and energy harvesting, specifically, the current efforts to use thermoelectric generators (TGs) to reduce emissions. Internationally, it expounds on the strong interest in Japan, Korea and Europe to incorporate TGs in cars to reduce fuel consumption and meet EU carbon dioxide emission targets; the European plans to build an isotopic powered thermoelectric generator; and India’s use of TG s in converting hot water from steel mills into electricity.
Download or read book Advanced Thermoelectrics written by Zhifeng Ren and published by CRC Press. This book was released on 2017-11-06 with total page 790 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides an overview on nanostructured thermoelectric materials and devices, covering fundamental concepts, synthesis techniques, device contacts and stability, and potential applications, especially in waste heat recovery and solar energy conversion. The contents focus on thermoelectric devices made from nanomaterials with high thermoelectric efficiency for use in large scale to generate megawatts electricity. Covers the latest discoveries, methods, technologies in materials, contacts, modules, and systems for thermoelectricity. Addresses practical details of how to improve the efficiency and power output of a generator by optimizing contacts and electrical conductivity. Gives tips on how to realize a realistic and usable device or module with attention to large scale industry synthesis and product development. Prof. Zhifeng Ren is M. D. Anderson Professor in the Department of Physics and the Texas Center for Superconductivity at the University of Houston. Prof. Yucheng Lan is an associate professor in Morgan State University. Prof. Qinyong Zhang is a professor in the Center for Advanced Materials and Energy at Xihua University of China.
Download or read book Encyclopedia of the Alkaline Earth Compounds written by Richard C. Ropp and published by Newnes. This book was released on 2012-12-31 with total page 1201 pages. Available in PDF, EPUB and Kindle. Book excerpt: Encyclopedia of the Alkaline Earth Compounds is a compilation describing the physical and chemical properties of all of the alkaline earth compounds that have been elucidated to date in the scientific literature. These compounds are used in applications such as LEDs and electronic devices such as smart phones and tablet computers. Preparation methods for each compound are presented to show which techniques have been successful. Structures and phase diagrams are presented where applicable to aid in understanding the complexities of the topics discussed. With concise descriptions presenting the chemical, physical and electrical properties of any given compound, this subject matter will serve as an introduction to the field. This compendium is vital for students and scientific researchers in all fields of scientific endeavors, including non-chemists. 2013 Honorable Mention in Chemistry & Physics from the Association of American Publishers' PROSE Awards Presents a systematic coverage of all known alkaline earth inorganic compounds and their properties Provides a clear, consistent presentation based on groups facilitatating easy comparisons Includes the structure of all the compounds in high quality full-color graphics Summarizes all currently known properties of the transition metals compounds Lists the uses and applications of these compounds in electronics, energy, and catalysis
Download or read book Advanced Thermoelectrics written by Zhifeng Ren and published by CRC Press. This book was released on 2017-11-06 with total page 1102 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides an overview on nanostructured thermoelectric materials and devices, covering fundamental concepts, synthesis techniques, device contacts and stability, and potential applications, especially in waste heat recovery and solar energy conversion. The contents focus on thermoelectric devices made from nanomaterials with high thermoelectric efficiency for use in large scale to generate megawatts electricity. Covers the latest discoveries, methods, technologies in materials, contacts, modules, and systems for thermoelectricity. Addresses practical details of how to improve the efficiency and power output of a generator by optimizing contacts and electrical conductivity. Gives tips on how to realize a realistic and usable device or module with attention to large scale industry synthesis and product development. Prof. Zhifeng Ren is M. D. Anderson Professor in the Department of Physics and the Texas Center for Superconductivity at the University of Houston. Prof. Yucheng Lan is an associate professor in Morgan State University. Prof. Qinyong Zhang is a professor in the Center for Advanced Materials and Energy at Xihua University of China.
Download or read book Thermoelectric Materials and Devices written by Iris Nandhakumar and published by Royal Society of Chemistry. This book was released on 2017 with total page 269 pages. Available in PDF, EPUB and Kindle. Book excerpt: Authoritative account of recent developments in thermoelectric materials and devices for power energy harvesting applications, ideal for researchers and industrialists in materials science.
Download or read book Chemistry Structure and Bonding of Zintl Phases and Ions written by Susan Mary Kauzlarich and published by VCH Publishers. This book was released on 1996 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt: Seven chapters report current research into the phases and ions of a class of compounds that are electronically positioned between the intermetallic compounds and insulating valence compounds. They cover structure and bonding at the Zintl border, structural patterns of homo- and hetero-nuclear anions and related intermetallic compounds and concepts for interpreting them, the early p-block elements, polyanions in liquid ionic alloys, molecular transition metal complexes, transition metal compounds, and synthesizing and characterizing intermetallic materials using Zintl phases as precursors. An introduction surveys the life and work of German chemist Eduard Zintl (1898-1941). Annotation copyright by Book News, Inc., Portland, OR
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.
