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Sample records for thermoelectric materials 1998-the

  1. Thermoelectric materials having porosity

    Science.gov (United States)

    Heremans, Joseph P.; Jaworski, Christopher M.; Jovovic, Vladimir; Harris, Fred

    2014-08-05

    A thermoelectric material and a method of making a thermoelectric material are provided. In certain embodiments, the thermoelectric material comprises at least 10 volume percent porosity. In some embodiments, the thermoelectric material has a zT greater than about 1.2 at a temperature of about 375 K. In some embodiments, the thermoelectric material comprises a topological thermoelectric material. In some embodiments, the thermoelectric material comprises a general composition of (Bi.sub.1-xSb.sub.x).sub.u(Te.sub.1-ySe.sub.y).sub.w, wherein 0.ltoreq.x.ltoreq.1, 0.ltoreq.y.ltoreq.1, 1.8.ltoreq.u.ltoreq.2.2, 2.8.ltoreq.w.ltoreq.3.2. In further embodiments, the thermoelectric material includes a compound having at least one group IV element and at least one group VI element. In certain embodiments, the method includes providing a powder comprising a thermoelectric composition, pressing the powder, and sintering the powder to form the thermoelectric material.

  2. Modelling of thermoelectric materials

    DEFF Research Database (Denmark)

    Bjerg, Lasse

    In order to discover new good thermoelectric materials, there are essentially two ways. One way is to go to the laboratory, synthesise a new material, and measure the thermoelectric properties. The amount of compounds, which can be investigated this way is limited because the process is time...... consuming. Another approach is to model the thermoelectric properties of a material on a computer. Several crystal structures can be investigated this way without use of much man power. I have chosen the latter approach. Using density functional theory I am able to calculate the band structure of a material....... This band structure I can then use to calculate the thermoelectric properties of the material. With these results I have investigated several materials and found the optimum theoretical doping concentration. If materials with these doping concentrations be synthesised, considerably better thermoelectric...

  3. Thermoelectric Energy Conversion: Materials, Devices, and Systems

    International Nuclear Information System (INIS)

    Chen, Gang

    2015-01-01

    This paper will present a discussion of challenges, progresses, and opportunities in thermoelectric energy conversion technology. We will start with an introduction to thermoelectric technology, followed by discussing advances in thermoelectric materials, devices, and systems. Thermoelectric energy conversion exploits the Seebeck effect to convert thermal energy into electricity, or the Peltier effect for heat pumping applications. Thermoelectric devices are scalable, capable of generating power from nano Watts to mega Watts. One key issue is to improve materials thermoelectric figure- of-merit that is linearly proportional to the Seebeck coefficient, the square of the electrical conductivity, and inversely proportional to the thermal conductivity. Improving the figure-of-merit requires good understanding of electron and phonon transport as their properties are often contradictory in trends. Over the past decade, excellent progresses have been made in the understanding of electron and phonon transport in thermoelectric materials, and in improving existing and identify new materials, especially by exploring nanoscale size effects. Taking materials to real world applications, however, faces more challenges in terms of materials stability, device fabrication, thermal management and system design. Progresses and lessons learnt from our effort in fabricating thermoelectric devices will be discussed. We have demonstrated device thermal-to-electrical energy conversion efficiency ∼10% and solar-thermoelectric generator efficiency at 4.6% without optical concentration of sunlight (Figure 1) and ∼8-9% efficiency with optical concentration. Great opportunities exist in advancing materials as well as in using existing materials for energy efficiency improvements and renewable energy utilization, as well as mobile applications. (paper)

  4. Methods of synthesizing thermoelectric materials

    Science.gov (United States)

    Ren, Zhifeng; Chen, Shuo; Liu, Wei-Shu; Wang, Hengzhi; Wang, Hui; Yu, Bo; Chen, Gang

    2016-04-05

    Methods for synthesis of thermoelectric materials are disclosed. In some embodiments, a method of fabricating a thermoelectric material includes generating a plurality of nanoparticles from a starting material comprising one or more chalcogens and one or more transition metals; and consolidating the nanoparticles under elevated pressure and temperature, wherein the nanoparticles are heated and cooled at a controlled rate.

  5. Recent Progress on PEDOT-Based Thermoelectric Materials.

    Science.gov (United States)

    Wei, Qingshuo; Mukaida, Masakazu; Kirihara, Kazuhiro; Naitoh, Yasuhisa; Ishida, Takao

    2015-02-16

    The thermoelectric properties of poly(3,4-ethylenedioxythiophene) (PEDOT)-based materials have attracted attention recently because of their remarkable electrical conductivity, power factor, and figure of merit. In this review, we summarize recent efforts toward improving the thermoelectric properties of PEDOT-based materials. We also discuss thermoelectric measurement techniques and several unsolved problems with the PEDOT system such as the effect of water absorption from the air and the anisotropic thermoelectric properties. In the last part, we describe our work on improving the power output of thermoelectric modules by using PEDOT, and we outline the potential applications of polymer thermoelectric generators.

  6. High Temperature Integrated Thermoelectric Ststem and Materials

    Energy Technology Data Exchange (ETDEWEB)

    Mike S. H. Chu

    2011-06-06

    The final goal of this project is to produce, by the end of Phase II, an all ceramic high temperature thermoelectric module. Such a module design integrates oxide ceramic n-type, oxide ceramic p-type materials as thermoelectric legs and oxide ceramic conductive material as metalizing connection between n-type and p-type legs. The benefits of this all ceramic module are that it can function at higher temperatures (> 700 C), it is mechanically and functionally more reliable and it can be scaled up to production at lower cost. With this all ceramic module, millions of dollars in savings or in new opportunities recovering waste heat from high temperature processes could be made available. A very attractive application will be to convert exhaust heat from a vehicle to reusable electric energy by a thermoelectric generator (TEG). Phase I activities were focused on evaluating potential n-type and p-type oxide compositions as the thermoelectric legs. More than 40 oxide ceramic powder compositions were made and studied in the laboratory. The compositions were divided into 6 groups representing different material systems. Basic ceramic properties and thermoelectric properties of discs sintered from these powders were measured. Powders with different particles sizes were made to evaluate the effects of particle size reduction on thermoelectric properties. Several powders were submitted to a leading thermoelectric company for complete thermoelectric evaluation. Initial evaluation showed that when samples were sintered by conventional method, they had reasonable values of Seebeck coefficient but very low values of electrical conductivity. Therefore, their power factors (PF) and figure of merits (ZT) were too low to be useful for high temperature thermoelectric applications. An unconventional sintering method, Spark Plasma Sintering (SPS) was determined to produce better thermoelectric properties. Particle size reduction of powders also was found to have some positive benefits

  7. Carbon-Nanotube-Based Thermoelectric Materials and Devices

    Energy Technology Data Exchange (ETDEWEB)

    Blackburn, Jeffrey L. [Chemistry and Nanoscience Center, National Renewable Energy Laboratory, Golden CO 80401-3305 USA; Ferguson, Andrew J. [Chemistry and Nanoscience Center, National Renewable Energy Laboratory, Golden CO 80401-3305 USA; Cho, Chungyeon [Department of Mechanical Engineering, Texas A& M University, College Station TX 77843-3003 USA; Grunlan, Jaime C. [Department of Mechanical Engineering, Texas A& M University, College Station TX 77843-3003 USA

    2018-01-22

    Conversion of waste heat to voltage has the potential to significantly reduce the carbon footprint of a number of critical energy sectors, such as the transportation and electricity-generation sectors, and manufacturing processes. Thermal energy is also an abundant low-flux source that can be harnessed to power portable/wearable electronic devices and critical components in remote off-grid locations. As such, a number of different inorganic and organic materials are being explored for their potential in thermoelectric-energy-harvesting devices. Carbon-based thermoelectric materials are particularly attractive due to their use of nontoxic, abundant source-materials, their amenability to high-throughput solution-phase fabrication routes, and the high specific energy (i.e., W g-1) enabled by their low mass. Single-walled carbon nanotubes (SWCNTs) represent a unique 1D carbon allotrope with structural, electrical, and thermal properties that enable efficient thermoelectric-energy conversion. Here, the progress made toward understanding the fundamental thermoelectric properties of SWCNTs, nanotube-based composites, and thermoelectric devices prepared from these materials is reviewed in detail. This progress illuminates the tremendous potential that carbon-nanotube-based materials and composites have for producing high-performance next-generation devices for thermoelectric-energy harvesting.

  8. Carbon-Nanotube-Based Thermoelectric Materials and Devices.

    Science.gov (United States)

    Blackburn, Jeffrey L; Ferguson, Andrew J; Cho, Chungyeon; Grunlan, Jaime C

    2018-03-01

    Conversion of waste heat to voltage has the potential to significantly reduce the carbon footprint of a number of critical energy sectors, such as the transportation and electricity-generation sectors, and manufacturing processes. Thermal energy is also an abundant low-flux source that can be harnessed to power portable/wearable electronic devices and critical components in remote off-grid locations. As such, a number of different inorganic and organic materials are being explored for their potential in thermoelectric-energy-harvesting devices. Carbon-based thermoelectric materials are particularly attractive due to their use of nontoxic, abundant source-materials, their amenability to high-throughput solution-phase fabrication routes, and the high specific energy (i.e., W g -1 ) enabled by their low mass. Single-walled carbon nanotubes (SWCNTs) represent a unique 1D carbon allotrope with structural, electrical, and thermal properties that enable efficient thermoelectric-energy conversion. Here, the progress made toward understanding the fundamental thermoelectric properties of SWCNTs, nanotube-based composites, and thermoelectric devices prepared from these materials is reviewed in detail. This progress illuminates the tremendous potential that carbon-nanotube-based materials and composites have for producing high-performance next-generation devices for thermoelectric-energy harvesting. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Thermoelectricity: materials and applications

    International Nuclear Information System (INIS)

    Elberg, S.; Mathonnet, P.

    1975-01-01

    After a brief recall of the basic principles of thermoelectricity, the essential characteristics intervening in the different thermoelectric devices operating modes are defined. Properties of the materials the most used nowadays and performances of the apparatus that they allow to realize are indicated. Advantages and drawbacks of the principal applications in the form of electrical generators, refrigerators and heat pumps are pointed out [fr

  10. Effective thermal conductivity in thermoelectric materials

    Energy Technology Data Exchange (ETDEWEB)

    Baranowski, LL; Snyder, GJ; Toberer, ES

    2013-05-28

    Thermoelectric generators (TEGs) are solid state heat engines that generate electricity from a temperature gradient. Optimizing these devices for maximum power production can be difficult due to the many heat transport mechanisms occurring simultaneously within the TEG. In this paper, we develop a model for heat transport in thermoelectric materials in which an "effective thermal conductivity" (kappa(eff)) encompasses both the one dimensional steady-state Fourier conduction and the heat generation/consumption due to secondary thermoelectric effects. This model is especially powerful in that the value of kappa(eff) does not depend upon the operating conditions of the TEG but rather on the transport properties of the TE materials themselves. We analyze a variety of thermoelectric materials and generator designs using this concept and demonstrate that kappa(eff) predicts the heat fluxes within these devices to 5% of the exact value. (C) 2013 AIP Publishing LLC.

  11. Thermoelectric materials -- New directions and approaches. Materials Research Society symposium proceedings, Volume 478

    Energy Technology Data Exchange (ETDEWEB)

    Tritt, T M; Kanatzidis, M G; Lyon, Jr, H B; Mahan, G D [eds.

    1997-07-01

    Thermoelectric materials are utilized in a wide variety of applications related to solid-state refrigeration or small-scale power generation. Thermoelectric cooling is an environmentally friendly method of small-scale cooling in specific applications such as cooling computer chips and laser diodes. Thermoelectric materials are used in a wide range of applications from beverage coolers to power generation for deep-space probes such as the Voyager missions. Over the past thirty years, alloys based on the Bi-Te systems {l{underscore}brace}(Bi{sub 1{minus}x}Sb{sub x}){sub 2} (Te{sub 1{minus}x}Se{sub x}){sub 3}{r{underscore}brace} and Si{sub 1{minus}x}Ge{sub x} systems have been extensively studied and optimized for their use as thermoelectric materials to perform a variety of solid-state thermoelectric refrigeration and power generation tasks. Despite this extensive investigation of the traditional thermoelectric materials, there is still a substantial need and room for improvement, and thus, entirely new classes of compounds will have to be investigated. Over the past two-to-three years, research in the field of thermoelectric materials has been undergoing a rapid rebirth. The enhanced interest in better thermoelectric materials has been driven by the need for much higher performance and new temperature regimes for thermoelectric devices in many applications. The essence of a good thermoelectric is given by the determination of the material's dimensionless figure of merit, ZT = ({alpha}{sup 2}{sigma}/{lambda})T, where {alpha} is the Seebeck coefficient, {sigma} the electrical conductivity and {lambda} the total thermal conductivity. The best thermoelectric materials have a value of ZT = 1. This ZT = 1 has been an upper limit for more than 30 years, yet no theoretical or thermodynamic reason exits for why it can not be larger. The focus of the symposium is embodied in the title, Thermoelectric Materials: New Directions and Approaches. Many of the researchers in the

  12. Development of Perovskite-Type Materials for Thermoelectric Application

    Directory of Open Access Journals (Sweden)

    Tingjun Wu

    2018-06-01

    Full Text Available Oxide perovskite materials have a long history of being investigated for thermoelectric applications. Compared to the state-of-the-art tin and lead chalcogenides, these perovskite compounds have advantages of low toxicity, eco-friendliness, and high elemental abundance. However, because of low electrical conductivity and high thermal conductivity, the total thermoelectric performance of oxide perovskites is relatively poor. Variety of methods were used to enhance the TE properties of oxide perovskite materials, such as doping, inducing oxygen vacancy, embedding crystal imperfection, and so on. Recently, hybrid perovskite materials started to draw attention for thermoelectric application. Due to the low thermal conductivity and high Seebeck coefficient feature of hybrid perovskites materials, they can be promising thermoelectric materials and hold the potential for the application of wearable energy generators and cooling devices. This mini-review will build a bridge between oxide perovskites and burgeoning hybrid halide perovskites in the research of thermoelectric properties with an aim to further enhance the relevant performance of perovskite-type materials.

  13. A review of thermoelectric cooling: Materials, modeling and applications

    International Nuclear Information System (INIS)

    Zhao, Dongliang; Tan, Gang

    2014-01-01

    This study reviews the recent advances of thermoelectric materials, modeling approaches, and applications. Thermoelectric cooling systems have advantages over conventional cooling devices, including compact in size, light in weight, high reliability, no mechanical moving parts, no working fluid, being powered by direct current, and easily switching between cooling and heating modes. In this study, historical development of thermoelectric cooling has been briefly introduced first. Next, the development of thermoelectric materials has been given and the achievements in past decade have been summarized. To improve thermoelectric cooling system's performance, the modeling techniques have been described for both the thermoelement modeling and thermoelectric cooler (TEC) modeling including standard simplified energy equilibrium model, one-dimensional and three-dimensional models, and numerical compact model. Finally, the thermoelectric cooling applications have been reviewed in aspects of domestic refrigeration, electronic cooling, scientific application, and automobile air conditioning and seat temperature control, with summaries for the commercially available thermoelectric modules and thermoelectric refrigerators. It is expected that this study will be beneficial to thermoelectric cooling system design, simulation, and analysis. - Highlights: •Thermoelectric cooling has great prospects with thermoelectric material's advances. •Modeling techniques for both thermoelement and TEC have been reviewed. •Principle thermoelectric cooling applications have been reviewed and summarized

  14. Measurement and characterization techniques for thermoelectric materials

    Energy Technology Data Exchange (ETDEWEB)

    Tritt, T M

    1997-07-01

    Characterization of thermoelectric materials can pose many problems. A temperature difference can be established across these materials as an electrical current is passed due to the Peltier effect. The thermopower of these materials is quite large and thus large thermal voltages can contribute to many of the measurements necessary to investigate these materials. This paper will discuss the chracterization techniques necessary to investigate these materials and provide an overview of some of the potential systematic errors which can arise. It will also discuss some of the corrections one needs to consider. This should provide an introduction to the characterization and measurement of thermoelectric materials and provide references for a more in depth discussion of the concepts. It should also serve as an indication of the care that must be taken while working with thermoelectric materials.

  15. Portable Thermoelectric Power Generator Coupled with Phase Change Material

    Directory of Open Access Journals (Sweden)

    Lim Chong C.

    2014-07-01

    Full Text Available Solar is the intermittent source of renewable energy and all thermal solar systems having a setback on non-functioning during the night and cloudy environment. This paper presents alternative solution for power generation using thermoelectric which is the direct conversion of temperature gradient of hot side and cold side of thermoelectric material to electric voltage. Phase change material with latent heat effect would help to prolong the temperature gradient across thermoelectric material for power generation. Besides, the concept of portability will enable different power source like solar, wasted heat from air conditioner, refrigerator, stove etc, i.e. to create temperature different on thermoelectric material for power generation. Furthermore, thermoelectric will generate direct current which is used by all the gadgets like Smartphone, tablet, laptop etc. The portable concept of renewable energy will encourage the direct usage of renewable energy for portable gadgets. The working principle and design of portable thermoelectric power generator coupled with phase change material is presented in this paper.

  16. Thermoelectric materials - Compromising between high efficiency and materials abundance

    Energy Technology Data Exchange (ETDEWEB)

    Homm, G.; Klar, P.J. [I. Physikalisches Institut, Justus-Liebig-Universitaet, Heinrich-Buff-Ring 16, 35392 Giessen (Germany)

    2011-09-15

    In the context of CO{sub 2} neutral and regenerative energy production, the field of thermoelectrics has shifted more and more into the focus of scientific research in the last few years. Particularly a lot of research projects were started in the field of energy autarkic sensor technology and the so called energy harvesting, i.e. the recycling of otherwise lost energy. A potentially huge industrial branch for thermoelectric applications is the automotive industry with a main emphasis on generating electricity out of the waste heat of combustion engines with the help of thermoelectric generators or using Peltier cooling to replace conventional air conditioning in the passenger compartment. In addition, many niche applications are possible, e.g. as sensors for measuring the air pressure of tires etc. The applications of thermoelectric devices are very versatile. We analyse the potential of the state-of-the-art thermoelectric materials SiGe, PbTe, Bi{sub 2}Te{sub 3}, FeSi{sub 2} and potentially ZnO with respect to employment in four types of applications, classified by mobile vs stationary and specialized vs. mass application. The selection criteria comprise efficiency, materials availability, costs, environmental friendliness and toxicity. Based on these criteria, a decision matrix for choosing the appropriate material system for a specific application is defined. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  17. Thermoelectric Materials

    Science.gov (United States)

    Gao, Peng; Berkun, Isil; Schmidt, Robert D.; Luzenski, Matthew F.; Lu, Xu; Bordon Sarac, Patricia; Case, Eldon D.; Hogan, Timothy P.

    2014-06-01

    Mg2(Si,Sn) compounds are promising candidate low-cost, lightweight, nontoxic thermoelectric materials made from abundant elements and are suited for power generation applications in the intermediate temperature range of 600 K to 800 K. Knowledge on the transport and mechanical properties of Mg2(Si,Sn) compounds is essential to the design of Mg2(Si,Sn)-based thermoelectric devices. In this work, such materials were synthesized using the molten-salt sealing method and were powder processed, followed by pulsed electric sintering densification. A set of Mg2.08Si0.4- x Sn0.6Sb x (0 ≤ x ≤ 0.072) compounds were investigated, and a peak ZT of 1.50 was obtained at 716 K in Mg2.08Si0.364Sn0.6Sb0.036. The high ZT is attributed to a high electrical conductivity in these samples, possibly caused by a magnesium deficiency in the final product. The mechanical response of the material to stresses is a function of the elastic moduli. The temperature-dependent Young's modulus, shear modulus, bulk modulus, Poisson's ratio, acoustic wave speeds, and acoustic Debye temperature of the undoped Mg2(Si,Sn) compounds were measured using resonant ultrasound spectroscopy from 295 K to 603 K. In addition, the hardness and fracture toughness were measured at room temperature.

  18. Test System for Thermoelectric Modules and Materials

    Science.gov (United States)

    Hejtmánek, J.; Knížek, K.; Švejda, V.; Horna, P.; Sikora, M.

    2014-10-01

    We present a design for a complex measuring device that enables its user to assess the parameters of power-generating thermoelectric modules (TEMs) (or bulk thermoelectric materials) under a wide range of temperatures ( T cold = 25°C to 90°C, T hot TEM, the actual heat flow through the module, and its mechanical load, which can be varied during the measurement. Key components of our testing setup are (i) a measuring chamber where the TEM/material is compressed between thermally shielded heating blocks equipped with a mechanical loading system and water-cooled copper-based cooler, (ii) an electrical load system, (iii) a type K thermocouple array connected to a data acquisition computer, and (iv) a thermostatic water-based cooling system with electronically controlled flow rate and temperature of cooling water. Our testing setup represents a useful tool able to assess, e.g., the thermoelectric parameters of newly developed TEMs and materials or to evaluate the thermoelectric parameters of commercially available modules and materials for comparison with values declared by the manufacturer.

  19. Nanostructured layers of thermoelectric materials

    Energy Technology Data Exchange (ETDEWEB)

    Urban, Jeffrey J.; Lynch, Jared; Coates, Nelson; Forster, Jason; Sahu, Ayaskanta; Chabinyc, Michael; Russ, Boris

    2018-01-30

    This disclosure provides systems, methods, and apparatus related to thermoelectric materials. In one aspect, a method includes providing a plurality of nanostructures. The plurality of nanostructures comprise a thermoelectric material, with each nanostructure of the plurality of nanostructures having first ligands disposed on a surface of the nanostructure. The plurality of nanostructures is mixed with a solution containing second ligands and a ligand exchange process occurs in which the first ligands disposed on the plurality of nanostructures are replaced with the second ligands. The plurality of nanostructures is deposited on a substrate to form a layer. The layer is thermally annealed.

  20. Designing high-Performance layered thermoelectric materials through orbital engineering

    DEFF Research Database (Denmark)

    Zhang, Jiawei; Song, Lirong; Madsen, Georg K. H.

    2016-01-01

    Thermoelectric technology, which possesses potential application in recycling industrial waste heat as energy, calls for novel high-performance materials. The systematic exploration of novel thermoelectric materials with excellent electronic transport properties is severely hindered by limited...... insight into the underlying bonding orbitals of atomic structures. Here we propose a simple yet successful strategy to discover and design high-performance layered thermoelectric materials through minimizing the crystal field splitting energy of orbitals to realize high orbital degeneracy. The approach...... naturally leads to design maps for optimizing the thermoelectric power factor through forming solid solutions and biaxial strain. Using this approach, we predict a series of potential thermoelectric candidates from layered CaAl2Si2-type Zintl compounds. Several of them contain nontoxic, low-cost and earth...

  1. Thermoelectric nanomaterials materials design and applications

    CERN Document Server

    Koumoto, Kunihito

    2014-01-01

    Presently, there is an intense race throughout the world to develop good enough thermoelectric materials which can be used in wide scale applications. This book focuses comprehensively on very recent up-to-date breakthroughs in thermoelectrics utilizing nanomaterials and methods based in nanoscience. Importantly, it provides the readers with methodology and concepts utilizing atomic scale and nanoscale materials design (such as superlattice structuring, atomic network structuring and properties control, electron correlation design, low dimensionality, nanostructuring, etc.). Furthermore, also

  2. On the Phase Separation in n-Type Thermoelectric Half-Heusler Materials

    Directory of Open Access Journals (Sweden)

    Michael Schwall

    2018-04-01

    Full Text Available Half-Heusler compounds have been in focus as potential materials for thermoelectric energy conversion in the mid-temperature range, e.g., as in automotive or industrial waste heat recovery, for more than ten years now. Because of their mechanical and thermal stability, these compounds are advantageous for common thermoelectric materials such as Bi 2 Te 3 , SiGe, clathrates or filled skutterudites. A further advantage lies in the tunability of Heusler compounds, allowing one to avoid expensive and toxic elements. Half-Heusler compounds usually exhibit a high electrical conductivity σ , resulting in high power factors. The main drawback of half-Heusler compounds is their high lattice thermal conductivity. Here, we present a detailed study of the phase separation in an n-type Heusler materials system, showing that the Ti x Zr y Hf z NiSn system is not a solid solution. We also show that this phase separation is key to the thermoelectric high efficiency of n-type Heusler materials. These results strongly underline the importance of phase separation as a powerful tool for designing highly efficient materials for thermoelectric applications that fulfill the industrial demands of a thermoelectric converter.

  3. Portable Thermoelectric Power Generator Coupled with Phase Change Material

    OpenAIRE

    Lim Chong C.; Al-Kayiem Hussain H.; Sing Chin Y.

    2014-01-01

    Solar is the intermittent source of renewable energy and all thermal solar systems having a setback on non-functioning during the night and cloudy environment. This paper presents alternative solution for power generation using thermoelectric which is the direct conversion of temperature gradient of hot side and cold side of thermoelectric material to electric voltage. Phase change material with latent heat effect would help to prolong the temperature gradient across thermoelectric material f...

  4. Knudsen pump driven by a thermoelectric material

    International Nuclear Information System (INIS)

    Pharas, Kunal; McNamara, Shamus

    2010-01-01

    The first use of a thermoelectric material in the bidirectional operation of a gas pump using thermal transpiration has been demonstrated. The thermoelectric material maintains a higher temperature difference which favors thermal transpiration and thus increases the efficiency of gas pumping. Since the hot and cold sides of the thermoelectric material are reversible, the direction of the pump may be changed by reversing the electrical current direction. Two different pump designs are presented that illustrate some of the design tradeoffs. The pumps are characterized by measuring the pressure difference that may be generated and by measuring the flow rate in the forward and reverse directions. For a pump composed of a porous material with a pore size of 100 nm, a maximum flow rate of 0.74 cm 3 min −1 and a maximum pressure of 1.69 kPa are achieved

  5. Nanoscale thermoelectric materials

    International Nuclear Information System (INIS)

    Failamani, F.

    2015-01-01

    Thermoelectric (TE) materials directly convert thermal energy to electrical energy when subjected to a temperature gradient, whereas if electricity is applied to thermoelectric materials, a temperature gradient is formed. The performance of thermoelectric materials is characterized by a dimensionless figure of merit (ZT = S2T/ρλ), which consists of three parameters, Seebeck coefficient (S), electrical resistivity (ρ) and thermal conductivity (λ). To achieve good performance of thermoelectric power generation and cooling, ZT's of thermoelectric materials must be as high as possible, preferably above unity. This thesis comprises three main parts, which are distributed into six chapters: (i) nanostructuring to improve TE performance of trivalent rare earth-filled skutterudites (chapter 1 and 2), (ii) interactions of skutterudite thermolectrics with group V metals as potential electrode or diffusion barrier for TE devices (chapter 3 and 4), and (iii) search for new materials for TE application (chapter 5 and 6). Addition of secondary phases, especially nano sized phases can cause additional reduction of the thermal conductivity of a filled skutterudite which improves the figure of merit (ZT) of thermoelectric materials. In chapter 1 we investigated the effect of various types of secondary phases (silicides, borides, etc.) on the TE properties of trivalent rare earth filled Sb-based skutterudites as commercially potential TE materials. In this context the possibilty to introduce borides as nano-particles (via ball-milling in terms of a skutterudite/boride composite) is also elucidated in chapter 2. As a preliminary study, crystal structure of novel high temperature FeB-type phases found in the ternary Ta-{Ti,Zr,Hf,}-B systems were investigated. In case of Ti and Hf this phase is the high temperature stabilization of binary group IV metal monoborides, whereas single crystal study of (Ta,Zr)B proves that it is a true ternary phase as no stable monoboride exist in the

  6. Thermoelectric materials and devices made therewith

    International Nuclear Information System (INIS)

    Moore, D.E.

    1985-01-01

    The disclosed invention includes improved devices and materials for thermoelectric conversion, particularly for operation at temperatures of 300 0 C. and below. Disordered p-type semiconductor elements incorporate compound adjuvants of silver and lead to achieve enhanced ''figure of merit'' values and corresponding increased efficiencies of thermoelectric conversion. Similar results are obtained with disordered n-type elements by employing lowered selenium contents, preferably in combination with cuprous bromide. Improved conversion devices include powder pressed elements from one or both of these materials

  7. The effect of doping on thermoelectric performance of p-type SnSe: Promising thermoelectric material

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Niraj Kumar; Bathula, Sivaiah; Gahtori, Bhasker [CSIR-Network of Institutes for Solar Energy, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Road, New Delhi 110012 (India); Tyagi, Kriti [CSIR-Network of Institutes for Solar Energy, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Road, New Delhi 110012 (India); Acdemy of Scientific and Innovative Research (AcSIR), CSIR-National Physical Laboratory (NPL) Campus, New Delhi (India); Haranath, D. [CSIR-Network of Institutes for Solar Energy, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Road, New Delhi 110012 (India); Dhar, Ajay, E-mail: adhar@nplindia.org [CSIR-Network of Institutes for Solar Energy, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Road, New Delhi 110012 (India)

    2016-05-25

    Tin selenide (SnSe) based thermoelectric materials are being explored for making inexpensive and efficient thermoelectric devices with improved thermoelectric efficiency. As both Sn and Se are earth abundant and relatively inexpensive and these alloys do not involve toxic materials, such as lead and expensive tellurium. Hence, in the present study, we have synthesized SnSe doped with 2 at% of aluminium (Al), lead (Pb), indium (In) and copper (Cu) individually, which is not reported in literature. Out of these, Cu doped SnSe resulted in enhancement of figure-of-merit (zT) of ∼0.7 ± 0.02 at 773 K, synthesized employing conventional fusion method followed by spark plasma sintering. This enhancement in zT is ∼16% over the existing state-of-the-art value for p-type SnSe alloy doped with expensive Ag. This enhancement in ZT is primarily due to the presence of Cu{sub 2}Se second phase associated with intrinsic nanostructure formation of SnSe. This enhancement has been corroborated with the microstructural characterization using field emission scanning electron microscopy and X-ray diffraction studies. Also, Cu doped SnSe exhibited a higher value of carrier concentration in comparison to other samples doped with Al, Pb and In. Further, the compatibility factor of Cu doped SnSe alloys exhibited value of 1.62 V{sup −1} at 773 K and it is suitable to segment with most of the novel TE materials for obtaining the higher thermoelectric efficiencies. - Highlights: • Tin selenide (SnSe) doped with non-toxic and inexpensive dopants. • Synthesized highly dense SnSe employing Spark plasma sintering. • Enhanced thermoelectric compatibility factor of SnSe. • Enhanced thermoelectric performance of SnSe doped with Copper.

  8. Advanced thermoelectric materials and systems for automotive applications in the next millennium

    Energy Technology Data Exchange (ETDEWEB)

    Morelli, D T

    1997-07-01

    A combination of environmental, economic, and technological drivers has led to a reassessment of the potential for using thermoelectric devices in several automotive applications. In order for this technology to achieve its ultimate potential, new materials with enhanced thermoelectric properties are required. Experimental results on the fundamental physical properties of some new thermoelectric materials, including filled skutterudites and 1-1-1 intermetallic semiconductors, are presented.

  9. Half-Heusler Alloys as Promising Thermoelectric Materials

    Science.gov (United States)

    Page, Alexander A.

    This thesis describes Ph.D. research on the half-Heusler class of thermoelectric materials. Half-Heusler alloys are a versatile class of materials that have been studied for use in photovoltaics, phase change memory, and thermoelectric power generation. With respect to thermoelectric power generation, new approaches were recently developed in order to improve the thermoelectric figure of merit, ZT, of half-Heusler alloys. Two of the strategies discussed in this work are adding excess Ni within MNiSn (M = Ti, Zr, or Hf) compounds to form full-Heusler nanostructures and using isoelectronic substitution of Ti, Zr, and Hf in MNiSn compounds to create microscale grain boundaries. This work uses computational simulations based on density functional theory, combined with the cluster expansion method, to predict the stable phases of pseudo-binary and pseudo-ternary composition systems. Statistical mechanics methods were used to calculate temperature-composition phase diagrams that relate the equilibrium phases. It is shown that full-Heusler nanostructures are predicted to remain stable even at high temperatures, and the microscale grain boundaries observed in (Ti,Zr,Hf)NiSn materials are found to be thermodynamically unstable at equilibrium. A new strategy of combining MNiSn materials with ZrNiPb has also recently emerged, and theoretical and experimental work show that a solid solution of the two materials is stable.

  10. Pathways for acceleration of development and commercialization of novel thermoelectric materials

    Energy Technology Data Exchange (ETDEWEB)

    Jovovic, Vladimir; Heian, Ellen M.; Harris, Fred R.; Sootsman, Joseph; Kossakovski, Dmitri [ZT Plus, Azusa, CA (United States)

    2011-07-01

    Efficient and robust thermoelectric (TE) materials are the cornerstone of any future TE generator system implementation. Today, efforts at commercialization of TE materials often lack the rigor and speed necessary for market readiness of any new material. Here we present the requirements for optimizing a thermoelectric material through a defined development process. We discuss the optimization process, tools that assist in rapid evaluation of thermoelectric performance, and the reproducibility of samples when these methods are employed. The results from our case study demonstrate the feasibility of this approach to prepare reproducible commercial quantities of advanced thermoelectric materials. (orig.)

  11. Review—Organic Materials for Thermoelectric Energy Generation

    KAUST Repository

    Cowen, Lewis M.; Atoyo, Jonathan; Carnie, Matthew J.; Baran, Derya; Schroeder, Bob C.

    2017-01-01

    Organic semiconductor materials have been promising alternatives to their inorganic counterparts in several electronic applications such as solar cells, light emitting diodes, field effect transistors as well as thermoelectric generators. Their low cost, light weight and flexibility make them appealing in future applications such as foldable electronics and wearable circuits using printing techniques. In this report, we present a mini-review on the organic materials that have been used for thermoelectric energy generation.

  12. Review—Organic Materials for Thermoelectric Energy Generation

    KAUST Repository

    Cowen, Lewis M.

    2017-01-29

    Organic semiconductor materials have been promising alternatives to their inorganic counterparts in several electronic applications such as solar cells, light emitting diodes, field effect transistors as well as thermoelectric generators. Their low cost, light weight and flexibility make them appealing in future applications such as foldable electronics and wearable circuits using printing techniques. In this report, we present a mini-review on the organic materials that have been used for thermoelectric energy generation.

  13. Yb14MnSb11 as a High-Efficiency Thermoelectric Material

    Science.gov (United States)

    Snyder, G. Jeffrey; Gascoin, Franck; Brown, Shawna; Kauzlarich, Susan

    2009-01-01

    Yb14MnSb11 has been found to be wellsuited for use as a p-type thermoelectric material in applications that involve hotside temperatures in the approximate range of 1,200 to 1,300 K. The figure of merit that characterizes the thermal-to-electric power-conversion efficiency is greater for this material than for SiGe, which, until now, has been regarded as the state-of-the art high-temperature ptype thermoelectric material. Moreover, relative to SiGe, Yb14MnSb11 is better suited to incorporation into a segmented thermoelectric leg that includes the moderate-temperature p-type thermoelectric material CeFe4Sb12 and possibly other, lower-temperature p-type thermoelectric materials. Interest in Yb14MnSb11 as a candidate high-temperature thermoelectric material was prompted in part by its unique electronic properties and complex crystalline structure, which place it in a class somewhere between (1) a class of semiconducting valence compounds known in the art as Zintl compounds and (2) the class of intermetallic compounds. From the perspective of chemistry, this classification of Yb14MnSb11 provides a first indication of a potentially rich library of compounds, the thermoelectric properties of which can be easily optimized. The concepts of the thermoelectric figure of merit and the thermoelectric compatibility factor are discussed in Compatibility of Segments of Thermo - electric Generators (NPO-30798), which appears on page 55. The traditional thermoelectric figure of merit, Z, is defined by the equation Z = alpha sup 2/rho K, where alpha is the Seebeck coefficient, rho is the electrical resistivity, and k is the thermal conductivity.

  14. Nano-Micro Materials Enabled Thermoelectricity From Window Glasses

    KAUST Repository

    Inayat, Salman Bin

    2012-01-01

    of individual glass strips to form the thickness depth of the glass on subsequent curing of the strips, and c) embedding nano-manufactured thermoelectric pillars, have been implemented for innovative integration of thermoelectric materials into window glasses

  15. Advances in thermoelectric materials research: Looking back and moving forward.

    Science.gov (United States)

    He, Jian; Tritt, Terry M

    2017-09-29

    High-performance thermoelectric materials lie at the heart of thermoelectrics, the simplest technology applicable to direct thermal-to-electrical energy conversion. In its recent 60-year history, the field of thermoelectric materials research has stalled several times, but each time it was rejuvenated by new paradigms. This article reviews several potentially paradigm-changing mechanisms enabled by defects, size effects, critical phenomena, anharmonicity, and the spin degree of freedom. These mechanisms decouple the otherwise adversely interdependent physical quantities toward higher material performance. We also briefly discuss a number of promising materials, advanced material synthesis and preparation techniques, and new opportunities. The renewable energy landscape will be reshaped if the current trend in thermoelectric materials research is sustained into the foreseeable future. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  16. High performance p-type half-Heusler thermoelectric materials

    Science.gov (United States)

    Yu, Junjie; Xia, Kaiyang; Zhao, Xinbing; Zhu, Tiejun

    2018-03-01

    Half-Heusler compounds, which possess robust mechanical strength, good high temperature thermal stability and multifaceted physical properties, have been verified as a class of promising thermoelectric materials. During the last two decades, great progress has been made in half-Heusler thermoelectrics. In this review, we summarize some representative work of p-type half-Heusler materials, the thermoelectric performance of which has been remarkably enhanced in recent years. We introduce the features of the crystal and electronic structures of half-Heusler compounds, and successful strategies for optimizing electrical and thermal transport in the p-type RFeSb (R  =  V, Nb, Ta) and MCoSb (M  =  Ti, Zr, Hf) based systems, including band engineering, the formation of solid solutions and hierarchical phonon scattering. The outlook for future research directions of half-Heusler thermoelectrics is also presented.

  17. Advanced Thermoelectric Materials for Efficient Waste Heat Recovery in Process Industries

    Energy Technology Data Exchange (ETDEWEB)

    Adam Polcyn; Moe Khaleel

    2009-01-06

    The overall objective of the project was to integrate advanced thermoelectric materials into a power generation device that could convert waste heat from an industrial process to electricity with an efficiency approaching 20%. Advanced thermoelectric materials were developed with figure-of-merit ZT of 1.5 at 275 degrees C. These materials were not successfully integrated into a power generation device. However, waste heat recovery was demonstrated from an industrial process (the combustion exhaust gas stream of an oxyfuel-fired flat glass melting furnace) using a commercially available (5% efficiency) thermoelectric generator coupled to a heat pipe. It was concluded that significant improvements both in thermoelectric material figure-of-merit and in cost-effective methods for capturing heat would be required to make thermoelectric waste heat recovery viable for widespread industrial application.

  18. From phase-change materials to thermoelectrics?

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, Matthias N.; Rosenthal, Tobias; Oeckler, Oliver [Dept. of Chemistry, Ludwig Maximilian Univ. Munich (Germany); Stiewe, Christian [German Aerospace Center, Cologne (Germany)

    2010-07-01

    Metastable tellurides play an important role as phase-change materials in data storage media and non-volatile RAM devices. The corresponding crystalline phases with very simple basic structures are not stable as bulk materials at ambient conditions, however, for a broad range of compositions they represent stable high-temperature phases. In the system Ge/Sb/Te, rocksalt-type high-temperature phases are characterized by a large number of vacancies randomly distributed over the cation position, which order as 2D vacancy layers upon cooling. Short-range order in quenched samples produces pronounced nanostructures by the formation of twin domains and finite intersecting vacancy layers. As phase-change materials are usually semimetals or small-bandgap semiconductors and efficient data storage requires low thermal conductivity, bulk materials with similar compositions and properties can be expected to exhibit promising thermoelectric characteristics. Nanostructuring by phase transitions that involve partial vacancy ordering may enhance the efficiency of such thermoelectrics. We have shown that germanium antimony tellurides with compositions close to those used as phase-change materials in rewritable Blu-Ray Discs, e.g. (GeTe){sub 12}Sb{sub 2}Te{sub 3}, exhibit thermoelectric figures of merit of up to ZT = 1.3 at 450 C if a nanodomain structure is induced by rapidly quenching the cubic high-temperature phase. Structural changes have been elucidated by X-ray diffraction and high-resolution electron microscopy. (orig.)

  19. Decoupling interrelated parameters for designing high performance thermoelectric materials.

    Science.gov (United States)

    Xiao, Chong; Li, Zhou; Li, Kun; Huang, Pengcheng; Xie, Yi

    2014-04-15

    The world's supply of fossil fuels is quickly being exhausted, and the impact of their overuse is contributing to both climate change and global political unrest. In order to help solve these escalating problems, scientists must find a way to either replace combustion engines or reduce their use. Thermoelectric materials have attracted widespread research interest because of their potential applications as clean and renewable energy sources. They are reliable, lightweight, robust, and environmentally friendly and can reversibly convert between heat and electricity. However, after decades of development, the energy conversion efficiency of thermoelectric devices has been hovering around 10%. This is far below the theoretical predictions, mainly due to the interdependence and coupling between electrical and thermal parameters, which are strongly interrelated through the electronic structure of the materials. Therefore, any strategy that balances or decouples these parameters, in addition to optimizing the materials' intrinsic electronic structure, should be critical to the development of thermoelectric technology. In this Account, we discuss our recently developed strategies to decouple thermoelectric parameters for the synergistic optimization of electrical and thermal transport. We first highlight the phase transition, which is accompanied by an abrupt change of electrical transport, such as with a metal-insulator and semiconductor-superionic conductor transition. This should be a universal and effective strategy to optimize the thermoelectric performance, which takes advantage of modulated electronic structure and critical scattering across phase transitions to decouple the power factor and thermal conductivity. We propose that solid-solution homojunction nanoplates with disordered lattices are promising thermoelectric materials to meet the "phonon glass electron crystal" approach. The formation of a solid solution, coupled with homojunctions, allows for

  20. Development in Zn4Sb-based thermoelectric materials

    DEFF Research Database (Denmark)

    Yin, Hao

    or thermopower,  the electrical conductivity, the thermal conductivity and T the absolute temperature. The best thermoelectrics are heavily doped semiconductors with high thermoelectric power factors and low thermal conductivities, known as “Phonon Glasses Electrical Crystals”. Zn4Sb3 is one such material......-section. The following part reports the effect of nano-particles on the thermoelectric properties and thermal stability of Zn4Sb3. Though TiO2 nano particles have remarkably enhanced the stability, the thermoelectric performance of all the nano-composites deteriorates. Optimization of the content of the nano...

  1. The thermoelectric process

    Energy Technology Data Exchange (ETDEWEB)

    Vining, C B

    1997-07-01

    The efficiency of thermoelectric technology today is limited by the properties of available thermoelectric materials and a wide variety of new approaches to developing better materials have recently been suggested. The key goal is to find a material with a large ZT, the dimensionless thermoelectric figure of merit. However, if an analogy is drawn between thermoelectric technology and gas-cycle engines then selecting different materials for the thermoelements is analogous to selecting a different working gas for the mechanical engine. And an attempt to improve ZT is analogous to an attempt to improve certain thermodynamic properties of the working-gas. An alternative approach is to focus on the thermoelectric process itself (rather than on ZT), which is analogous to considering alternate cycles such as Stirling vs. Brayton vs. Rankine etc., rather than merely considering alternative gases. Focusing on the process is a radically different approach compared to previous studies focusing on ZT. Aspects of the thermoelectric process and alternative approaches to efficient thermoelectric conversion are discussed.

  2. Modeling of interface roughness in thermoelectric composite materials

    International Nuclear Information System (INIS)

    Gather, F; Heiliger, C; Klar, P J

    2011-01-01

    We use a network model to calculate the influence of the mesoscopic interface structure on the thermoelectric properties of superlattice structures consisting of alternating layers of materials A and B. The thermoelectric figure of merit of such a composite material depends on the layer thickness, if interface resistances are accounted for, and can be increased by proper interface design. In general, interface roughness reduces the figure of merit, again compared to the case of ideal interfaces. However, the strength of this reduction depends strongly on the type of interface roughness. Smooth atomic surface diffusion leading to alloying of materials A and B causes the largest reduction of the figure of merit. Consequently, in real structures, it is important not only to minimize interface roughness, but also to control the type of roughness. Although the microscopic effects of interfaces are only empirically accounted for, using a network model can yield useful information about the dependence of the macroscopic transport coefficients on the mesoscopic disorder in structured thermoelectric materials.

  3. High Temperature Thermoelectric Properties of ZnO Based Materials

    DEFF Research Database (Denmark)

    Han, Li

    of the dopants and dopant concentrations, a large power factor was obtainable. The sample with the composition of Zn0.9Cd0.1Sc0.01O obtained the highest zT ∼0.3 @1173 K, ~0.24 @1073K, and a good average zT which is better than the state-of-the-art n-type thermoelectric oxide materials. Meanwhile, Sc-doped Zn......This thesis investigated the high temperature thermoelectric properties of ZnO based materials. The investigation first focused on the doping mechanisms of Al-doped ZnO, and then the influence of spark plasma sintering conditions on the thermoelectric properties of Al, Ga-dually doped Zn......O. Following that, the nanostructuring effect for Al-doped ZnO was systematically investigated using samples with different microstructure morphologies. At last, the newly developed ZnCdO materials with superior thermoelectric properties and thermal stability were introduced as promising substitutions...

  4. Scientific and Technical Challenges in Thermal Transport and Thermoelectric Materials and Devices

    KAUST Repository

    O'Dwyer, Colm

    2017-01-19

    This paper considers the state-of-the-art and open scientific and technological questions in thermoelectric materials and devices, from phonon engineering and scattering methods, to new and complex materials and their thermoelectric behavior. The paper also describes recent approaches to create structural and compositional material systems designed to enhance the thermoelectric figure of merit and power factors. We also summarize and contextualize recent advances in the use of superlattice structures and porosity or roughness to influence phonon scattering mechanisms and detail some advances in integrated thermoelectric materials for generators and coolers for thermally stable photonic devices.

  5. Scientific and Technical Challenges in Thermal Transport and Thermoelectric Materials and Devices

    KAUST Repository

    O'Dwyer, Colm; Chen, Renkun; He, Jr-Hau; Lee, Jaeho; Razeeb, Kafil M.

    2017-01-01

    This paper considers the state-of-the-art and open scientific and technological questions in thermoelectric materials and devices, from phonon engineering and scattering methods, to new and complex materials and their thermoelectric behavior. The paper also describes recent approaches to create structural and compositional material systems designed to enhance the thermoelectric figure of merit and power factors. We also summarize and contextualize recent advances in the use of superlattice structures and porosity or roughness to influence phonon scattering mechanisms and detail some advances in integrated thermoelectric materials for generators and coolers for thermally stable photonic devices.

  6. Research Progress on AgSbTe2-based Thermoelectric Materials

    Institute of Scientific and Technical Information of China (English)

    CAO Qigao; MA Guang; JIA Zhihua; ZHENG Jing; LI Jin

    2012-01-01

    Thermoelectric power generation represents a class of energy conversion technology,which has been used in power supply of aeronautic and astronautic exploring missions,now showing notable advantages to harvest the widely distributed waste heat and convert the abundant solar energy into electricity at lower cost than Si-based photovoltaic technology.Thermoelectric dimensionless figure of merit ZT plays a key role in the conversion efficiency from thermal to electrical energy.Low thermal conductivity and large Seebeck coefficient make the AgSbTe2 compound a very promising candidate for high efficiency p-type thermoelectric applications.The AgSbTe2-based thermoelectric system has been repeatedly studied as prospective thermoelectric materials.In this review,we firstly clarify some fundamental tradeoffs dictating the ZT value through the relationship ZT =S2σT/κ.We also pay special attentions to the recent advances in AgSbTe2-based thermoelectric materials.Finally,we provide an outlook of new directions in this filed.

  7. Nano-Micro Materials Enabled Thermoelectricity From Window Glasses

    KAUST Repository

    Inayat, Salman Bin

    2012-11-03

    With growing world population and decreasing fossil fuel reserves we need to explore and utilize variety of renewable and clean energy sources to meet the imminent challenge of energy crisis. Solar energy is considered as the leading promising alternate energy source with the pertinent challenge of off sunshine period and uneven worldwide distribution of usable sun light. Although thermoelectricity is considered as a reasonable energy harvester from wasted heat, its mass scale usage is yet to be developed. By transforming window glasses into generators of thermoelectricity, this doctoral work explores engineering aspects of using the temperature gradient between the hot outdoor heated by the sun and the relatively cold indoor of a building for mass scale energy generation. In order to utilize the two counter temperature environments simultaneously, variety of techniques, including: a) insertion of basic metals like copper and nickel wire, b) sputtering of thermoelectric films on side walls of individual glass strips to form the thickness depth of the glass on subsequent curing of the strips, and c) embedding nano-manufactured thermoelectric pillars, have been implemented for innovative integration of thermoelectric materials into window glasses. The practical demonstration of thermoelectric windows has been validated using a finite element model to predict the behavior of thermoelectric window under variety of varying conditions. MEMS based characterization platform has been fabricated for thermoelectric characterization of thin films employing van der Pauw and four probe modules. Enhancement of thermoelectric properties of the nano- manufactured pillars due to nano-structuring, achieved through mechanical alloying of micro-sized thermoelectric powders, has been explored. Modulation of thermoelectric properties of the nano-structured thermoelectric pillars by addition of sulfur to nano-powder matrix has also been investigated in detail. Using the best possible p

  8. High Performance Bulk Thermoelectric Materials

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Zhifeng [Boston College, Chestnut Hill, MA (United States)

    2013-03-31

    Over 13 plus years, we have carried out research on electron pairing symmetry of superconductors, growth and their field emission property studies on carbon nanotubes and semiconducting nanowires, high performance thermoelectric materials and other interesting materials. As a result of the research, we have published 104 papers, have educated six undergraduate students, twenty graduate students, nine postdocs, nine visitors, and one technician.

  9. Efficient technique for computational design of thermoelectric materials

    Science.gov (United States)

    Núñez-Valdez, Maribel; Allahyari, Zahed; Fan, Tao; Oganov, Artem R.

    2018-01-01

    Efficient thermoelectric materials are highly desirable, and the quest for finding them has intensified as they could be promising alternatives to fossil energy sources. Here we present a general first-principles approach to predict, in multicomponent systems, efficient thermoelectric compounds. The method combines a robust evolutionary algorithm, a Pareto multiobjective optimization, density functional theory and a Boltzmann semi-classical calculation of thermoelectric efficiency. To test the performance and reliability of our overall framework, we use the well-known system Bi2Te3-Sb2Te3.

  10. Tools to Study Interfaces for Superconducting, Thermoelectric, and Magnetic Materials at the University of Houston

    Science.gov (United States)

    2016-09-01

    AFRL-AFOSR-VA-TR-2016-0303 Tools to Study Interfaces for Superconducting ,Thermoelectric, and Magnetic Materials Paul C. W. Chu UNIVERSITY OF HOUSTON...8/28/2014 - 8/27/2016 Title: Tools to Study Interfaces for Superconducting , Thermoelectric, and Magnetic Materials at the University of Houston...effort. Tools to Study Interfaces for Superconducting , Thermoelectric, and Magnetic Materials at the University of Houston Grant/Contract Number AFOSR

  11. NATO Advanced Research Workshop on New Materials for Thermoelectric Applications

    CERN Document Server

    Hewson, Alex

    2013-01-01

    Thermoelectric devices could play an important role in making efficient use of our energy resources but their efficiency would need to be increased for their wide scale application. There is a multidisciplinary search for materials with an enhanced thermoelectric responses for use in such devices. This volume covers the latest ideas and developments in this research field, covering topics ranging from the fabrication and characterization of new materials, particularly those with strong electron correlation, use of nanostructured, layered materials and composites, through to theoretical work to gain a deeper understanding of thermoelectric behavior. It should be a useful guide and stimulus to all working in this very topical field.

  12. Material parameters for thermoelectric performance

    Indian Academy of Sciences (India)

    The thermoelectric performance of a thermoelement is ideally defined in terms of the so-called figure-of-merit = 2 / , where , and refer respectively to the Seebeck coefficient, electrical conductivity and thermal conductivity of the thermoelement material. However, there are other parameters which are fairly good ...

  13. Mechanical Response of Thermoelectric Materials

    Energy Technology Data Exchange (ETDEWEB)

    Wereszczak, Andrew A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Case, Eldon D. [Michigan State Univ., East Lansing, MI (United States)

    2015-05-01

    A sufficient mechanical response of thermoelectric materials (TEMats) to structural loadings is a prerequisite to the exploitation of any candidate TEMat's thermoelectric efficiency. If a TEMat is mechanically damaged or cracks from service-induced stresses, then its thermal and electrical functions can be compromised or even cease. Semiconductor TEMats tend to be quite brittle and have a high coefficient of thermal expansion; therefore, they can be quite susceptible to mechanical failure when subjected to operational thermal gradients. Because of this, sufficient mechanical response (vis-a-vis, mechanical properties) of any candidate TEMat must be achieved and sustained in the context of the service-induced stress state to which it is subjected. This report provides an overview of the mechanical responses of state-of-the-art TEMats; discusses the relevant properties that are associated with those responses and their measurement; and describes important, nonequilibrium phenomena that further complicate their use in thermoelectric devices. For reference purposes, the report also includes several appendixes that list published data on elastic properties and strengths of a variety of TEMats.

  14. Study for material analogs of FeSb2: Material design for thermoelectric materials

    Science.gov (United States)

    Kang, Chang-Jong; Kotliar, Gabriel

    2018-03-01

    Using the ab initio evolutionary algorithm (implemented in uspex) and electronic structure calculations we investigate the properties of a new thermoelectric material FeSbAs, which is a material analog of the enigmatic thermoelectric FeSb2. We utilize the density functional theory and the Gutzwiller method to check the energetics. We find that FeSbAs can be made thermodynamically stable above ˜30 GPa. We investigate the electronic structure and thermoelectric properties of FeSbAs based on the density functional theory and compare with those of FeSb2. Above 50 K, FeSbAs has higher Seebeck coefficients than FeSb2. Upon doping, the figure of merit becomes larger for FeSbAs than for FeSb2. Another material analog FeSbP, was also investigated, and found thermodynamically unstable even at very high pressure. Regarding FeSb2 as a member of a family of compounds (FeSb2, FeSbAs, and FeSbP) we elucidate what are the chemical handles that control the gaps in this series. We also investigate solubility (As or P for Sb in FeSb2) we found As to be more soluble. Finally, we study a two-band model for thermoelectric properties and find that the temperature dependent chemical potential and the presence of the ionized impurities are important to explain the extremum in the Seebeck coefficient exhibited in experiments for FeSb2.

  15. Strategies for discovery and optimization of thermoelectric materials: Role of real objects and local fields

    Science.gov (United States)

    Zhu, Hao; Xiao, Chong

    2018-06-01

    Thermoelectric materials provide a renewable and eco-friendly solution to mitigate energy shortages and to reduce environmental pollution via direct heat-to-electricity conversion. Discovery of the novel thermoelectric materials and optimization of the state-of-the-art material systems lie at the core of the thermoelectric society, the basic concept behind these being comprehension and manipulation of the physical principles and transport properties regarding thermoelectric materials. In this mini-review, certain examples for designing high-performance bulk thermoelectric materials are presented from the perspectives of both real objects and local fields. The highlights of this topic involve the Rashba effect, Peierls distortion, local magnetic field, and local stress field, which cover several aspects in the field of thermoelectric research. We conclude with an overview of future developments in thermoelectricity.

  16. CuAlTe{sub 2}: A promising bulk thermoelectric material

    Energy Technology Data Exchange (ETDEWEB)

    Gudelli, Vijay Kumar [Department of Physics, Indian Institute of Technology Hyderabad, Ordnance Factory Estate, Yeddumailaram 502 205, Telangana (India); Kanchana, V., E-mail: kanchana@iith.ac.in [Department of Physics, Indian Institute of Technology Hyderabad, Ordnance Factory Estate, Yeddumailaram 502 205, Telangana (India); Vaitheeswaran, G. [Advanced Centre of Research in High Energy Materials (ACRHEM), University of Hyderabad, Prof. C. R. Rao Road, Gachibowli, Hyderabad 500 046, Telangana (India)

    2015-11-05

    Transport properties of Cu-based chalcopyrite materials are presented using the full potential linear augmented plane wave method and Boltzmann Semi-classical theory. All the studied compounds appear to be direct band gap semiconductors evaluated based on the Tran-Blaha modified Becke-Johnson potential. The heavy and light band combination found near the valence band maximum (VBM) drive these materials to possess good thermoelectric properties. Among the studied compounds, CuAlTe{sub 2} is found to be more promising, in comparison with CuGaTe{sub 2}, which is reported to be an efficient thermoelectric material with appreciable figure of merit. Another interesting fact about CuAlTe{sub 2} is the comparable thermoelectric properties possessed by both n- type and p-type carriers, which might attract good device applications and are explained in detail using the electronic structure calculations. - Highlights: • Band structure calculation of Cu(Al,Ga)Ch{sub 2} compounds with the TB-mBJ functional. • Mixed heavy-light bands near Fermi level might favour good thermoelectric properties. • Among the investigated compounds CuAlTe{sub 2} appears to be more promising. • Thermoelectric properties of CuAlTe{sub 2} are almost comparable with CuGaTe{sub 2}. • Both n,p-type thermoelectric properties of CuAlTe{sub 2} can attract device applications.

  17. Overview of industry interest in new thermoelectric materials

    Energy Technology Data Exchange (ETDEWEB)

    Lyon, Jr, H B

    1997-07-01

    The technology base for air conditioning, refrigeration, component cooling below ambient temperatures and power generation will be required to meet several new challenges. The main lines of these challenges will be presented in a way which relates them to the several new thermoelectric materials and materials engineering options being pursued by the research community. The potential benefits of thermoelectric devices are only partially met by enhancing the figure of merit ZT, the nature of the design challenge and the resulting systems approach are presented. The research and the industry are entering into a new era.

  18. Express method for contactless measurement of parameters of thermoelectric materials

    Directory of Open Access Journals (Sweden)

    Ashcheulov A. A.

    2015-08-01

    Full Text Available The paper presents an original method for contactless express measurement of parameters of thermoelectric materials. The presence of a combination of AC and DC magnetic fields in the gap of the oscillating circuit, where the monitored sample of the thermoelectric material is located, leads — due to Ampere force — to delamination of geometric regions of the occurrence of half-cycles of Foucault current. This in turn causes the appearance of additional heat losses in the oscillating circuit caused by Peltier effect. Computer modeling of these processes with the use of the software package ComsolFenlab 3.3 allowed determining the nature and magnitude of the electric currents in oscillating circuit, the range of operating frequencies, and the ratio of amplitudes of the variable and fixed components of the magnetic field. These components eventually cause a certain temperature difference along the controlled sample, which difference is proportional to the thermoelectric figure of merit Z of the material. The basic expressions are obtained for determining the value of the Seebeck coefficient a, thermal conductivity ?, electrical conductivity ? and thermoelectric figure of merit Z. A description is given to the design of the device for contactless express measurement of parameters of thermoelectric materials based on Bi—Te—Se—Sb solid solutions. Its distinctive feature is the ability to determine the symmetric and asymmetric components of the electric conductivity of the material values. The actual error in parameter measurement in this case is 2%.

  19. A Review on the Fabrication of Polymer-Based Thermoelectric Materials and Fabrication Methods

    Science.gov (United States)

    Kamarudin, Muhammad Akmal; Sahamir, Shahrir Razey; Datta, Robi Shankar; Long, Bui Duc; Mohd Sabri, Mohd Faizul; Mohd Said, Suhana

    2013-01-01

    Thermoelectricity, by converting heat energy directly into useable electricity, offers a promising technology to convert heat from solar energy and to recover waste heat from industrial sectors and automobile exhausts. In recent years, most of the efforts have been done on improving the thermoelectric efficiency using different approaches, that is, nanostructuring, doping, molecular rattling, and nanocomposite formation. The applications of thermoelectric polymers at low temperatures, especially conducting polymers, have shown various advantages such as easy and low cost of fabrication, light weight, and flexibility. In this review, we will focus on exploring new types of polymers and the effects of different structures, concentrations, and molecular weight on thermoelectric properties. Various strategies to improve the performance of thermoelectric materials will be discussed. In addition, a discussion on the fabrication of thermoelectric devices, especially suited to polymers, will also be given. Finally, we provide the challenge and the future of thermoelectric polymers, especially thermoelectric hybrid model. PMID:24324378

  20. Investigation of Nanophase Materials for Thermoelectric Applications

    National Research Council Canada - National Science Library

    Stokes, Kevin

    2004-01-01

    .... We have also made contributions to new, pressure-dependent thermoelectric transport measurement techniques and chemical techniques for creating ordered nanoparticle assemblies consisting of two different nanoparticle materials.

  1. Thinking Like a Chemist: Intuition in Thermoelectric Materials.

    Science.gov (United States)

    Zeier, Wolfgang G; Zevalkink, Alex; Gibbs, Zachary M; Hautier, Geoffroy; Kanatzidis, Mercouri G; Snyder, G Jeffrey

    2016-06-06

    The coupled transport properties required to create an efficient thermoelectric material necessitates a thorough understanding of the relationship between the chemistry and physics in a solid. We approach thermoelectric material design using the chemical intuition provided by molecular orbital diagrams, tight binding theory, and a classic understanding of bond strength. Concepts such as electronegativity, band width, orbital overlap, bond energy, and bond length are used to explain trends in electronic properties such as the magnitude and temperature dependence of band gap, carrier effective mass, and band degeneracy and convergence. The lattice thermal conductivity is discussed in relation to the crystal structure and bond strength, with emphasis on the importance of bond length. We provide an overview of how symmetry and bonding strength affect electron and phonon transport in solids, and how altering these properties may be used in strategies to improve thermoelectric performance. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Electronic fitness function for screening semiconductors as thermoelectric materials

    International Nuclear Information System (INIS)

    Xing, Guangzong; Sun, Jifeng; Li, Yuwei; Fan, Xiaofeng

    2017-01-01

    Here, we introduce a simple but efficient electronic fitness function (EFF) that describes the electronic aspect of the thermoelectric performance. This EFF finds materials that overcome the inverse relationship between σ and S based on the complexity of the electronic structures regardless of specific origin (e.g., isosurface corrugation, valley degeneracy, heavy-light bands mixture, valley anisotropy or reduced dimensionality). This function is well suited for application in high throughput screening. We applied this function to 75 different thermoelectric and potential thermoelectric materials including full- and half-Heuslers, binary semiconductors, and Zintl phases. We find an efficient screening using this transport function. The EFF identifies known high-performance p- and n-type Zintl phases and half-Heuslers. In addition, we find some previously unstudied phases with superior EFF.

  3. Design concepts for improved thermoelectric materials

    Energy Technology Data Exchange (ETDEWEB)

    Slack, G A

    1997-07-01

    Some new guidelines are given that should be useful in the search for thermoelectric materials that are better than those currently available. In particular, clathrate and cryptoclathrate compounds with filler atoms in their cages offer the ability to substantially lower the lattice thermal conductivity.

  4. Metallization for Yb14MnSb11-Based Thermoelectric Materials

    Science.gov (United States)

    Firdosy, Samad; Li, Billy Chun-Yip; Ravi, Vilupanur; Sakamoto, Jeffrey; Caillat, Thierry; Ewell, Richard C.; Brandon, Erik J.

    2011-01-01

    Thermoelectric materials provide a means for converting heat into electrical power using a fully solid-state device. Power-generating devices (which include individual couples as well as multicouple modules) require the use of ntype and p-type thermoelectric materials, typically comprising highly doped narrow band-gap semiconductors which are connected to a heat collector and electrodes. To achieve greater device efficiency and greater specific power will require using new thermoelectric materials, in more complex combinations. One such material is the p-type compound semiconductor Yb14MnSb11 (YMS), which has been demonstrated to have one of the highest ZT values at 1,000 C, the desired operational temperature of many space-based radioisotope thermoelectric generators (RTGs). Despite the favorable attributes of the bulk YMS material, it must ultimately be incorporated into a power-generating device using a suitable joining technology. Typically, processes such as diffusion bonding and/or brazing are used to join thermoelectric materials to the heat collector and electrodes, with the goal of providing a stable, ohmic contact with high thermal conductivity at the required operating temperature. Since YMS is an inorganic compound featuring chemical bonds with a mixture of covalent and ionic character, simple metallurgical diffusion bonding is difficult to implement. Furthermore, the Sb within YMS readily reacts with most metals to form antimonide compounds with a wide range of stoichiometries. Although choosing metals that react to form high-melting-point antimonides could be employed to form a stable reaction bond, it is difficult to limit the reactivity of Sb in YMS such that the electrode is not completely consumed at an operating temperature of 1,000 C. Previous attempts to form suitable metallization layers resulted in poor bonding, complete consumption of the metallization layer or fracture within the YMS thermoelement (or leg).

  5. WS2 as an excellent high-temperature thermoelectric material

    KAUST Repository

    Gandi, Appala; Schwingenschlö gl, Udo

    2014-01-01

    The potential of WS2 as a thermoelectric material is assessed. The electronic contribution to the thermoelectric properties is calculated within the constant relaxation time approximation from the electronic band structure, whereas the lattice contribution is evaluated using self-consistently calculated phonon lifetimes. In addition, the dependence of the lattice thermal conductivity on the mean free path of the phonons is determined.

  6. WS2 as an excellent high-temperature thermoelectric material

    KAUST Repository

    Gandi, Appala

    2014-11-25

    The potential of WS2 as a thermoelectric material is assessed. The electronic contribution to the thermoelectric properties is calculated within the constant relaxation time approximation from the electronic band structure, whereas the lattice contribution is evaluated using self-consistently calculated phonon lifetimes. In addition, the dependence of the lattice thermal conductivity on the mean free path of the phonons is determined.

  7. A MODIFIED VAN DER PAUW SETUP FOR MEASURING THE RESISTIVITY AND THERMOPOWER OF THERMOELECTRIC MATERIALS OF VARYING THICKNESSES

    KAUST Repository

    HITCHCOCK, DALE

    2013-10-01

    In the investigation of thermoelectric (TE) materials as a practical, and efficient, means of power generation/ refrigeration nearly ninety percent of the possible high-efficient binary compounds have been evaluated. But only a few proved to be useful such as Bi2Te3 alloys, PbTe and SiGe to name the most important materials. Therefore, in order to expand the research of high-efficiency TE materials new compounds and methods of efficiency optimization must be explored. There currently exist a vast number of uninvestigated ternary and quaternary materials that could be potential high-efficiency thermoelectric materials. The device and methodology discussed herein deal with rapidly measuring both the electrical resistivity and the Seebeck coefficient of thermoelectric materials, at a set temperature of T ≈ 300 K. Using nontraditional resistivity measurements and rapid, room-temperature thermopower measurements, a reliable and time-efficient means of gauging the power factor (defined below) values of newly synthesized thermoelectric materials is achievable. Furthermore, the efficacy of the van der Pauw technique for measuring the resistivity of thermoelectric materials has been verified. © World Scientific Publishing Company.

  8. A MODIFIED VAN DER PAUW SETUP FOR MEASURING THE RESISTIVITY AND THERMOPOWER OF THERMOELECTRIC MATERIALS OF VARYING THICKNESSES

    KAUST Repository

    HITCHCOCK, DALE; WALDROP, SPENCER; WILLIAMS, JARED; TRITT, TERRY M.

    2013-01-01

    In the investigation of thermoelectric (TE) materials as a practical, and efficient, means of power generation/ refrigeration nearly ninety percent of the possible high-efficient binary compounds have been evaluated. But only a few proved to be useful such as Bi2Te3 alloys, PbTe and SiGe to name the most important materials. Therefore, in order to expand the research of high-efficiency TE materials new compounds and methods of efficiency optimization must be explored. There currently exist a vast number of uninvestigated ternary and quaternary materials that could be potential high-efficiency thermoelectric materials. The device and methodology discussed herein deal with rapidly measuring both the electrical resistivity and the Seebeck coefficient of thermoelectric materials, at a set temperature of T ≈ 300 K. Using nontraditional resistivity measurements and rapid, room-temperature thermopower measurements, a reliable and time-efficient means of gauging the power factor (defined below) values of newly synthesized thermoelectric materials is achievable. Furthermore, the efficacy of the van der Pauw technique for measuring the resistivity of thermoelectric materials has been verified. © World Scientific Publishing Company.

  9. Thermoelectric generators incorporating phase-change materials for waste heat recovery from engine exhaust

    Science.gov (United States)

    Meisner, Gregory P; Yang, Jihui

    2014-02-11

    Thermoelectric devices, intended for placement in the exhaust of a hydrocarbon fuelled combustion device and particularly suited for use in the exhaust gas stream of an internal combustion engine propelling a vehicle, are described. Exhaust gas passing through the device is in thermal communication with one side of a thermoelectric module while the other side of the thermoelectric module is in thermal communication with a lower temperature environment. The heat extracted from the exhaust gasses is converted to electrical energy by the thermoelectric module. The performance of the generator is enhanced by thermally coupling the hot and cold junctions of the thermoelectric modules to phase-change materials which transform at a temperature compatible with the preferred operating temperatures of the thermoelectric modules. In a second embodiment, a plurality of thermoelectric modules, each with a preferred operating temperature and each with a uniquely-matched phase-change material may be used to compensate for the progressive lowering of the exhaust gas temperature as it traverses the length of the exhaust pipe.

  10. Nano-materials Enabled Thermoelectricity from Window Glasses

    KAUST Repository

    Inayat, Salman Bin

    2012-11-13

    With a projection of nearly doubling up the world population by 2050, we need wide variety of renewable and clean energy sources to meet the increased energy demand. Solar energy is considered as the leading promising alternate energy source with the pertinent challenge of off sunshine period and uneven worldwide distribution of usable sun light. Although thermoelectricity is considered as a reasonable renewable energy from wasted heat, its mass scale usage is yet to be developed. Here we show, large scale integration of nano-manufactured pellets of thermoelectric nano-materials, embedded into window glasses to generate thermoelectricity using the temperature difference between hot outside and cool inside. For the first time, this work offers an opportunity to potentially generate 304 watts of usable power from 9 m2 window at a 206C temperature gradient. If a natural temperature gradient exists, this can serve as a sustainable energy source for green building technology.

  11. Mechanical characterization of hydroxyapatite, thermoelectric materials and doped ceria

    Science.gov (United States)

    Fan, Xiaofeng

    For a variety of applications of brittle ceramic materials, porosity plays a critical role structurally and/or functionally, such as in engineered bone scaffolds, thermoelectric materials and in solid oxide fuel cells. The presence of porosity will affect the mechanical properties, which are essential to the design and application of porous brittle materials. In this study, the mechanical property versus microstructure relations for bioceramics, thermoelectric (TE) materials and solid oxide fuel cells were investigated. For the bioceramic material hydroxyapatite (HA), the Young's modulus was measured using resonant ultrasound spectroscopy (RUS) as a function of (i) porosity and (ii) microcracking damage state. The fracture strength was measured as a function of porosity using biaxial flexure testing, and the distribution of the fracture strength was studied by Weibull analysis. For the natural mineral tetrahedrite based solid solution thermoelectric material (Cu10Zn2As4S13 - Cu 12Sb4S13), the elastic moduli, hardness and fracture toughness were studied as a function of (i) composition and (ii) ball milling time. For ZiNiSn, a thermoelectric half-Heusler compound, the elastic modulus---porosity and hardness---porosity relations were examined. For the solid oxide fuel cell material, gadolina doped ceria (GDC), the elastic moduli including Young's modulus, shear modulus, bulk modulus and Poisson's ratio were measured by RUS as a function of porosity. The hardness was evaluated by Vickers indentation technique as a function of porosity. The results of the mechanical property versus microstructure relations obtained in this study are of great importance for the design and fabrication of reliable components with service life and a safety factor. The Weibull modulus, which is a measure of the scatter in fracture strength, is the gauge of the mechanical reliability. The elastic moduli and Poisson's ratio are needed in analytical or numerical models of the thermal and

  12. Energy harvesting using a thermoelectric material

    Science.gov (United States)

    Nersessian, Nersesse [Van Nuys, CA; Carman, Gregory P [Los Angeles, CA; Radousky, Harry B [San Leandro, CA

    2008-07-08

    A novel energy harvesting system and method utilizing a thermoelectric having a material exhibiting a large thermally induced strain (TIS) due to a phase transformation and a material exhibiting a stress induced electric field is introduced. A material that exhibits such a phase transformation exhibits a large increase in the coefficient of thermal expansion over an incremental temperature range (typically several degrees Kelvin). When such a material is arranged in a geometric configuration, such as, for a example, a laminate with a material that exhibits a stress induced electric field (e.g. a piezoelectric material) the thermally induced strain is converted to an electric field.

  13. Electrical properties and figures of merit for new chalcogenide-based thermoelectric materials

    Energy Technology Data Exchange (ETDEWEB)

    Schindler, J L; Hogan, T P; Brazis, P W; Kannewurf, C R; Chung, D Y; Kanatzidis, M G

    1997-07-01

    New Bi-based chalcogenide compounds have been prepared using the polychalcogenide flux technique for crystal growth. These materials exhibit characteristics of good thermoelectric materials. Single crystals of the compound CsBi{sub 4}Te{sub 6} have shown conductivity as high as 2440 S/cm with a p-type thermoelectric power of {approx}+110 {micro}V/K at room temperature. A second compound, {beta}-K{sub 2}Bi{sub 8}Se{sub 13} shows lower conductivity {approx}240 S/cm, but a larger n-type thermopower {approx}{minus}200 {micro}V/K. Thermal transport measurements have been performed on hot-pressed pellets of these materials and the results show comparable or lower thermal conductivities than Bi{sub 2}Te{sub 3}. This improvement may reflect the reduced lattice symmetry of the new chalcogenide thermoelectrics. The thermoelectric figure of merit for CsBi{sub 4}Te{sub 6} reaches ZT {approx} 0.32 at 260 K and for {beta}-K{sub 2}Bi{sub 8}Se{sub 13} ZT {approx} 0.32 at room temperature, indicating that these compounds are viable candidates for thermoelectric refrigeration applications.

  14. Nanocluster metal films as thermoelectric material for radioisotope mini battery unit

    International Nuclear Information System (INIS)

    Borisyuk, P.V.; Krasavin, A.V.; Tkalya, E.V.; Lebedinskii, Yu.Yu.; Vasiliev, O.S.; Yakovlev, V.P.; Kozlova, T.I.; Fetisov, V.V.

    2016-01-01

    The paper is devoted to studying the thermoelectric and structural properties of films based on metal nanoclusters (Au, Pd, Pt). The experimental results of the study of single nanoclusters’ tunneling conductance obtained with scanning tunneling spectroscopy are presented. The obtained data allowed us to evaluate the thermoelectric power of thin film consisting of densely packed individual nanoclusters. It is shown that such thin films can operate as highly efficient thermoelectric materials. A scheme of miniature thermoelectric radioisotope power source based on the thorium-228 isotope is proposed. The efficiency of the radioisotope battery using thermoelectric converters based on nanocluster metal films is shown to reach values up to 1.3%. The estimated characteristics of the device are comparable with the parameters of up-to-date radioisotope batteries based on nickel-63.

  15. The Effects of Doping and Processing on the Thermoelectric Properties of Platinum Diantimonide Based Materials for Cryogenic Peltier Cooling Applications

    Science.gov (United States)

    Waldrop, Spencer Laine

    The study of thermoelectrics is nearly two centuries old. In that time a large number of applications have been discovered for these materials which are capable of transforming thermal energy into electricity or using electrical work to create a thermal gradient. Current use of thermoelectric materials is in very niche applications with contemporary focus being upon their capability to recover waste heat. A relatively undeveloped region for thermoelectric application is focused upon Peltier cooling at low temperatures. Materials based on bismuth telluride semiconductors have been the gold standard for close to room temperature applications for over sixty years. For applications below room temperature, semiconductors based on bismuth antimony reign supreme with few other possible materials. The cause of this diculty in developing new, higher performing materials is due to the interplay of the thermoelectric properties of these materials. The Seebeck coecient, which characterizes the phenomenon of the conversion of heat to electricity, the electrical conductivity, and the thermal conductivity are all interconnected properties of a material which must be optimized to generate a high performance thermoelectric material. While for above room temperature applications many advancements have been made in the creation of highly ecient thermoelectric materials, the below room temperature regime has been stymied by ill-suited properties, low operating temperatures, and a lack of research. The focus of this work has been to investigate and optimize the thermoelectric properties of platinum diantimonide, PtSb2, a nearly zero gap semiconductor. The electronic properties of PtSb2 are very favorable for cryogenic Peltier applications, as it exhibits good conductivity and large Seebeck coecient below 200 K. It is shown that both n- and p-type doping may be applied to this compound to further improve its electronic properties. Through both solid solution formation and processing

  16. Perspective: Web-based machine learning models for real-time screening of thermoelectric materials properties

    Science.gov (United States)

    Gaultois, Michael W.; Oliynyk, Anton O.; Mar, Arthur; Sparks, Taylor D.; Mulholland, Gregory J.; Meredig, Bryce

    2016-05-01

    The experimental search for new thermoelectric materials remains largely confined to a limited set of successful chemical and structural families, such as chalcogenides, skutterudites, and Zintl phases. In principle, computational tools such as density functional theory (DFT) offer the possibility of rationally guiding experimental synthesis efforts toward very different chemistries. However, in practice, predicting thermoelectric properties from first principles remains a challenging endeavor [J. Carrete et al., Phys. Rev. X 4, 011019 (2014)], and experimental researchers generally do not directly use computation to drive their own synthesis efforts. To bridge this practical gap between experimental needs and computational tools, we report an open machine learning-based recommendation engine (http://thermoelectrics.citrination.com) for materials researchers that suggests promising new thermoelectric compositions based on pre-screening about 25 000 known materials and also evaluates the feasibility of user-designed compounds. We show this engine can identify interesting chemistries very different from known thermoelectrics. Specifically, we describe the experimental characterization of one example set of compounds derived from our engine, RE12Co5Bi (RE = Gd, Er), which exhibits surprising thermoelectric performance given its unprecedentedly high loading with metallic d and f block elements and warrants further investigation as a new thermoelectric material platform. We show that our engine predicts this family of materials to have low thermal and high electrical conductivities, but modest Seebeck coefficient, all of which are confirmed experimentally. We note that the engine also predicts materials that may simultaneously optimize all three properties entering into zT; we selected RE12Co5Bi for this study due to its interesting chemical composition and known facile synthesis.

  17. Non-invasive method of determination of thermoelectric materials figure of merit

    Directory of Open Access Journals (Sweden)

    Ashcheulov А. А.

    2009-04-01

    Full Text Available Thermoelectric effects arising in a sample placed in a measuring oscillating loop have been studied. It has been shown that asymmetric character of flowing current results in a volumetric bundle of induced Foucault currents and regions of Peltier heat release by thermoelectric sample which leads to increasing of irreversible heat losses recorded by measuring oscillating loop. The presence of this effect has caused the emergence of ingenious non-invasive method for recording of thermoelectric materials figure of merit.

  18. Nanostructured Thermoelectric Oxide Materials for Effective Power Generation from Waste Heat

    DEFF Research Database (Denmark)

    Van Nong, Ngo; Pryds, Nini

    A large amount of thermal energy that emitted from many industrial processes is available as waste heat. It is difficult to reclaim this heat due to the dispersed nature and relative smallness of its sources. Thermoelectric conversion can offer a very promising method to overcome these difficulties...... by converting heat directly into electricity. However, the requirements for this task place in the materials are not easily satisfied by the conventional thermoelectric materials. Not only they must possess a high thermoelectric performance, they should also be stable at high temperatures and be composed...... of nontoxic and low-cost elements, and must be able to be processed and shaped cheaply. Oxides are among the strongest candidate materials for this purpose, and recently they have been intensively investigated and developed [1-5]. In this report, the development progress of two state-of-the-art p-type Ca3Co4O...

  19. 3D printing of shape-conformable thermoelectric materials using all-inorganic Bi2Te3-based inks

    Science.gov (United States)

    Kim, Fredrick; Kwon, Beomjin; Eom, Youngho; Lee, Ji Eun; Park, Sangmin; Jo, Seungki; Park, Sung Hoon; Kim, Bong-Seo; Im, Hye Jin; Lee, Min Ho; Min, Tae Sik; Kim, Kyung Tae; Chae, Han Gi; King, William P.; Son, Jae Sung

    2018-04-01

    Thermoelectric energy conversion offers a unique solution for generating electricity from waste heat. However, despite recent improvements in the efficiency of thermoelectric materials, the widespread application of thermoelectric generators has been hampered by challenges in fabricating thermoelectric materials with appropriate dimensions to perfectly fit heat sources. Herein, we report an extrusion-based three-dimensional printing method to produce thermoelectric materials with geometries suitable for heat sources. All-inorganic viscoelastic inks were synthesized using Sb2Te3 chalcogenidometallate ions as inorganic binders for Bi2Te3-based particles. Three-dimensional printed materials with various geometries showed homogenous thermoelectric properties, and their dimensionless figure-of-merit values of 0.9 (p-type) and 0.6 (n-type) were comparable to the bulk values. Conformal cylindrical thermoelectric generators made of 3D-printed half rings mounted on an alumina pipe were studied both experimentally and computationally. Simulations show that the power output of the conformal, shape-optimized generator is higher than that of conventional planar generators.

  20. On the calculation of Lorenz numbers for complex thermoelectric materials

    Science.gov (United States)

    Wang, Xufeng; Askarpour, Vahid; Maassen, Jesse; Lundstrom, Mark

    2018-02-01

    A first-principles informed approach to the calculation of Lorenz numbers for complex thermoelectric materials is presented and discussed. Example calculations illustrate the importance of using accurate band structures and energy-dependent scattering times. Results obtained by assuming that the scattering rate follows the density-of-states show that in the non-degenerate limit, Lorenz numbers below the commonly assumed lower limit of 2 (kB /q ) 2 can occur. The physical cause of low Lorenz numbers is explained by the shape of the transport distribution. The numerical and physical issues that need to be addressed in order to produce accurate calculations of the Lorenz number are identified. The results of this study provide a general method that should contribute to the interpretation of measurements of total thermal conductivity and to the search for materials with low Lorenz numbers, which may provide improved thermoelectric figures of merit, z T .

  1. Functionally Graded Thermoelectric Material though One Step Band Gap and Dopant Engineering

    DEFF Research Database (Denmark)

    Jensen, Ellen Marie; Borup, Kasper Andersen; Cederkrantz, Daniel

    , and dopant concentration. Parameters relevant to the thermoelectric properties have been determined along the pulling direction. All of these properties exhibit the wanted gradient. It has thereby been shown that engineering of the electrical contributions to the thermoelectric properties of a material...

  2. Introduction to thermoelectricity

    CERN Document Server

    Goldsmid, H Julian

    2010-01-01

    Introduction to Thermoelectricity is the latest work by Professor Julian Goldsmid drawing on his 55 years experience in the field. The theory of the thermoelectric and related phenomena is presented in sufficient detail to enable researchers to understand their observations and develop improved thermoelectric materials. The methods for the selection of materials and their improvement are discussed. Thermoelectric materials for use in refrigeration and electrical generation are reviewed. Experimental techniques for the measurement of properties and for the production of thermoelements are described. Special emphasis is placed on nanotechnology which promises to yield great improvements in the efficiency of thermoelectric devices. Chapters are also devoted to transverse thermoelectric effects and thermionic energy conversion, both techniques offering the promise of important applications in the future.

  3. Spark plasma sintered bismuth telluride-based thermoelectric materials incorporating dispersed boron carbide

    Energy Technology Data Exchange (ETDEWEB)

    Williams, H.R., E-mail: hugo.williams@leicester.ac.uk [Department of Engineering, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Ambrosi, R.M. [Space Research Centre, Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Chen, K. [School of Engineering and Materials Science, Queen Mary, University of London, Mile End Road, London E1 4NS (United Kingdom); Friedman, U. [Department of Engineering, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Ning, H.; Reece, M.J. [School of Engineering and Materials Science, Queen Mary, University of London, Mile End Road, London E1 4NS (United Kingdom); Robbins, M.C.; Simpson, K. [European Thermodynamics Ltd., 8 Priory Business Park, Wistow Road, Kibworth LE8 0R (United Kingdom); Stephenson, K. [European Space Agency, ESTEC TEC-EP, Keplerlaan 1, 2201AZ Noordwijk (Netherlands)

    2015-03-25

    Highlights: • Nano-B{sub 4}C reinforced Bi{sub 0.5}Sb{sub 1.5}Te{sub 3} p-type thermoelectric produced by SPS. • Addition of B{sub 4}C up to 0.2 vol% to SPS’d material has little effect on zT. • Vickers hardness improved by 27% by adding 0.2 vol% B{sub 4}C. • Fracture toughness of SPS material: K{sub IC} = 0.80 MPa m{sup 1/2} by SEVNB. • Mechanical properties much better than commercial directionally solidified material. - Abstract: The mechanical properties of bismuth telluride based thermoelectric materials have received much less attention in the literature than their thermoelectric properties. Polycrystalline p-type Bi{sub 0.5}Sb{sub 1.5}Te{sub 3} materials were produced from powder using spark plasma sintering (SPS). The effects of nano-B{sub 4}C addition on the thermoelectric performance, Vickers hardness and fracture toughness were measured. Addition of 0.2 vol% B{sub 4}C was found to have little effect on zT but increased hardness by approximately 27% when compared to polycrystalline material without B{sub 4}C. The K{sub IC} fracture toughness of these compositions was measured as 0.80 MPa m{sup 1/2} by Single-Edge V-Notched Beam (SEVNB). The machinability of polycrystalline materials produced by SPS was significantly better than commercially available directionally solidified materials because the latter is limited by cleavage along the crystallographic plane parallel to the direction of solidification.

  4. Engineering half-Heusler thermoelectric materials using Zintl chemistry

    Science.gov (United States)

    Zeier, Wolfgang G.; Schmitt, Jennifer; Hautier, Geoffroy; Aydemir, Umut; Gibbs, Zachary M.; Felser, Claudia; Snyder, G. Jeffrey

    2016-06-01

    Half-Heusler compounds based on XNiSn and XCoSb (X = Ti, Zr or Hf) have rapidly become important thermoelectric materials for converting waste heat into electricity. In this Review, we provide an overview on the electronic properties of half-Heusler compounds in an attempt to understand their basic structural chemistry and physical properties, and to guide their further development. Half-Heusler compounds can exhibit semiconducting transport behaviour even though they are described as ‘intermetallic’ compounds. Therefore, it is most useful to consider these systems as rigid-band semiconductors within the framework of Zintl (or valence-precise) compounds. These considerations aid our understanding of their properties, such as the bandgap and low hole mobility because of interstitial Ni defects in XNiSn. Understanding the structural and bonding characteristics, including the presence of defects, will help to develop different strategies to improve and design better half-Heusler thermoelectric materials.

  5. Enhanced thermoelectric properties of metal film on bismuth telluride-based materials

    International Nuclear Information System (INIS)

    Chao, Wen Hsuan; Chen, Yi Ray; Tseng, Shih Chun; Yang, Ping Hsing; Wu, Ren Jye; Hwang, Jenn Yeu

    2014-01-01

    Diffusion barriers have a significant influence on the reliability and life time of thermoelectric modules. Although nickel is commonly used as a diffusion barrier in commercial thermoelectric modules, several studies have verified that Ni migrates to bismuth telluride-based material during high temperature cycles and causes a loss in efficacy. In this paper, the influence of metal layers coated to p-type and n-type Bi 2 Te 3 on the interface characterization and thermoelectric property is studied using a RF magnetron sputtering. The findings from this study demonstrate the structural and thermoelectric properties of p-type and n-type Bi 2 Te 3 coated with different metal layers. The crystalline phase and compositional change of the interface between the Bi 2 Te 3 materials and the metal layers were determined using an X-ray diffractometer and scanning electron microscopy with energy dispersive spectroscopy. Formation of NiTe was observed in the sample of Ni/p-type Bi 2 Te 3 based films post-annealed in an N 2 atmosphere at 200 °C. In contrast, no Co x Te y was formed in the sample of Co/p-type Bi 2 Te 3 based films post-annealed at 200 °C. For as-deposited Ni/p-type and n-type Bi 2 Te 3 based legs, the Ni slightly diffused into the Bi 2 Te 3 based legs. A similar phenomenon also occurred in the as-deposited Co/p-type and n-type Bi 2 Te 3 based legs. The Seebeck coefficients of the Co contacts on the Bi 2 Te 3 based material displayed better behavior than those of the Ni contacts on the Bi 2 Te 3 based legs. Thus Co could be a suitable diffusion barrier for bulk Bi 2 Te 3 based material. The observed effects on the thermoelectric and structural properties of metal/Bi 2 Te 3 based material are crucial for understanding the interface between the diffusion barrier and thermoelectric materials. - Highlights: • Interface characterization of metal coated to p-type and n-type Bi 2 Te 3 is studied. • We examined the phase transformation of metal/Bi 2 Te 3 based films

  6. Direct waste heat recovery via thermoelectric materials - chosen issues of the thermodynamic description

    International Nuclear Information System (INIS)

    Kolasiński, Piotr; Kolasińska, Ewa

    2016-01-01

    The effective waste heat recovery is one of the present-day challenges in the industry and power engineering. The energy systems dedicated for waste heat conversion into electricity are usually characterized by low efficiency and are complicated in the design. The possibility of waste heat recovery via thermoelectric materials may be an interesting alternative to the currently used technologies. In particular, due to their material characteristics, conducting polymers may be competitive when compared with the power machinery and equipment. These materials can be used in a wide range of the geometries e.g. the bulk products, thin films, pristine form or composites and the others. In this article, the authors present selected issues related to the mathematical and thermodynamic description of the heat transfer processes in the thermoelectric materials dedicated for the waste heat recovery. The link of these models with electrical properties of the material and a material solution based on a conducting polymer have also been presented in this paper. (paper)

  7. Thermoelectric and mechanical properties of spark plasma sintered Cu3SbSe3 and Cu3SbSe4: Promising thermoelectric materials

    Science.gov (United States)

    Tyagi, Kriti; Gahtori, Bhasker; Bathula, Sivaiah; Toutam, Vijaykumar; Sharma, Sakshi; Singh, Niraj Kumar; Dhar, Ajay

    2014-12-01

    We report the synthesis of thermoelectric compounds, Cu3SbSe3 and Cu3SbSe4, employing the conventional fusion method followed by spark plasma sintering. Their thermoelectric properties indicated that despite its higher thermal conductivity, Cu3SbSe4 exhibited a much larger value of thermoelectric figure-of-merit as compared to Cu3SbSe3, which is primarily due to its higher electrical conductivity. The thermoelectric compatibility factor of Cu3SbSe4 was found to be ˜1.2 as compared to 0.2 V-1 for Cu3SbSe3 at 550 K. The results of the mechanical properties of these two compounds indicated that their microhardness and fracture toughness values were far superior to the other competing state-of-the-art thermoelectric materials.

  8. Tuning the Transport Properties of Layered Materials for Thermoelectric Applications using First-Principles Calculations

    KAUST Repository

    Saeed, Yasir

    2014-05-11

    Thermoelectric materials can convert waste heat into electric power and thus provide a way to reduce the dependence on fossil fuels. Our aim is to model the underlying materials properties and, in particular, the transport as controlled by electrons and lattice vibrations. The goal is to develop an understanding of the thermoelectric properties of selected materials at a fundamental level. The structural, electronic, optical, and phononic properties are studied in order to tune the transport, focusing on KxRhO2, NaxRhO2, PtSb2 and Bi2Se3. The investigations are based on density functional theory as implemented in the all electron linearized augmented plane wave plus local orbitals WIEN2k and pseudo potential Quantum-ESPRESSO codes. The thermoelectric properties are derived from Boltzmann transport theory under the constant relaxation time approximation, using the BoltzTraP code. We will discuss first the changes in the electronic band structure under variation of the cation concentration in layered KxRhO2 in the 2H phase and NaxRhO2 in the 3R phase. We will also study the hydrated phase. The deformations of the RhO6 octahedra turn out to govern the thermoelectric properties, where the high Seebeck coefficient results from ”pudding mold" bands. We investigate the thermoelectric properties of electron and hole doped PtSb2, which is not a layered material but shares “pudding mold" bands. PtSb2 has a high Seebeck coefficient at room temperature, which increases significantly under As alloying by bandgap opening and reduction of the lattice thermal conductivity. Bi2Se3 (bulk and thin film) has a larger bandgap then the well-known thermoelectric material Bi2Te3, which is important at high temperature. The structural stability, electronic structure, and transport properties of one to six quintuple layers of Bi2Se3 will be discussed. We also address the effect of strain on a single quintuple layer by phonon band structures. We will analyze the electronic and transport

  9. Flexible screen printed thick film thermoelectric generator with reduced material resistivity

    International Nuclear Information System (INIS)

    Cao, Z; Koukharenko, E; Torah, R N; Tudor, J; Beeby, S P

    2014-01-01

    This work presents a flexible thick-film Bismuth Tellurium/Antimony Tellurium (BiTe/SbTe) thermoelectric generator (TEG) with reduced material resistivity fabricated by screen printing technology. Cold isostatic pressing (CIP) was introduced to lower the resistivity of the printed thermoelectric materials. The Seebeck coefficient (α) and the resistivity (ρ) of printed materials were measured as a function of applied pressure. A prototype TEG with 8 thermocouples was fabricated on flexible polyimide substrate. The dimension of a single printed element was 20 mm × 2 mm × 78.4 pm. The coiled-up prototype produced a voltage of 36.4 mV and a maximum power of 40.3 nW from a temperature gradient of 20 °C

  10. Thermoelectric properties and nanostructures of materials prepared from rice husk ash

    Energy Technology Data Exchange (ETDEWEB)

    Pukird, S.; Tipparach, U.; Kasian, P. [Ubon Ratchathani Univ., Ubon Ratchathani (Thailand). Dept. of Physics; Limsuwan, P. [King Mongkut' s Univ. of Technology Thonburi, Bangkok (Thailand). Dept. of Physics

    2009-07-01

    Thailand produces large amounts of agricultural residues such as rice husk and coconut shells. Rice husk is considered to be a potential source for solar grade silicon. Studies have shown that reasonably pure polycrystalline silicon can be prepared from rice husk white ash by a metallothermic reduction process. This paper reported on a study that investigated the thermoelectric properties of ceramic material prepared by mixing silica from rice husk ash and carbon obtained from coconut shell charcoal. The thermoelectric properties of the materials were examined along with their microstructures. The materials were made from burning rice husk ash and coconut shell at different temperatures and then doped with metal oxides. Pellets were heated at temperature of 700 degrees C for 1-3 hours. The voltage on both sides of the pellets was observed. The electromotive force was found when different temperatures were applied on both sides of the pellet specimens. The Seebeck coefficient was then calculated. The results showed that these materials can be used as thermoelectric devices. Scanning electron microscope (SEM) and energy dispersive X-rays (EDX) were used to investigate the source of materials and the products on the substrates. The images of SEM and EDX showed nanostructures of materials such as nanowires, nanorods and nanoparticles of the products and sources. 22 refs., 2 tabs., 9 figs.

  11. Thermoelectric behavior of conducting polymers: On the possibility of off-diagonal thermoelectricity

    Energy Technology Data Exchange (ETDEWEB)

    Mateeva, N; Niculescu, H; Schlenoff, J; Testardi, L

    1997-07-01

    Non-cubic materials, when structurally aligned, possess sufficient anisotropy to exhibit thermoelectric effects where the electrical and thermal currents are orthogonal (off-diagonal thermoelectricity). The authors discuss the benefits of this form of thermoelectricity for devices and describe a search for suitable properties in the air-stable conducting polymers polyaniline and polypyrrole. They find the simple and general correlation that the logarithm of the electrical conductivity scales linearly with the Seebeck coefficient on doping but with proportionality in excess of the conventional prediction for thermoelectricity. The correlation is unexpected in its universality and unfavorable for thermoelectric applications. A simple model suggests that mobile charges of both signs exist in these polymers, and this leads to reduced thermoelectric efficiency. They also briefly discuss non air-stable polyacetylene, where ambipolar transport does not appear to occur, and where properties seem more favorable for thermoelectricity.

  12. High-performance thermoelectric materials based on ternary TiO2/CNT/PANI composites.

    Science.gov (United States)

    Erden, Fuat; Li, Hui; Wang, Xizu; Wang, FuKe; He, Chaobin

    2018-04-04

    In the present work, we report the fabrication of high-performance thermoelectric materials using TiO2/CNT/PANI ternary composites. We showed that a conductivity of ∼2730 S cm-1 can be achieved for the binary CNT (70%)/PANI (30%) composite, which is the highest recorded value for the reported CNT/PANI composites. We further demonstrated that the Seebeck coefficient of CNT/PANI composites could be enhanced by incorporating TiO2 nanoparticles into the binary CNT/PANI composites, which could be attributed to lower carrier density and the energy scattering of low-energy carriers at the interfaces of TiO2/a-CNT and TiO2/PANI. The resulting TiO2/a-CNT/PANI ternary system exhibits a higher Seebeck coefficient and enhanced thermoelectric power. Further optimization of the thermoelectric power was achieved by water treatment and by tuning the processing temperature. A high thermoelectric power factor of 114.5 μW mK-2 was obtained for the ternary composite of 30% TiO2/70% (a-CNT (70%)/PANI (30%)), which is the highest reported value among the reported PANI based ternary composites. The improvement of thermoelectric performance by incorporation of TiO2 suggests a promising approach to enhance power factor of organic thermoelectric materials by judicial tuning of the carrier concentration and electrical conductivity.

  13. Compliant Interfacial Layers in Thermoelectric Devices

    Science.gov (United States)

    Firdosy, Samad A. (Inventor); Li, Billy Chun-Yip (Inventor); Ravi, Vilupanur A. (Inventor); Fleurial, Jean-Pierre (Inventor); Caillat, Thierry (Inventor); Anjunyan, Harut (Inventor)

    2017-01-01

    A thermoelectric power generation device is disclosed using one or more mechanically compliant and thermally and electrically conductive layers at the thermoelectric material interfaces to accommodate high temperature differentials and stresses induced thereby. The compliant material may be metal foam or metal graphite composite (e.g. using nickel) and is particularly beneficial in high temperature thermoelectric generators employing Zintl thermoelectric materials. The compliant material may be disposed between the thermoelectric segments of the device or between a thermoelectric segment and the hot or cold side interconnect of the device.

  14. Influence of the effectiveness of raw materials on the reliability of thermoelectric cooling devices. Part I: single-stage TEDs

    Directory of Open Access Journals (Sweden)

    Zaikov V. P.

    2015-02-01

    Full Text Available Increase of the reliability of information systems depends on the reliability improvement of their component elements, including cooling devices, providing efficiency of thermally loaded components. Thermoelectric devices based on the Peltier effect have significant advantages compared with air and liquid systems for thermal modes of the radio-electronic equipment. This happens due to the absence of moving parts, which account for the failure rate. The article presents research results on how thermoelectric efficiency modules affect the failure rate and the probability of non-failure operation in the range of working temperature of thermoelectric coolers. The authors investigate a model of relative failure rate and the probability of failure-free operation single-stage thermoelectric devices depending on the main relevant parameters: the operating current flowing through the thermocouple and resistance, temperature changes, the magnitude of the heat load and the number of elements in the module. It is shown that the increase in the thermoelectric efficiency of the primary material for a variety of thermocouple temperature changes causes the following: maximum temperature difference increases by 18%; the number of elements in the module decreases; cooling coefficient increases; failure rate reduces and the probability of non-failure operation of thermoelectric cooling device increases. Material efficiency increase by 1% allows reducing failure rate by 2,6—4,3% in maximum refrigeration capacity mode and by 4,2—5,0% in minimal failure rate mode when temperature difference changes in the range of 40—60 K. Thus, the increase in the thermoelectric efficiency of initial materials of thermocouples can significantly reduce the failure rate and increase the probability of failure of thermoelectric coolers depending on the temperature difference and the current operating mode.

  15. Development and Processing of p-type Oxide Thermoelectric Materials

    DEFF Research Database (Denmark)

    Wu, NingYu; Van Nong, Ngo

    The main aim of this research is to investigate and develop well-performing p-type thermoelectric oxide materials that are sufficiently stable at high temperatures for power generating applications involving industrial processes. Presently, the challenges facing the widespread implementation...

  16. Materials growth and characterization of thermoelectric and resistive switching devices

    Science.gov (United States)

    Norris, Kate J.

    In the 74 years since diode rectifier based radar technology helped the allied forces win WWII, semiconductors have transformed the world we live in. From our smart phones to semiconductor-based energy conversion, semiconductors touch every aspect of our lives. With this thesis I hope to expand human knowledge of semiconductor thermoelectric devices and resistive switching devices through experimentation with materials growth and subsequent materials characterization. Metal organic chemical vapor deposition (MOCVD) was the primary method of materials growth utilized in these studies. Additionally, plasma enhanced chemical vapor deposition (PECVD), atomic layer deposition (ALD),ion beam sputter deposition, reactive sputter deposition and electron-beam (e-beam) evaporation were also used in this research for device fabrication. Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), and Electron energy loss spectroscopy (EELS) were the primary characterization methods utilized for this research. Additional device and materials characterization techniques employed include: current-voltage measurements, thermoelectric measurements, x-ray diffraction (XRD), reflection absorption infra-red spectroscopy (RAIRS), atomic force microscopy (AFM), photoluminescence (PL), and raman spectroscopy. As society has become more aware of its impact on the planet and its limited resources, there has been a push toward developing technologies to sustainably produce the energy we need. Thermoelectric devices convert heat directly into electricity. Thermoelectric devices have the potential to save huge amounts of energy that we currently waste as heat, if we can make them cost-effective. Semiconducting thin films and nanowires appear to be promising avenues of research to attain this goal. Specifically, in this work we will explore the use of ErSb thin films as well as Si and InP nanowire networks for thermoelectric applications. First we will discuss the growth of

  17. Electron mean-free-path filtering in Dirac material for improved thermoelectric performance.

    Science.gov (United States)

    Liu, Te-Huan; Zhou, Jiawei; Li, Mingda; Ding, Zhiwei; Song, Qichen; Liao, Bolin; Fu, Liang; Chen, Gang

    2018-01-30

    Recent advancements in thermoelectric materials have largely benefited from various approaches, including band engineering and defect optimization, among which the nanostructuring technique presents a promising way to improve the thermoelectric figure of merit ( zT ) by means of reducing the characteristic length of the nanostructure, which relies on the belief that phonons' mean free paths (MFPs) are typically much longer than electrons'. Pushing the nanostructure sizes down to the length scale dictated by electron MFPs, however, has hitherto been overlooked as it inevitably sacrifices electrical conduction. Here we report through ab initio simulations that Dirac material can overcome this limitation. The monotonically decreasing trend of the electron MFP allows filtering of long-MFP electrons that are detrimental to the Seebeck coefficient, leading to a dramatically enhanced power factor. Using SnTe as a material platform, we uncover this MFP filtering effect as arising from its unique nonparabolic Dirac band dispersion. Room-temperature zT can be enhanced by nearly a factor of 3 if one designs nanostructures with grain sizes of ∼10 nm. Our work broadens the scope of the nanostructuring approach for improving the thermoelectric performance, especially for materials with topologically nontrivial electronic dynamics.

  18. Apparatuses And Systems For Embedded Thermoelectric Generators

    KAUST Repository

    Hussain, Muhammad M.; Inayat, Salman Bin; Smith, Casey Eben

    2013-01-01

    An apparatus and a system for embedded thermoelectric generators are disclosed. In one embodiment, the apparatus is embedded in an interface where the ambient temperatures on two sides of the interface are different. In one embodiment, the apparatus is fabricated with the interface in integrity as a unitary piece. In one embodiment, the apparatus includes a first thermoelectric material embedded through the interface. The apparatus further includes a second thermoelectric material embedded through the interface. The first thermoelectric material is electrically coupled to the second thermoelectric material. In one embodiment, the apparatus further includes an output structure coupled to the first thermoelectric material and the second thermoelectric material and configured to output a voltage.

  19. Apparatuses And Systems For Embedded Thermoelectric Generators

    KAUST Repository

    Hussain, Muhammad M.

    2013-08-08

    An apparatus and a system for embedded thermoelectric generators are disclosed. In one embodiment, the apparatus is embedded in an interface where the ambient temperatures on two sides of the interface are different. In one embodiment, the apparatus is fabricated with the interface in integrity as a unitary piece. In one embodiment, the apparatus includes a first thermoelectric material embedded through the interface. The apparatus further includes a second thermoelectric material embedded through the interface. The first thermoelectric material is electrically coupled to the second thermoelectric material. In one embodiment, the apparatus further includes an output structure coupled to the first thermoelectric material and the second thermoelectric material and configured to output a voltage.

  20. Arsenene and Antimonene: Two-Dimensional Materials with High Thermoelectric Figures of Merit

    KAUST Repository

    Sharma, S.

    2017-10-25

    We study the thermoelectric properties of As and Sb monolayers (arsenene and antimonene) using density-functional theory and the semiclassical Boltzmann transport approach. The materials show large band gaps combined with low lattice thermal conductivities. Specifically, the small phonon frequencies and group velocities of antimonene lead to an excellent thermoelectric response at room temperature. We show that n-type doping enhances the figure of merit.

  1. Simultaneous control of thermoelectric properties in p- and n-type materials by electric double-layer gating: New design for thermoelectric device

    Science.gov (United States)

    Takayanagi, Ryohei; Fujii, Takenori; Asamitsu, Atsushi

    2015-05-01

    We report a novel design of a thermoelectric device that can control the thermoelectric properties of p- and n-type materials simultaneously by electric double-layer gating. Here, p-type Cu2O and n-type ZnO were used as the positive and negative electrodes of the electric double-layer capacitor structure. When a gate voltage was applied between the two electrodes, holes and electrons accumulated on the surfaces of Cu2O and ZnO, respectively. The thermopower was measured by applying a thermal gradient along the accumulated layer on the electrodes. We demonstrate here that the accumulated layers worked as a p-n pair of the thermoelectric device.

  2. Thermoelectric and thermospintronic transport in Dirac material-based nanostructures

    Science.gov (United States)

    Chang, Po-Hao

    The growing need for power due to the rapid developments of the technologies has urged both engineers and scientists to study more sustainable types of energy. On the other hand, the improvement of our abilities although enable us, for example, to double the number of transistors in a dense integrated circuit approximately every two years (Moore's law), comes with side effect due to overheating. Taking advantage of thermoelectric effect has thus become one of the obvious solutions for the problems. But due to the poor efficiency of electricity-heat conversion, there are still challenges to be overcome in order to fully utilize the idea. In the past few years, the realization of graphene along with the discoveries of topological insulators (TI) which are both considered as Dirac material (DM) have offer alternative routs for improving the energy conversion efficiency through different approaches as well as novel quantum effects of materials themselves for investigation. The aim of this thesis is to present contributions to improving the efficiency of thermoelectric conversion as well as analyzing spin transport phenomena that occur in nano-devices. This thesis spans the areas of thermoelectric (TE) effect, spin-Seebeck effect (SSE) and the spin transport on the 3D topological insulator (TI). The different methods have been applied ranging from tight-binding (TB) approximation to density function theory (DFT) combined with non-equilibrium function (NEGF) techniques.

  3. GEO-TEP. Development of thermoelectric materials for geothermal energy conversion systems. Final report 2008

    Energy Technology Data Exchange (ETDEWEB)

    Bocher, L.; Weidenkaff, A.

    2008-07-01

    Geothermal heat can be directly converted into electricity by using thermoelectric converters. Thermoelectric conversion relies on intrinsic materials properties which have to be optimised. In this work novel environmentally friendly and stable oxide ceramics were developed to fulfil this task. Thus, manganate phases were studied regarding their potential thermoelectric properties for converting geothermal heat into electricity. Perovskite-type phases were synthesized by applying different methods: the ceramic route, and innovative synthesis routes such as the 'chimie douce' method by bulk thermal decomposition of the citrate precursor or using an USC process, and also the polyol-mediated synthesis route. The crystal structures of the manganate phases are evaluated by XRPD, NPD, and ED techniques while specific microstructures such as twinned domains are highlighted by HRTEM imaging. Besides, the thermal stability of the Mn-oxide phases in air atmosphere are controlled over a wide temperature range (T < 1300 K). The thermoelectric figure of merit ZT was enhanced from 0.021 to 0.3 in a broad temperature range for the studied phases which makes these phases the best perovskitic candidates as n-type polycrystalline thermoelectric materials operating in air at high temperatures. (author)

  4. Doping in controlling the type of conductivity in bulk and nanostructured thermoelectric materials

    International Nuclear Information System (INIS)

    Fuks, D.; Komisarchik, G.; Kaller, M.; Gelbstein, Y.

    2016-01-01

    Doping of materials for thermoelectric applications is widely used nowadays to control the type of conductivity. We report the results of ab-initio calculations aimed at developing the consistent scheme for determining the role of impurities that may change the type of conductivity in two attractive thermoelectric classes of materials. It is demonstrated that alloying of TiNiSn with Cu makes the material of n-type, and alloying with Fe leads to p-type conductivity. Similar calculations for PbTe with small amount of Na substituting for Pb leads to p-type conductivity, while Cl substituting for Te makes PbTe an n-type material. It is shown also that for nano-grained materials the n-type conductivity should be observed. The effect of impurities segregating to the grain boundaries in nano-structured PbTe is also discussed. - Highlights: • Bulk and nano-grained TE materials were analyzed by DFT. • The electronic effects on both PbTe and TiNiSn were demonstrated. • The role of impurities on the conductivity type was analyzed. • Interfacial states in nano-grained PbTe affect the conductivity type.

  5. Thermoelectric Materials Evaluation Program. Annual technical report for fiscal year 1979

    International Nuclear Information System (INIS)

    Hinderman, J.D.

    1979-10-01

    Optimization was initiated with respect to performance, operating temperatures, and thermoelectric properties of an N-type material based on rare earth (neodymium and gadolinium) selenide technology. Effort was expanded to experimentally describe the chemical, electrical and physical behavior of P-type thermoelectric material over a range of temperatures. Emphasis was changed in P-type material research from basic properties to sublimation suppression by wrapping, and to the understanding of contact resistance problems at the hot end. Analytical performance calculations were made as an aid in couple development. In the area of module development an evaluation of the reduction of bypass-heat loss was made and module M-22R was placed on test. Parts were fabricated for M23R. Data on long term operating characteristics, ingradient compatibility, and reliability of elements and couples was obtained

  6. Thermoelectricity in liquid crystals

    Science.gov (United States)

    Mohd Said, Suhana; Nordin, Abdul Rahman; Abdullah, Norbani; Balamurugan, S.

    2015-09-01

    The thermoelectric effect, also known as the Seebeck effect, describes the conversion of a temperature gradient into electricity. A Figure of Merit (ZT) is used to describe the thermoelectric ability of a material. It is directly dependent on its Seebeck coefficient and electrical conductivity, and inversely dependent on its thermal conductivity. There is usually a compromise between these parameters, which limit the performance of thermoelectric materials. The current achievement for ZT~2.2 falls short of the expected threshold of ZT=3 to allow its viability in commercial applications. In recent times, advances in organic thermoelectrics been significant, improving by over 3 orders of magnitude over a period of about 10 years. Liquid crystals are newly investigated as candidate thermoelectric materials, given their low thermal conductivity, inherent ordering, and in some cases, reasonable electrical conductivity. In this work the thermoelectric behaviour of a discotic liquid crystal, is discussed. The DLC was filled into cells coated with a charge injector, and an alignment of the columnar axis perpendicular to the substrate was allowed to form. This thermoelectric behavior can be correlated to the order-disorder transition. A reasonable thermoelectric power in the liquid crystal temperature regime was noted. In summary, thermoelectric liquid crystals may have the potential to be utilised in flexible devices, as a standalone power source.

  7. Thermoelectric skutterudite compositions and methods for producing the same

    Science.gov (United States)

    Ren, Zhifeng; Yang, Jian; Yan, Xiao; He, Qinyu; Chen, Gang; Hao, Qing

    2014-11-11

    Compositions related to skutterudite-based thermoelectric materials are disclosed. Such compositions can result in materials that have enhanced ZT values relative to one or more bulk materials from which the compositions are derived. Thermoelectric materials such as n-type and p-type skutterudites with high thermoelectric figures-of-merit can include materials with filler atoms and/or materials formed by compacting particles (e.g., nanoparticles) into a material with a plurality of grains each having a portion having a skutterudite-based structure. Methods of forming thermoelectric skutterudites, which can include the use of hot press processes to consolidate particles, are also disclosed. The particles to be consolidated can be derived from (e.g., grinded from), skutterudite-based bulk materials, elemental materials, other non-Skutterudite-based materials, or combinations of such materials.

  8. An additive approach to low temperature zero pressure sintering of bismuth antimony telluride thermoelectric materials

    Science.gov (United States)

    Catlin, Glenn C.; Tripathi, Rajesh; Nunes, Geoffrey; Lynch, Philip B.; Jones, Howard D.; Schmitt, Devin C.

    2017-03-01

    This paper presents an additive-based approach to the formulation of thermoelectric materials suitable for screen printing. Such printing processes are a likely route to such thermoelectric applications as micro-generators for wireless sensor networks and medical devices, but require the development of materials that can be sintered at ambient pressure and low temperatures. Using a rapid screening process, we identify the eutectic combination of antimony and tellurium as an additive for bismuth-antimony-telluride that enables good thermoelectric performance without a high pressure step. An optimized composite of 15 weight percent Sb7.5Te92.5 in Bi0.5Sb1.5Te3 is scaled up and formulated into a screen-printable paste. Samples fabricated from this paste achieve a thermoelectric figure of merit (ZT) of 0.74 using a maximum processing temperature of 748 K and a total thermal processing budget of 12 K-hours.

  9. Frequency-domain Harman technique for rapid characterization of bulk and thin film thermoelectric materials

    Science.gov (United States)

    Moran, Samuel

    Nanostructured thermoelectrics, often in the form of thin films, may potentially improve the generally poor efficiency of bulk thermoelectric power generators and coolers. In order to characterize the efficiency of these new materials it is necessary to measure their thermoelectric figure of merit, ZT. The only direct measurement of ZT is based on the Harman technique and relies on measuring the voltage drop across a sample subjected to a passing continuous current. Application of this technique to thin films is currently carried out as a time-domain measurement of the voltage as the thermal component decays after switching off an applied voltage. This work develops a technique for direct simultaneous measurement of figure of merit and Seebeck coefficient from the harmonic response of a thermoelectric material under alternating current excitation. A thermocouple mounted on the top surface measures voltage across the device as the frequency of the applied voltage is varied. A thermal model allows the sample thermal conductivity to also be determined and shows good agreement with measurements. This technique provides improved signal-to-noise ratio and accuracy compared to time-domain ZT measurements for comparable conditions while simultaneously measuring Seebeck coefficient. The technique is applied to both bulk and thin film thermoelectric samples.

  10. Development of a prototype thermoelectric space cooling system using phase change material to improve the performance

    Science.gov (United States)

    Zhao, Dongliang

    The thermoelectric cooling system has advantages over conventional vapor compression cooling devices, including compact in size, light in weight, high reliability, no mechanical moving parts, no refrigerant, being powered by direct current, and easily switching between cooling and heating modes. However, it has been long suffering from its relatively high cost and low energy efficiency, which has restricted its usage to niche applications, such as space missions, portable cooling devices, scientific and medical equipment, where coefficient of performance (COP) is not as important as reliability, energy availability, and quiet operation environment. Enhancement of thermoelectric cooling system performance generally relies on two methods: improving thermoelectric material efficiency and through thermoelectric cooling system thermal design. This research has been focused on the latter one. A prototype thermoelectric cooling system integrated with phase change material (PCM) thermal energy storage unit for space cooling has been developed. The PCM thermal storage unit used for cold storage at night, functions as the thermoelectric cooling system's heat sink during daytime's cooling period and provides relatively lower hot side temperature for the thermoelectric cooling system. The experimental test of the prototype system in a reduced-scale chamber has realized an average cooling COP of 0.87, with the maximum value of 1.22. Another comparison test for efficacy of PCM thermal storage unit shows that 35.3% electrical energy has been saved from using PCM for the thermoelectric cooling system. In general, PCM faces difficulty of poor thermal conductivity at both solid and liquid phases. This system implemented a finned inner tube to increase heat transfer during PCM charging (melting) process that directly impacts thermoelectric system's performance. A simulation tool for the entire system has been developed including mathematical models for a single thermoelectric module

  11. A setup for measuring the Seebeck coefficient and the electrical resistivity of bulk thermoelectric materials

    Science.gov (United States)

    Fu, Qiang; Xiong, Yucheng; Zhang, Wenhua; Xu, Dongyan

    2017-09-01

    This paper presents a setup for measuring the Seebeck coefficient and the electrical resistivity of bulk thermoelectric materials. The sample holder was designed to have a compact structure and can be directly mounted in a standard cryostat system for temperature-dependent measurements. For the Seebeck coefficient measurement, a thin bar-shaped sample is mounted bridging two copper bases; and two ceramic heaters are used to generate a temperature gradient along the sample. Two type T thermocouples are used to determine both temperature and voltage differences between two widely separated points on the sample. The thermocouple junction is flattened into a disk and pressed onto the sample surface by using a spring load. The flexible fixation method we adopted not only simplifies the sample mounting process but also prevents thermal contact deterioration due to the mismatch of thermal expansion coefficients between the sample and other parts. With certain modifications, the sample holder can also be used for four-probe electrical resistivity measurements. High temperature measurements are essential for thermoelectric power generation. The experimental system we developed is capable of measuring the Seebeck coefficient and the electrical resistivity of bulk thermoelectric materials in a wide temperature range from 80 to 500 K, which can be further extended to even higher temperatures. Measurements on two standard materials, constantan and nickel, confirmed the accuracy and the reliability of the system.

  12. Electronic cooling using thermoelectric devices

    Energy Technology Data Exchange (ETDEWEB)

    Zebarjadi, M., E-mail: m.zebarjadi@rutgers.edu [Department of Mechanical and Aerospace Engineering, Rutgers University, Piscataway, New Jersey 08854 (United States); Institute of Advanced Materials, Devices, and Nanotechnology, Rutgers University, Piscataway, New Jersey 08854 (United States)

    2015-05-18

    Thermoelectric coolers or Peltier coolers are used to pump heat in the opposite direction of the natural heat flux. These coolers have also been proposed for electronic cooling, wherein the aim is to pump heat in the natural heat flux direction and from hot spots to the colder ambient temperature. In this manuscript, we show that for such applications, one needs to use thermoelectric materials with large thermal conductivity and large power factor, instead of the traditionally used high ZT thermoelectric materials. We further show that with the known thermoelectric materials, the active cooling cannot compete with passive cooling, and one needs to explore a new set of materials to provide a cooling solution better than a regular copper heat sink. We propose a set of materials and directions for exploring possible materials candidates suitable for electronic cooling. Finally, to achieve maximum cooling, we propose to use thermoelectric elements as fins attached to copper blocks.

  13. Avoided crossing of rattler modes in thermoelectric materials

    DEFF Research Database (Denmark)

    Christensen, Mogens; Abrahamsen, Asger Bech; Christensen, Niels Bech

    2008-01-01

    thermoelectric materials, and the challenge is to limit the conduction of heat by phonons, without simultaneously reducing the charge transport. This is named the 'phonon glass-electron crystal' concept and may be realized in host-guest systems. The guest entities are believed to have independent oscillations......, so-called rattler modes, which scatter the acoustic phonons and reduce the thermal conductivity. We have investigated the phonon dispersion relation in the phonon glass-electron crystal material Ba8Ga16Ge30 using neutron triple-axis spectroscopy. The results disclose unambiguously the theoretically...

  14. Scandium-doped zinc cadmium oxide as a new stable n-type oxide thermoelectric material

    DEFF Research Database (Denmark)

    Han, Li; Christensen, Dennis Valbjørn; Bhowmik, Arghya

    2016-01-01

    Scandium-doped zinc cadmium oxide (Sc-doped ZnCdO) is proposed as a new n-type oxide thermoelectric material. The material is sintered in air to maintain the oxygen stoichiometry and avoid instability issues. The successful alloying of CdO with ZnO at a molar ratio of 1 : 9 significantly reduced...... is a good candidate for improving the overall conversion efficiencies in oxide thermoelectric modules. Meanwhile, Sc-doped ZnCdO is robust in air at high temperatures, whereas other n-type materials, such as Al-doped ZnO, will experience rapid degradation of their electrical conductivity and ZT....

  15. Efficient Space Hardy Thermoelectric Materials with Broad Temperature Range, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The goal of this work is developing new thermoelectric materials for use in fabricating solid state cooling devices and electrical power generators, which are 200 to...

  16. An oxide-based thermoelectric generator: Transversal thermoelectric strip-device

    Science.gov (United States)

    Teichert, S.; Bochmann, A.; Reimann, T.; Schulz, T.; Dreßler, C.; Töpfer, J.

    2015-07-01

    A special design of an oxide-based transversal thermoelectric device utilizing thermoelectric oxides in combination with a ceramic multilayer technology is proposed. Metal strips within the ceramic matrix replace the tilted stack of alternating layers used in artificial anisotropic transversal thermoelectric devices. Numerical three-dimensional simulations of both device types reveal better thermoelectric performance data for the device with metal stripes. A monolithic transversal strip-device based on the material combination La1.97Sr0.03CuO4/Ag6Pd1 was prepared and electrically characterized. A maximum power output of 4.0 mW was determined at ΔT = 225 K for the monolithic device. The observed results are in remarkable agreement with three-dimensional numerical simulations utilizing the transport parameters of the two materials and the geometry data of the device.

  17. Thermoelectricity for future sustainable energy technologies

    Directory of Open Access Journals (Sweden)

    Weidenkaff Anke

    2017-01-01

    Full Text Available Thermoelectricity is a general term for a number of effects describing the direct interconversion of heat and electricity. Thermoelectric devices are therefore promising, environmental-friendly alternatives to conventional power generators or cooling units. Since the mid-90s, research on thermoelectric properties and their applications has steadily increased. In the course of years, the development of high-temperature resistant TE materials and devices has emerged as one of the main areas of interest focusing both on basic research and practical applications. A wide range of innovative and cost-efficient material classes has been studied and their properties improved. This has also led to advances in synthesis and metrology. The paper starts out with thermoelectric history, basic effects underlying thermoelectric conversion and selected examples of application. The main part focuses on thermoelectric materials including an outline of the design rules, a review on the most common materials and the feasibility of improved future high-temperature thermoelectric converters.

  18. The thermoelectric performance of bulk three-dimensional graphene

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Zhi, E-mail: yangzhi@tyut.edu.cn [Key Lab of Advanced Transducers and Intelligent Control System, Ministry of Education and Shanxi Province, Taiyuan University of Technology, Taiyuan 030024 (China); College of Physics and Optoelectronics, Taiyuan University of Technology, Taiyuan 030024 (China); Lan, Guoqiang; Ouyang, Bin [Department of Mining and Materials Engineering, McGill University, Montreal H3A 0C5 (Canada); Xu, Li-Chun; Liu, Ruiping [College of Physics and Optoelectronics, Taiyuan University of Technology, Taiyuan 030024 (China); Liu, Xuguang, E-mail: liuxuguang@tyut.edu.cn [Key Lab of Interface Science and Engineering in Advanced Materials, Ministry of Education, Taiyuan University of Technology, Taiyuan 030024 (China); College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Song, Jun [Department of Mining and Materials Engineering, McGill University, Montreal H3A 0C5 (Canada)

    2016-11-01

    The electronic and thermoelectric properties of a new carbon bulk material, three-dimensional (3D) graphene, are investigated in this study. Our results show that 3D graphene has unique electronic structure, i.e., near the Fermi level there exist Dirac cones. More importantly, the thermoelectric performance of 3D graphene is excellent, at room temperature the thermoelectric figure of merit (ZT) is 0.21, an order of magnitude higher than that of graphene. By introducing line defects, the ZT of 3D graphene could be enhanced to 1.52, indicating 3D graphene is a powerful candidate for constructing novel thermoelectric materials. - Highlights: • There exist Dirac cones in three-dimensional (3D) graphene. • The thermoelectric performance of 3D graphene is excellent. • The defective 3D graphene has better thermoelectric performance.

  19. Solar-TEP - Development of materials for thermo-electric power generators; SOLAR-TEP - Materialentwicklung fuer solarthermoelektrische Stromerzeuger - Schlussbericht 2008

    Energy Technology Data Exchange (ETDEWEB)

    Robert, R.; Weidenkaff, A.

    2008-06-15

    This final report for the Swiss Federal Office of Energy (SFOE) reports on the development of materials for thermo-electric power generators. Cobaltate phases are discussed as being suitable materials for thermoelectric applications at high temperatures. These potential thermoelectric materials are characterised with respect to their crystal structure, microstructure, composition, and thermal stability. The Seebeck coefficient, thermal conductivity and electrical resistivity of polycrystalline cobaltates with perovskite-type and layered-cobaltite structure are evaluated for a wide temperature range. The large Seebeck coefficient exhibited by both perovskite-type and layered cobaltite phases is analysed using the Heikes formula. The work is illustrated with results obtained for various materials in graphical form.

  20. Efficient Space Hardy Thermoelectric Materials with Broad Temperature Range, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — The goal of this work is to develop new thermoelectric materials for use in fabricating solid state cooling devices and electrical power generators, which are 200 to...

  1. New Materials for High Temperature Thermoelectric Power Generation

    Energy Technology Data Exchange (ETDEWEB)

    Kauzlarich, Susan [Univ. of California, Davis, CA (United States)

    2016-02-03

    The scope of this proposal was to develop two new high ZT materials with enhanced properties for the n- and p-leg of a thermoelectric device capable of operating at a maximum temperature of 1275 K and to demonstrate the efficiency in a working device. Nanostructured composites and new materials based on n– and p–type nanostructured Si1-xGex (ZT1273K ~ 1) and the recently discovered p–type high temperature Zintl phase material, Yb14MnSb11 (ZT1273K ~1) were developed and tested in a working device.

  2. Studies of bulk materials for thermoelectric cooling

    Energy Technology Data Exchange (ETDEWEB)

    Sharp, J W; Nolas, G S; Volckmann, E H

    1997-07-01

    The authors discuss ongoing work in three areas of thermoelectric materials research: (1) broad band semiconductors featuring anion networks, (2) filled skutterudites, and (3) polycrystalline Bi-Sb alloys. Key results include: a preliminary evaluation of a previously untested ternary semiconductor, KSnSb; the first reported data in which Sn is used as a charge compensator in filled antimonide skutterudites; the finding that Sn doping does not effect polycrystalline Bi{sub 1{minus}x}Sb{sub x} as it does single crystal samples.

  3. Thermoelectrics and its energy harvesting

    National Research Council Canada - National Science Library

    Rowe, David Michael

    2012-01-01

    .... 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...

  4. Nanostructured Thermoelectric Oxides for Energy Harvesting Applications

    KAUST Repository

    Abutaha, Anas I.

    2015-01-01

    of thermoelectrics are still limited to one materials system, namely SiGe, since the traditional thermoelectric materials degrade and oxidize at high temperature. Therefore, oxide thermoelectrics emerge as a promising class of materials since they can operate

  5. Green thermoelectrics: Observation and analysis of plant thermoelectric response

    Directory of Open Access Journals (Sweden)

    Goupil Christophe

    2016-01-01

    Full Text Available Plants are sensitive to thermal and electrical effects; yet the coupling of both, known as thermoelectricity, and its quantitative measurement in vegetal systems never were reported. We recorded the thermoelectric response of bean sprouts under various thermal conditions and stress. The obtained experimental data unambiguously demonstrate that a temperature difference between the roots and the leaves of a bean sprout induces a thermoelectric voltage between these two points. Basing our analysis of the data on the force-flux formalism of linear response theory, we found that the strength of the vegetal equivalent to the thermoelectric coupling is one order of magnitude larger than that in the best thermoelectric materials. Experimental data also show the importance of the thermal stress variation rate in the plant’s electrophysiological response. therefore, thermoelectric effects are sufficiently important to partake in the complex and intertwined processes of energy and matter transport within plants.

  6. Encapsulation of high temperature thermoelectric modules

    Energy Technology Data Exchange (ETDEWEB)

    Salvador, James R.; Sakamoto, Jeffrey; Park, Youngsam

    2017-07-11

    A method of encapsulating a thermoelectric device and its associated thermoelectric elements in an inert atmosphere and a thermoelectric device fabricated by such method are described. These thermoelectric devices may be intended for use under conditions which would otherwise promote oxidation of the thermoelectric elements. The capsule is formed by securing a suitably-sized thin-walled strip of oxidation-resistant metal to the ceramic substrates which support the thermoelectric elements. The thin-walled metal strip is positioned to enclose the edges of the thermoelectric device and is secured to the substrates using gap-filling materials. The strip, substrates and gap-filling materials cooperatively encapsulate the thermoelectric elements and exclude oxygen and water vapor from atmospheric air so that the elements may be maintained in an inert, non-oxidizing environment.

  7. Model Thermoelectric Generator TEG Small Modular As Micro Electricity Plant At Indonesia Part 1 Design And Material

    Directory of Open Access Journals (Sweden)

    Kisman M. Mahmud

    2015-08-01

    Full Text Available Thermoelectrically Generator TEG can generate electricity from the temperature difference between hot and cold at the junction thermoelectric module with two different semiconductor materials there will be a flow of current through the junction so as to produce a voltage. This principle uses the Seebeck effect thermoelectric generator as a base. By using these principles this study was conducted to determine the potential of the electric energy of the two Peltier modules which would be an alternative source for micro electricity plant using heat from methylated. The focus of this research is to design a model TEG Thermoelectric Generator Small Modular to produce the kind of material that is optimum for a TEG on the simulation Computer Aided Design CAD with a variety of four different materials that Bi2Te3 Bismuth Telluride PbTe-BiTe CMO-32 -62S Cascade and CMO-32-62S Calcium Manganese Oxide to its cold side using the heat sink fan and simulating heat aluminum plate attached to the hot side of the TEG modules with heat source of methylated. Model simulation results on TEG Small Modular micro electrical plant material obtained CMO-32-62S Cascade thermal material that has a value greater than 3 other material.

  8. Thermoelectric Energy Harvesting Using Phase Change Materials (PCMs) in High Temperature Environments in Aircraft

    Science.gov (United States)

    Elefsiniotis, A.; Becker, Th.; Schmid, U.

    2014-06-01

    Wireless, energy-autonomous structural health-monitoring systems in aircraft have the potential of reducing total maintenance costs. Thermoelectric energy harvesting, which seems the best choice for creating truly autonomous health monitoring sensors, is the principle behind converting waste heat to useful electrical energy through the use of thermoelectric generators. To enhance the temperature difference across the two sides of a thermoelectric generator, i.e. increasing heat flux and energy production, a phase change material acting as thermal mass is attached on one side of the thermoelectric generators while the other side is placed on the aircraft structure. The application area under investigation for this paper is the pylon aft fairing, located near the engine of an aircraft, with temperatures reaching on the inside up to 350 °C. Given these harsh operational conditions, the performance of a device, containing erythritol as a phase change material, is evaluated. The harvested energy reaching values up to 81.4 J can be regulated by a power management module capable of storing the excess energy and recovering it from the medium powering a sensor node and a wireless transceiver.

  9. Mechanical properties of BixSb2−xTe3 nanostructured thermoelectric material

    International Nuclear Information System (INIS)

    Li, G; Gadelrab, K R; Souier, T; Chiesa, M; Potapov, P L; Chen, G

    2012-01-01

    Research on thermoelectric (TE) materials has been focused on their transport properties in order to maximize their overall performance. Mechanical properties, which are crucial for system reliability, are often overlooked. The recent development of a new class of high-performance, low-dimension thermoelectric materials calls for a better understanding of their mechanical behavior to achieve the desired system reliability. In the present study we investigate the mechanical behavior of nanostructure bulk TE material p-type Bi x Sb 2−x Te 3 by means of nanoindentation and 3D finite element analysis. The Young’s modulus of the material was estimated by the Oliver–Pharr (OP) method and by means of numerically assisted nanoindentation analysis yielding comparable values about 40 GPa. Enhanced hardness and yield strength can be predicted for this nanostructured material. Microstructure is studied and correlation with mechanical properties is discussed. (paper)

  10. Performance evaluation of a thermoelectric energy harvesting device using various phase change materials

    International Nuclear Information System (INIS)

    Elefsiniotis, A; Becker, T; Kiziroglou, M E; Wright, S W; Toh, T T; Mitcheson, P D; Yeatman, E M; Schmid, U

    2013-01-01

    This paper compares the performance of a group of organic and inorganic phase change materials for a heat storage thermoelectric energy harvesting device. The device consists of thermoelectric generators and a closed container filled with a phase change material. One side of the generators is mounted on the aircraft fuselage and the other to the thermal mass. The group of inorganic and organic phase change materials was tested across two temperature ranges. These ranges are defined as ''positive'' and ''negative'', with the former being a sweep from +35°C to −5°C and the latter being a sweep from +5°C to −35°C. The performance in terms of electrical energy output and power produced is examined in detail for each group of materials

  11. Thermoelectric and mechanical properties of spark plasma sintered Cu{sub 3}SbSe{sub 3} and Cu{sub 3}SbSe{sub 4}: Promising thermoelectric materials

    Energy Technology Data Exchange (ETDEWEB)

    Tyagi, Kriti; Gahtori, Bhasker; Bathula, Sivaiah; Toutam, Vijaykumar; Sharma, Sakshi; Singh, Niraj Kumar; Dhar, Ajay, E-mail: adhar@nplindia.org [CSIR-Network of Institutes for Solar Energy, Materials Physics and Engineering, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Road, New Delhi 110012 (India)

    2014-12-29

    We report the synthesis of thermoelectric compounds, Cu{sub 3}SbSe{sub 3} and Cu{sub 3}SbSe{sub 4}, employing the conventional fusion method followed by spark plasma sintering. Their thermoelectric properties indicated that despite its higher thermal conductivity, Cu{sub 3}SbSe{sub 4} exhibited a much larger value of thermoelectric figure-of-merit as compared to Cu{sub 3}SbSe{sub 3}, which is primarily due to its higher electrical conductivity. The thermoelectric compatibility factor of Cu{sub 3}SbSe{sub 4} was found to be ∼1.2 as compared to 0.2 V{sup −1} for Cu{sub 3}SbSe{sub 3} at 550 K. The results of the mechanical properties of these two compounds indicated that their microhardness and fracture toughness values were far superior to the other competing state-of-the-art thermoelectric materials.

  12. Tuning the Transport Properties of Layered Materials for Thermoelectric Applications using First-Principles Calculations

    KAUST Repository

    Saeed, Yasir

    2014-01-01

    opening and reduction of the lattice thermal conductivity. Bi2Se3 (bulk and thin film) has a larger bandgap then the well-known thermoelectric material Bi2Te3, which is important at high temperature. The structural stability, electronic structure

  13. High Performance High Temperature Thermoelectric Composites with Metallic Inclusions

    Science.gov (United States)

    Ma, James M. (Inventor); Bux, Sabah K. (Inventor); Fleurial, Jean-Pierre (Inventor); Ravi, Vilupanur A. (Inventor); Firdosy, Samad A. (Inventor); Star, Kurt (Inventor); Kaner, Richard B. (Inventor)

    2017-01-01

    The present invention provides a composite thermoelectric material. The composite thermoelectric material can include a semiconductor material comprising a rare earth metal. The atomic percent of the rare earth metal in the semiconductor material can be at least about 20%. The composite thermoelectric material can further include a metal forming metallic inclusions distributed throughout the semiconductor material. The present invention also provides a method of forming this composite thermoelectric material.

  14. Solid Liquid Interdiffusion Bonding of Zn4Sb3 Thermoelectric Material with Cu Electrode

    Science.gov (United States)

    Lin, Y. C.; Lee, K. T.; Hwang, J. D.; Chu, H. S.; Hsu, C. C.; Chen, S. C.; Chuang, T. H.

    2016-10-01

    The ZnSb intermetallic compound may have thermoelectric applications because it is low in cost and environmentally friendly. In this study, a Zn4Sb3 thermoelectric element coated with a Ni barrier layer and a Ag reaction layer was bonded with a Ag-coated Cu electrode using a Ag/Sn/Ag solid-liquid interdiffusion bonding process. The results indicated that a Ni5Zn21 intermetallic phase formed easily at the Zn4Sb3/Ni interface, leading to sound adhesion. In addition, Sn film was found to react completely with the Ag layer to form a Ag3Sn intermetallic layer having a melting point of 480°C. The resulting Zn4Sb3 thermoelectric module can be applied at the optimized operation temperature (400°C) of Zn4Sb3 material as a thermoelectric element. The bonding strengths ranged from 14.9 MPa to 25.0 MPa, and shear tests revealed that the Zn4Sb3/Cu-joints fractured through the interior of the thermoelectric elements.

  15. Powder metallurgical processing of functionally graded p-Pb1-x Sn x Te materials for thermoelectric applications

    International Nuclear Information System (INIS)

    Gelbstein, Y.; Dashevsky, Z.; Dariel, M.P.

    2007-01-01

    Lead tin telluride-based compounds are p-type materials for thermoelectric applications, in the 50-600 deg. C temperature range. The electronic transport properties of PbTe and Pb 1- x Sn x Te materials are strongly dependent on the processing approach. Powder metallurgy is a suitable approach for the preparation of Functionally graded materials (FGMs) but its effects on the electronic properties have to be carefully checked. Powder metallurgical processing may introduce atomic defects and local strains into the material and, thereby, alter the carrier concentration. Such material may be in non-equilibrium conditions at the operating temperature with unstable thermoelectric properties. This effect can be reduced and eliminated by appropriate annealing procedures. In FGMs, annealing up to the stabilization of the thermoelectric properties is mandatory for achieving the desired carrier concentration profile along the sample. The design procedures of the FGMs, as well as the annealing effects on cold compacted and sintered Pb 1- x Sn x Te samples are described in details

  16. Arsenene and Antimonene: Two-Dimensional Materials with High Thermoelectric Figures of Merit

    KAUST Repository

    Sharma, S.; Sarath Kumar, S. R.; Schwingenschlö gl, Udo

    2017-01-01

    We study the thermoelectric properties of As and Sb monolayers (arsenene and antimonene) using density-functional theory and the semiclassical Boltzmann transport approach. The materials show large band gaps combined with low lattice thermal

  17. Thermoelectric properties of PbSe₀.₅Te₀.₅: x (PbI₂) with endotaxial nanostructures: a promising n-type thermoelectric material.

    Science.gov (United States)

    Rawat, P K; Paul, B; Banerji, P

    2013-05-31

    In the present investigation, we report on the thermoelectric properties of PbSe₀.₅Te₀.₅: x (PbI₂) from room temperature to 625 K. High-resolution transmission electron micrographs of the samples reveal endotaxial nanostructures embedded in a PbSe₀.₅Te₀.₅ matrix. The combined effect of mass fluctuation and nanostructures reduces the thermal conductivity to a great extent compared to PbTe and PbSe, without affecting the carrier mobility. As a result, a thermoelectric figure of merit with a value of 1.5 is achieved at 625 K. This value is significantly higher than that of the available state-of-the-art n-type materials.

  18. Relationship between the merit factor of thermoelectric materials and the air conditioning unit of urban electric cars

    International Nuclear Information System (INIS)

    Buffet, J.

    1994-01-01

    The main benefit of electric cars is to reduce air pollution in cities that is thus desirable to equip them with non polluting air conditioning units and this rules out frigorific compressors operating with CFC. The planned replacement of CFC by HFC is at best an interim solution. The best solution is certainly to use thermoelectric air conditioning units, which are inherently pollution-free. However, these have a fairly low COPF when compared to traditional compressor units. We study the relationship between the cooling of the interior of urban electric cars and the merit factor of the thermoelectric material in their Peltier unit. This should help provide concrete target properties of future T E materials. copyright 1995 American Institute of Physics

  19. Integrating Phase-Change Materials into Automotive Thermoelectric Generators

    Science.gov (United States)

    Klein Altstedde, Mirko; Rinderknecht, Frank; Friedrich, Horst

    2014-06-01

    Because the heat emitted by conventional combustion-engine vehicles during operation has highly transient properties, automotive thermoelectric generators (TEG) are intended for a particular operating state (design point). This, however, leads to two problems. First, whenever the combustion engine runs at low load, the maximum operating temperature cannot be properly utilised; second, a combustion engine at high load requires partial diversion of exhaust gas away from the TEG to protect the thermoelectric modules. An attractive means of stabilising dynamic exhaust behaviour (thereby keeping the TEG operating status at the design point for as long as possible) is use of latent heat storage, also known as phase-change materials (PCM). By positioning PCM between module and exhaust heat conduit, and choosing a material with a phase-change temperature matching the module's optimum operating temperature, it can be used as heat storage. This paper presents results obtained during examination of the effect of integration of latent heat storage on the potential of automotive TEG to convert exhaust heat. The research resulted in the development of a concept based on the initial integration idea, followed by proof of concept by use of a specially created prototype. In addition, the potential amount of energy obtained by use of a PCM-equipped TEG was calculated. The simulations indicated a significant increase in electrical energy was obtained in the selected test cycle.

  20. Materials Research Department Annual report 1998

    Energy Technology Data Exchange (ETDEWEB)

    Winther, Grethe; Hansen, N [eds.

    1999-04-01

    Selected activities of the Materials Research Department at Risoe National Laboratory during 1998 are described. The scientific work is presented in five chapters: Materials Science, Materials Engineering, Materials Technology, Materials Chemistry and Fusion Materials. A survey is given of the Departments collaboration with national and international industries and research institutions. Furthermore, the main figures outlining the funding and expenditure of the Department are given. Lists of staff members, visiting scientists and educational activities are included. (au) 165 refs.

  1. Materials Research Department Annual report 1998

    International Nuclear Information System (INIS)

    Winther, Grethe; Hansen, N.

    1999-04-01

    Selected activities of the Materials Research Department at Risoe National Laboratory during 1998 are described. The scientific work is presented in five chapters: Materials Science, Materials Engineering, Materials Technology, Materials Chemistry and Fusion Materials. A survey is given of the Departments collaboration with national and international industries and research institutions. Furthermore, the main figures outlining the funding and expenditure of the Department are given. Lists of staff members, visiting scientists and educational activities are included. (au)

  2. Thermoelectric transport properties of BaBiTe{sub 3}-based materials

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Yiming; Zhao, Li-Dong, E-mail: zhaolidong@buaa.edu.cn

    2017-05-15

    BaBiTe{sub 3}, a material with low thermal conductivity, is an inferior thermoelectric material due to the poor electrical properties originated from its narrow band gap. We choose two types of dopants, K and La, trying to optimize its electrical transport properties. The minority carriers, which harm the Seebeck coefficient in this system, are suppressed by La doping. With the increase of both electrical conductivity and Seebeck coefficient, the power factor of 3% La doped BaBiTe{sub 3} reaches 3.7 μW cm{sup −1} K{sup −2} which increased by 40% from undoped BaBiTe{sub 3}. Besides high power factor, the thermal conductivity is also reduced in it. Eventually, a high ZT value, 0.25 at 473 K, for n-type BaBiTe{sub 3} is achieved in 3% La doped BaBiTe{sub 3}. - Graphical abstract: BaBiTe{sub 3} possesses a low thermal conductivity. However, it is an inferior thermoelectric material due to the poor electrical properties originated from its narrow band gap. A high ZT value of 0.25 at 473 K for n-type BaBiTe{sub 3} can be achieved through optimizing electrical transport properties via La doping. - Highlights: • BaBiTe{sub 3} is an analogue of these promising thermoelectric materials: such as CsBi{sub 4}Te{sub 6} and K{sub 2}Bi{sub 8}Se{sub 13}, etc. • BaBiTe{sub 3} possesses a low thermal conductivity. • La is an effective dopant to enhance electrical transport properties. • A high ZT value of 0.25 at 473 K can be achieved in n-type La-doped BaBiTe{sub 3}.

  3. Selection and evaluation of materials for thermoelectric applications II

    Energy Technology Data Exchange (ETDEWEB)

    Sharp, J W

    1997-07-01

    In good thermoelectrics phonons have short mean free paths, and charge carriers have long ones. The other requirements are a multivalley band structure and a band gap greater than 0.1 eV for the 200 to 300 K temperature range. The author discusses the use of solid state physics and chemistry concepts, along with atomic and crystal structure data, to select the new materials most likely to meet these criteria.

  4. Test system for thermoelectric modules and materials

    Czech Academy of Sciences Publication Activity Database

    Hejtmánek, Jiří; Knížek, Karel; Švejda, V.; Horna, P.; Sikora, M.

    2014-01-01

    Roč. 43, č. 10 (2014), s. 3726-3732 ISSN 0361-5235 R&D Projects: GA ČR GA13-17538S Institutional support: RVO:68378271 Keywords : thermoelectric power module * automatic thermoelectric testing setup * heat flow measurement * power generation * heat recovery Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.798, year: 2014

  5. A 3D TCAD simulation of a thermoelectric module configured for thermoelectric power generation, cooling and heating

    Science.gov (United States)

    Gould, C. A.; Shammas, N. Y. A.; Grainger, S.; Taylor, I.; Simpson, K.

    2012-06-01

    This paper documents the 3D modeling and simulation of a three couple thermoelectric module using the Synopsys Technology Computer Aided Design (TCAD) semiconductor simulation software. Simulation results are presented for thermoelectric power generation, cooling and heating, and successfully demonstrate the basic thermoelectric principles. The 3D TCAD simulation model of a three couple thermoelectric module can be used in the future to evaluate different thermoelectric materials, device structures, and improve the efficiency and performance of thermoelectric modules.

  6. Mg2BIV: Narrow Bandgap Thermoelectric Semiconductors

    Science.gov (United States)

    Kim, Il-Ho

    2018-05-01

    Thermoelectric materials can convert thermal energy directly into electric energy and vice versa. The electricity generation from waste heat via thermoelectric devices can be considered as a new energy source. For instance, automotive exhaust gas and all industrial processes generate an enormous amount of waste heat that can be converted to electricity by using thermoelectric devices. Magnesium compound Mg2BIV (BIV = Si, Ge or Sn) has a favorable combination of physical and chemical properties and can be a good base for the development of new efficient thermoelectrics. Because they possess similar properties to those of group BIV elemental semiconductors, they have been recognized as good candidates for thermoelectric applications. Mg2Si, Mg2Ge and Mg2Sn with an antifluorite structure are narrow bandgap semiconductors with indirect band gaps of 0.77 eV, 0.74 eV, and 0.35 eV, respectively. Mg2BIV has been recognized as a promising material for thermoelectric energy conversion at temperatures ranging from 500 K to 800 K. Compared to other thermoelectric materials operating in the similar temperature range, such as PbTe and filled skutterudites, the important aspects of Mg2BIV are non-toxic and earth-abundant elements. Based on classical thermoelectric theory, the material factor β ( m* / m e)3/2μκ L -1 can be utilized as the criterion for thermoelectric material selection, where m* is the density-of-states effective mass, me is the mass of an electron, μ is the carrier mobility, and κL is the lattice thermal conductivity. The β for magnesium silicides is 14, which is very high compared to 0.8 for iron silicides, 1.4 for manganese silicides, and 2.6 for silicon-germanium alloys. In this paper, basic phenomena of thermoelectricity and transport parameters for thermoelectric materials were briefly introduced, and thermoelectric properties of Mg2BIV synthesized by using a solid-state reaction were reviewed. In addition, various Mg2BIV compounds were discussed

  7. Impact of the substrate on the efficiency of thin film thermoelectric technology

    International Nuclear Information System (INIS)

    Alvarez-Quintana, J.

    2015-01-01

    Thermoelectricity is one of the simplest technologies for thermal energy conversion. Moreover, because of their relatively low efficiency, bulk thermoelectric materials are generally used in environments where their solid state nature outweighs their poor efficiency. Nevertheless, low dimensional thermoelectric materials shed a light in order to achieve higher thermoelectric performance than their bulk counterparts via quantum and spatial confinement of energy carriers. The Thermoelectric figure of merit ZT is the basic criterion for estimating the performance of thermoelectric materials. In this work, by way of an extension of the Harman method to thin films onto substrate to evaluate ZT it is shown that the solely presence of a substrate affects significantly the intrinsic value of the ZT independently of the electrical and thermal nature of the substrate. Furthermore, the model unveils that as the thickness ratio between substrate and thin film increases, the parameter ZT sharply tends to zero; this effect opens a serious problem to overcome by the thin film thermoelectric technology, especially at nanoscale. In this sense, challenges in order to engineering planar thermoelectric devices at micro/nanoscale are properly identified. - Highlights: • Extended Harman method to evaluate ZT of thin films onto substrate is presented. • ZT of thermoelectric thin films is strongly affected by substrate's nature. • Thin dielectric substrates are desirable to hold ZT in in-plane configuration. • Film/substrate thickness ratio play important role on the device performance. • Challenges to engineering planar thermoelectric devices are properly identified

  8. Nanostructured Thermoelectric Oxides for Energy Harvesting Applications

    KAUST Repository

    Abutaha, Anas I.

    2015-11-24

    As the world strives to adapt to the increasing demand for electrical power, sustainable energy sources are attracting significant interest. Around 60% of energy utilized in the world is wasted as heat. Different industrial processes, home heating, and exhausts in cars, all generate a huge amount of unused waste heat. With such a huge potential, there is also significant interest in discovering inexpensive technologies for power generation from waste heat. As a result, thermoelectric materials have become important for many renewable energy research programs. While significant advancements have been done in improving the thermoelectric properties of the conventional heavy-element based materials (such as Bi2Te3 and PbTe), high-temperature applications of thermoelectrics are still limited to one materials system, namely SiGe, since the traditional thermoelectric materials degrade and oxidize at high temperature. Therefore, oxide thermoelectrics emerge as a promising class of materials since they can operate athigher temperatures and in harsher environments compared to non-oxide thermoelectrics. Furthermore, oxides are abundant and friendly to the environment. Among oxides, crystalline SrTiO3 and ZnO are promising thermoelectric materials. The main objective of this work is therefore to pursue focused investigations of SrTiO3 and ZnO thin films and superlattices grown by pulsed laser deposition (PLD), with the goal of optimizing their thermoelectric properties by following different strategies. First, the effect of laser fluence on the thermoelectric properties of La doped epitaxial SrTiO3 films is discussed. Films grown at higher laser fluences exhibit better thermoelectric performance. Second, the role of crystal orientation in determining the thermoelectric properties of epitaxial Al doped ZnO (AZO) films is explained. Vertically aligned (c-axis) AZO films have superior thermoelectric properties compared to other films with different crystal orientations. Third

  9. Discovery of high-performance low-cost n-type Mg3Sb2-based thermoelectric materials with multi-valley conduction bands

    DEFF Research Database (Denmark)

    Zhang, Jiawei; Song, Lirong; Pedersen, Steffen Hindborg

    2017-01-01

    Widespread application of thermoelectric devices for waste heat recovery requires low-cost high-performance materials. The currently available n-type thermoelectric materials are limited either by their low efficiencies or by being based on expensive, scarce or toxic elements. Here we report a low-cost...... because of the multi-valley band behaviour dominated by a unique near-edge conduction band with a sixfold valley degeneracy. This makes Te-doped Mg3Sb1.5Bi0.5 a promising candidate for the low- and intermediate-temperature thermoelectric applications....

  10. semiconducting nanostructures: morphology and thermoelectric properties

    Science.gov (United States)

    Culebras, Mario; Torán, Raquel; Gómez, Clara M.; Cantarero, Andrés

    2014-08-01

    Semiconducting metallic oxides, especially perosvkite materials, are great candidates for thermoelectric applications due to several advantages over traditionally metallic alloys such as low production costs and high chemical stability at high temperatures. Nanostructuration can be the key to develop highly efficient thermoelectric materials. In this work, La 1- x Ca x MnO 3 perosvkite nanostructures with Ca as a dopant have been synthesized by the hydrothermal method to be used in thermoelectric applications at room temperature. Several heat treatments have been made in all samples, leading to a change in their morphology and thermoelectric properties. The best thermoelectric efficiency has been obtained for a Ca content of x=0.5. The electrical conductivity and Seebeck coefficient are strongly related to the calcium content.

  11. Review on Polymers for Thermoelectric Applications.

    Science.gov (United States)

    Culebras, Mario; Gómez, Clara M; Cantarero, Andrés

    2014-09-18

    In this review, we report the state-of-the-art of polymers in thermoelectricity. Classically, a number of inorganic compounds have been considered as the best thermoelectric materials. Since the prediction of the improvement of the figure of merit by means of electronic confinement in 1993, it has been improved by a factor of 3-4. In the mean time, organic materials, in particular intrinsically conducting polymers, had been considered as competitors of classical thermoelectrics, since their figure of merit has been improved several orders of magnitude in the last few years. We review here the evolution of the figure of merit or the power factor during the last years, and the best candidates to compete with inorganic materials. We also outline the best polymers to substitute classical thermoelectric materials and the advantages they present in comparison with inorganic systems.

  12. Material parameters for thermoelectric performance

    Indian Academy of Sciences (India)

    The thermoelectric performance of a thermoelement is ideally defined in terms of the so-called ... However, there are other parameters which are fairly good indicators ... Whereas a final deciding factor reflecting on .... matter of a future work.

  13. Optimized thermoelectric performance of the n-type half-Heusler material TiNiSn by substitution and addition of Mn

    Directory of Open Access Journals (Sweden)

    Enkhtaivan Lkhagvasuren

    2017-04-01

    Full Text Available Alloys based on the half-Heusler compound TiNiSn with the addition of Mn or with a substitution of Ti by Mn are investigated as high-temperature thermoelectric materials. In both materials an intrinsic phase separation is observed, similar to TiNiSn where Ti has been partially substituted by Hf, with increasing Mn concentration the phase separation drastically reduces the lattice thermal conductivity while the power factor is increased. The thermoelectric performance of the n-type conducting alloy can be optimized both by substitution of Ti by Mn as well as the addition of Mn.

  14. Development for environmentally friendly and highly efficient energy utilization system in fiscal 1998. Pt. 1. Research on highly efficient and effective energy utilization technology (Research on design technology for optimal system); 1998 nendo kankyo chowagata kokoritsu energy riyo system kaihatsu. 1. Kokoritsu energy yuko riyo gijutsu no kenkyu (saiteki system sekkei gijutsu no kenkyu)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-05-01

    This paper summarizes achievements of the researches during fiscal 1998 on researching a highly efficient and effective energy utilization technology. With regard to technologies to recover and convert unutilized energies, a process simulator was developed, basic internal structure was discussed by experiments and simulation, and substance migrating and heat exchanging characteristics were identified by using partial testing devices. These researches and developments were performed for the waste heat reforming and recovering systems used in chemical plants. In developing a thermoelectric generation system using low calorie exhaust gases, thermoelectric power generating materials were developed, a powder manufacturing technology was developed, a thermoelectric conversion element bulking technology was developed, a thermoelectric power generation system using porous structures was simulated, development and concept design were carried out on system element technologies. In the research and development of the thermoelectric generation system using low calorie exhaust gases, advanced materials and modules were manufactured, the modules were evaluated, and power generation systems were researched. In addition, researches were performed on energy transportation, supply and utilization technologies, and on environmental load reducing technologies. (NEDO)

  15. Soft Chemistry, Coloring and Polytypism in Filled Tetrahedral Semiconductors: Toward Enhanced Thermoelectric and Battery Materials.

    Science.gov (United States)

    White, Miles A; Medina-Gonzalez, Alan M; Vela, Javier

    2018-03-12

    Filled tetrahedral semiconductors are a rich family of compounds with tunable electronic structure, making them ideal for applications in thermoelectrics, photovoltaics, and battery anodes. Furthermore, these materials crystallize in a plethora of related structures that are very close in energy, giving rise to polytypism through the manipulation of synthetic parameters. This Minireview highlights recent advances in the solution-phase synthesis and nanostructuring of these materials. These methods enable the synthesis of metastable phases and polytypes that were previously unobtainable. Additionally, samples synthesized in solution phase have enhanced thermoelectric performance due to their decreased grain size. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Review on Polymers for Thermoelectric Applications

    Directory of Open Access Journals (Sweden)

    Mario Culebras

    2014-09-01

    Full Text Available In this review, we report the state-of-the-art of polymers in thermoelectricity. Classically, a number of inorganic compounds have been considered as the best thermoelectric materials. Since the prediction of the improvement of the figure of merit by means of electronic confinement in 1993, it has been improved by a factor of 3–4. In the mean time, organic materials, in particular intrinsically conducting polymers, had been considered as competitors of classical thermoelectrics, since their figure of merit has been improved several orders of magnitude in the last few years. We review here the evolution of the figure of merit or the power factor during the last years, and the best candidates to compete with inorganic materials. We also outline the best polymers to substitute classical thermoelectric materials and the advantages they present in comparison with inorganic systems.

  17. Effects of Fe3O4 Magnetic Nanoparticles on the Thermoelectric Properties of Heavy-Fermion YbAl3 Materials

    Science.gov (United States)

    He, Danqi; Mu, Xin; Zhou, Hongyu; Li, Cuncheng; Ma, Shifang; Ji, Pengxia; Hou, Weikang; Wei, Ping; Zhu, Wanting; Nie, Xiaolei; Zhao, Wenyu

    2018-06-01

    The magnetic nanocomposite thermoelectric materials xFe3O4/YbAl3 ( x = 0%, 0.3%, 0.6%, 1.0%, and 1.5%) have been prepared by the combination of ultrasonic dispersion and spark plasma sintering process. The nanocomposites retain good chemical stability in the presence of the second-phase Fe3O4. The second-phase Fe3O4 magnetic nanoparticles are distributed on the interfaces and boundaries of the matrix. The x dependences of thermoelectric properties indicate that Fe3O4 magnetic nanoparticles can significantly decrease the thermal conductivity and electrical conductivity. The magnetic nanoparticles embedded in YbAl3 matrix are not only the phonon scattering centers of nanostructures, but also the electron scattering centers due to the Kondo-like effect between the magnetic moment of Fe3O4 nanoparticles and the spin of electrons. The ZT values of the composites are first increased in the x range 0%-1.0% and then decreased when x > 1.0%. The highest ZT value reaches 0.3 at 300 K for the nanocomposite with x = 1.0%. Our work demonstrates that the Fe3O4 magnetic nanoparticles can greatly increase the thermoelectric performance of heavy-fermion YbAl3 thermoelectric materials through simultaneously scattering electrons and phonons.

  18. Segmentation of low‐cost high efficiency oxide‐based thermoelectric materials

    DEFF Research Database (Denmark)

    Le, Thanh Hung; Van Nong, Ngo; Linderoth, Søren

    2015-01-01

    Thermoelectric (TE) oxide materials have attracted great interest in advanced renewable energy research owing to the fact that they consist of abundant elements, can be manufactured by low-cost processing, sustain high temperatures, be robust and provide long lifetime. However, the low conversion...... efficiency of TE oxides has been a major drawback limiting these materials to broaden applications. In this work, theoretical calculations are used to predict how segmentation of oxide and semimetal materials, utilizing the benefits of both types of materials, can provide high efficiency, high temperature...... oxide-based segmented legs. The materials for segmentation are selected by their compatibility factors and their conversion efficiency versus material cost, i.e., “efficiency ratio”. Numerical modelling results showed that conversion efficiency could reach values of more than 10% for unicouples using...

  19. First-principles study on doping and temperature dependence of thermoelectric property of Bi2S3 thermoelectric material

    International Nuclear Information System (INIS)

    Guo, Donglin; Hu, Chenguo; Zhang, Cuiling

    2013-01-01

    Graphical abstract: The direction-induced ZT is found. At ZZ direction and n = 1.47 × 10 19 cm −3 , the ZT can reach maximal value, 0.36, which is three times as much as maximal laboratorial value. This result matches well the analysis of electron effective mass. Highlights: ► Electrical transportations of Bi 2 S 3 depend on the concentration and temperature. ► The direction-induced ZT is found. ► At ZZ direction and n = 1.47 × 10 19 cm −3 , the ZT can reach maximal value, 0.36. ► The maximal ZT value is three times as much as maximal laboratorial value. ► By doping and temperature tuning, Bi 2 S 3 is a promising thermoelectric material. - Abstract: The electronic structure and thermoelectric property of Bi 2 S 3 are investigated. The electron and hole effective mass of Bi 2 S 3 is analyzed in detail, from which we find that the thermoelectric transportation varies in different directions in Bi 2 S 3 crystal. Along ac plane the higher figure of merit (ZT) could be achieved. For n-type doped Bi 2 S 3 , the optimal doping concentration is found in the range of (1.0–5.0) × 10 19 cm −3 , in which the maximal ZT reaches 0.21 at 900 K, but along ZZ direction, the maximal ZT reaches 0.36. These findings provide a new understanding of thermoelectricity-dependent structure factors and improving ZT ways. The donor concentration N increases as T increases at one bar of pressure under a suitable chemical potential μ, but above this chemical potential μ, the donor concentration N keeps a constant

  20. High-entropy alloys as high-temperature thermoelectric materials

    Energy Technology Data Exchange (ETDEWEB)

    Shafeie, Samrand [Surface and Microstructure Engineering Group, Materials and Manufacturing Technology, Chalmers University of Technology, SE-41296 Gothenburg (Sweden); Department of Chemistry and Chemical Engineering, Chalmers University of Technology, SE-41296 Gothenburg (Sweden); Guo, Sheng, E-mail: sheng.guo@chalmers.se [Surface and Microstructure Engineering Group, Materials and Manufacturing Technology, Chalmers University of Technology, SE-41296 Gothenburg (Sweden); Hu, Qiang [Institute of Applied Physics, Jiangxi Academy of Sciences, Nanchang 330029 (China); Fahlquist, Henrik [Bruker AXS Nordic AB, 17067 Solna (Sweden); Erhart, Paul [Department of Applied Physics, Chalmers University of Technology, SE-41296 Gothenburg (Sweden); Palmqvist, Anders, E-mail: anders.palmqvist@chalmers.se [Department of Chemistry and Chemical Engineering, Chalmers University of Technology, SE-41296 Gothenburg (Sweden)

    2015-11-14

    Thermoelectric (TE) generators that efficiently recycle a large portion of waste heat will be an important complementary energy technology in the future. While many efficient TE materials exist in the lower temperature region, few are efficient at high temperatures. Here, we present the high temperature properties of high-entropy alloys (HEAs), as a potential new class of high temperature TE materials. We show that their TE properties can be controlled significantly by changing the valence electron concentration (VEC) of the system with appropriate substitutional elements. Both the electrical and thermal transport properties in this system were found to decrease with a lower VEC number. Overall, the large microstructural complexity and lower average VEC in these types of alloys can potentially be used to lower both the total and the lattice thermal conductivity. These findings highlight the possibility to exploit HEAs as a new class of future high temperature TE materials.

  1. Research for Brazing Materials of High-Temperature Thermoelectric Modules with CoSb3 Thermoelectric Materials

    Science.gov (United States)

    Lee, Yu Seong; Kim, Suk Jun; Kim, Byeong Geun; Lee, Soonil; Seo, Won-Seon; Kim, Il-Ho; Choi, Soon-Mok

    2017-05-01

    Metallic glass (MG) can be a candidate for an alternative brazing material of high-temperature thermoelectric modules, since we can expect both a lower brazing temperature and a high operating temperature for the junction from the MG brazers. Another advantage of MG powders is their outstanding oxidation resistance, namely, high-temperature durability in atmosphere. We fabricated three compositions of Al-based MGs—Al-Y-Ni, Al-Y-Ni-Co, and Al-Y-Ni-Co-La—by using the melt spinning process, and their T gs were 273°C, 264°C, and 249°C, respectively. The electrical resistivity of the Al-Y-Ni MG ribbon dropped significantly after annealing at 300°C. The electrical resistivity of crystallized Al-Y-Ni reduced down to 0.03 mΩ cm, which is an order of magnitude lower than that of the amorphous one. After the MG ribbons were pulverized to sub-100 μm, the average particle size was about 400 μm.

  2. Nanostructured silicon for thermoelectric

    Science.gov (United States)

    Stranz, A.; Kähler, J.; Waag, A.; Peiner, E.

    2011-06-01

    Thermoelectric modules convert thermal energy into electrical energy and vice versa. At present bismuth telluride is the most widely commercial used material for thermoelectric energy conversion. There are many applications where bismuth telluride modules are installed, mainly for refrigeration. However, bismuth telluride as material for energy generation in large scale has some disadvantages. Its availability is limited, it is hot stable at higher temperatures (>250°C) and manufacturing cost is relatively high. An alternative material for energy conversion in the future could be silicon. The technological processing of silicon is well advanced due to the rapid development of microelectronics in recent years. Silicon is largely available and environmentally friendly. The operating temperature of silicon thermoelectric generators can be much higher than of bismuth telluride. Today silicon is rarely used as a thermoelectric material because of its high thermal conductivity. In order to use silicon as an efficient thermoelectric material, it is necessary to reduce its thermal conductivity, while maintaining high electrical conductivity and high Seebeck coefficient. This can be done by nanostructuring into arrays of pillars. Fabrication of silicon pillars using ICP-cryogenic dry etching (Inductive Coupled Plasma) will be described. Their uniform height of the pillars allows simultaneous connecting of all pillars of an array. The pillars have diameters down to 180 nm and their height was selected between 1 micron and 10 microns. Measurement of electrical resistance of single silicon pillars will be presented which is done in a scanning electron microscope (SEM) equipped with nanomanipulators. Furthermore, measurement of thermal conductivity of single pillars with different diameters using the 3ω method will be shown.

  3. Solution-processed organic thermoelectric materials exhibiting doping-concentration-dependent polarity.

    Science.gov (United States)

    Hwang, Sunbin; Potscavage, William J; Yang, Yu Seok; Park, In Seob; Matsushima, Toshinori; Adachi, Chihaya

    2016-10-26

    Recent progress in conducting polymer-based organic thermoelectric generators (OTEGs) has resulted in high performance due to high Seebeck coefficient, high electrical conductivity (σ), and low thermal conductivity obtained by chemically controlling the materials's redox levels. In addition to improving the properties of individual OTEGs to obtain high performance, the development of solution processes for the fabrication of OTEG modules is necessary to realize large thermoelectric voltage and low-cost mass production. However, the scarcity of good candidates for soluble organic n-type materials limits the use of π-leg module structures consisting of complementary elements of p- and n-type materials because of unbalanced transport coefficients that lead to power losses. In particular, the extremely low σ of n-type materials compared with that of p-type materials is a serious challenge. In this study, poly(pyridinium phenylene) (P(PymPh)) was tested as an n-type semiconductor in solution-processed OTEGs, and the carrier density was controlled by a solution-based chemical doping process using the dopant sodium naphthalenide, a well-known reductant. The electronic structures and doping mechanism of P(PymPh) were explored based on the changes in UV-Vis-IR absorption, ultraviolet photoelectron, and X-ray photoelectron spectra. By controlling the dopant concentration, we demonstrate a maximum n-type power factor of 0.81 μW m -1 K -2 with high σ, and at higher doping concentrations, a switch from n-type to p-type TE operation. This is one of the first cases of a switch in polarity just by increasing the concentration of the reductant and may open a new route for simplified fabrication of complementary organic layers.

  4. High-temperature thermoelectric behavior of lead telluride

    Indian Academy of Sciences (India)

    Usefulness of a material in thermoelectric devices is temperature specific. The central problem in thermoelectric material research is the selection of materials with high figure-of-merit in the given temperature range of operation. It is of considerable interest to know the utility range of the material, which is decided by the ...

  5. Thermoelectrical properties of the compounds ScM{sup VIII}Sb and YM{sup VIII}Sb (M{sup VIII} = Ni, Pd, Pt)

    Energy Technology Data Exchange (ETDEWEB)

    Oestreich, J; Probst, U; Richardt, F; Bucher, E [University of Konstanz, PO Box X916, D-78457 Konstanz (Germany)

    2003-02-05

    The research into new materials with good thermoelectric properties has revealed new compounds consisting of metallic elements (Bando Y, Suemitsu T, Takagi K, Tokushima H, Echizen Y, Katoh K, Umeo K, Maeda Y and Takabatake T 2000 J. Alloys Compounds 313 1-6, Ghelani N, Loo S, Chung D, Sportouch S, Nardi S, Kanatzidis M, Hogan T and Nolas G 2000 Mater. Res. Soc. 626 Z8.6.1). The half-Heusler compound ZrNiSn, in particular, shows promising thermoelectric properties and has been studied by many scientists during recent years (Uher C, Hu S, Yang J, Meisner G P and Morelli D T 1997 Proc. ICT'97: 16th Int. Conf. on Thermoelectrics pp 485-8, Romaka L P, Stadnyk Yu V, Goryn A M, Gorelenko Yu K and Skolozdra R V 1997 Proc. ICT'97: 16th Int. Conf. on Thermoelectrics pp 516-19, Hohl H, Ramirez A P, Goldmann C, Ernst G, Woelfing B and Bucher E 1998 J. Phys.: Condens. Matter 11 1697-709, Oestreich J, Kaefer W, Richardt F, Probst U and Bucher E 1999 Proc. 5th European Workshop on Thermoelectrics pp 192-5). In an effort to find new thermoelectric materials, the half-Heusler compounds of the groups ScM{sup VIII}Sb and YM{sup VIII}Sb (M{sup VIII} = Ni, Pd, Pt) were synthesized by arc melting and the thermoelectric properties were examined by standard characterization methods. Doping experiments showed that it is possible to change the electrical properties of the compounds while retaining the half-Heusler structure. Within the two groups, YPtSb showed the best thermoelectrical properties. At a temperature of 400 K the electrical conductivity of YPtSb is 748{omega}{sup -1} cm{sup -1} and the Seebeck coefficient is 116.3{mu}V K{sup -1}. The thermal conductivity at 400 K extrapolated using the Wiedemann-Franz law is 2.87 W K{sup -1} m{sup -1}. This leads to a dimensionless figure of merit of 0.14.

  6. LaBiTe3: An unusual thermoelectric material

    KAUST Repository

    Singh, Nirpendra

    2014-06-18

    Using first-principles calculations and semi-classical Boltzmann transport theory, the thermoelectric properties of LaBiTe3 are studied. The band gap and, hence, the thermoelectric response are found to be easily tailored by application of strain. Independent of the temperature, the figure of merit turns out to be maximal at a doping of about 1.6 × 1021 cm-3. At room temperature we obtain values of 0.4 and 0.5 for unstrained and moderately strained LaBiTe3, which increases to 1.1 and 1.3 at 800 K. A large spin splitting is observed in the conduction band at the T point. Therefore, LaBiTe3 merges characteristics that are interesting for thermoelectric as well as spintronic devices.

  7. LaBiTe3: An unusual thermoelectric material

    KAUST Repository

    Singh, Nirpendra; Schwingenschlö gl, Udo

    2014-01-01

    Using first-principles calculations and semi-classical Boltzmann transport theory, the thermoelectric properties of LaBiTe3 are studied. The band gap and, hence, the thermoelectric response are found to be easily tailored by application of strain. Independent of the temperature, the figure of merit turns out to be maximal at a doping of about 1.6 × 1021 cm-3. At room temperature we obtain values of 0.4 and 0.5 for unstrained and moderately strained LaBiTe3, which increases to 1.1 and 1.3 at 800 K. A large spin splitting is observed in the conduction band at the T point. Therefore, LaBiTe3 merges characteristics that are interesting for thermoelectric as well as spintronic devices.

  8. In situ neutron scattering study of nanostructured PbTe-PbS bulk thermoelectric material

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Fei [Temple University; Schmidt, Robert D [ORNL; Case, Eldon D [Michigan State University, East Lansing; An, Ke [ORNL

    2016-01-01

    Nanostructures play an important role in thermoelectric materials. Their thermal stability, such as phase change and evolution at elevated temperatures, is thus of great interest to the thermoelectric community. In this study, in situ neutron diffraction was used to examine the phase evolution of nanostructured bulk PbTe-PbS materials fabricated using hot pressing and pulsed electrical current sintering (PECS). The PbS second phase was observed in all samples in the as-pressed condition. The temperature dependent lattice parameter and phase composition data show an initial formation of PbS precipitates followed by a redissolution during heating. The redissolution process started around 570 600 K, and completed at approximately 780 K. During cooling, the PECS sample followed a reversible curve while the heating/cooling behavior of the hot pressed sample was irreversible.

  9. (Indium, Aluminum) co-doped Zinc Oxide as a Novel Material System for Quantum-Well Multilayer Thermoelectrics

    Science.gov (United States)

    Teehan, Sean

    Waste heat recovery from low efficiency industrial processes requires high performance thermoelectric materials to meet challenging requirements. The efficiency such a device is quantified by the dimensionless figure of merit ZT=S2sigmaT/kappa, where S is the Seebeck coefficient, sigma is the electrical conductivity, T is the absolute temperature and kappa is the thermal conductivity. For practical applications these devices are only cost-effective if the ZT is higher than 2. Theoretically it has been proven that by engineering nanostructures with lower dimensionality one can significantly increase ZT. A superlattice, or a system of 2-dimensional multilayer quantum wells has previously shown the potential to be used for thermoelectric structures. However, the use of conventional materials within these structures has only allowed this at low temperatures and has utilized cross-plane transport. This study focuses on both high temperature range operation and the in-plane transport properties of such structures, which benefit from both quantum confinement and an enhancement in density of states near EF. The n-type structures are fabricated by alternately sputtering barrier and well materials of Al-doped ZnO (AZO) and indium co-doped AZO, respectively. Samples investigated consist of 50 periods with targeted layer thicknesses of 10nm, which results in sufficient sampling material as well as quantum well effects. The indium doping level within the quantum well was controlled by varying the target power, and ultimately results in a 3x improvement in power factor (S 2sigma) over the parent bulk materials. The film characterization was determined by X-ray reflectometry, transmission electron microscopy, X-ray diffraction, auger electron spectroscopy, as well as other relevant techniques. In addition, process optimization was performed on material parameters such as layer thickness, interface roughness, and band-gap offset which all play a major role in determining the

  10. Ge/SiGe superlattices for nanostructured thermoelectric modules

    International Nuclear Information System (INIS)

    Chrastina, D.; Cecchi, S.; Hague, J.P.; Frigerio, J.; Samarelli, A.; Ferre–Llin, L.; Paul, D.J.; Müller, E.; Etzelstorfer, T.; Stangl, J.; Isella, G.

    2013-01-01

    Thermoelectrics are presently used in a number of applications for both turning heat into electricity and also for using electricity to produce cooling. Mature Si/SiGe and Ge/SiGe heteroepitaxial growth technology would allow highly efficient thermoelectric materials to be engineered, which would be compatible and integrable with complementary metal oxide silicon micropower circuits used in autonomous systems. A high thermoelectric figure of merit requires that electrical conductivity be maintained while thermal conductivity is reduced; thermoelectric figures of merit can be improved with respect to bulk thermoelectric materials by fabricating low-dimensional structures which enhance the density of states near the Fermi level and through phonon scattering at heterointerfaces. We have grown and characterized Ge-rich Ge/SiGe/Si superlattices for nanofabricated thermoelectric generators. Low-energy plasma-enhanced chemical vapor deposition has been used to obtain nanoscale-heterostructured material which is several microns thick. Crystal quality and strain control have been investigated by means of high resolution X-ray diffraction. High-resolution transmission electron microscopy images confirm the material and interface quality. Electrical conductivity has been characterized by the mobility spectrum technique. - Highlights: ► High-quality Ge/SiGe multiple quantum wells for thermoelectric applications ► Mobility spectra of systems featuring a large number of parallel conduction channels ► Competitive thermoelectric properties measured in single devices

  11. On one possibility for application of new thermoelectric materials based on Ag2Te

    International Nuclear Information System (INIS)

    Vassilev, Venceslav; Parvanov, Svetlin; Vachkov, Valeri

    2011-01-01

    The thermoelectric characteristics of Ag 2 Te and Ag 1,84 Cd 0,08 Te (solid solution based on Ag 2 Te) are investigated and analyzed. The main thermoelectric characteristics of the solid solution: α=118 μV/K; σ = 2230 S/cm and = 2,45.10 -2 W/(cm.K) ensure coefficient of thermoelectric efficiency z = 1,27. 10-3 K -1 (at 300 ), which increases this of the Ag 2 Te. A composition for commutation material is developed, which connects the N- and the P-branches of a single thermo element (52 wt. % In + 48 wt. % Sn) with melting temperature of 390 K. The possibility for application of the Ag 1,84 Cd 0,08 Te solid solution as N-branch of a thermo element in combination with the solid solution Bi 0,5 Sb 1,5 Te 3 (P-branch) is investigated. The thermo element guarantees values of z from 0,71.10 -3 to 1,27.10 -3 K -1 in the temperature interval 250 - 350 . The maximum z value is registered at 300 K (z = 1,27.10 -3 K -1 ). Keywords: Silver telluride, Solid solutions, Thermoelectric properties, Thermo element

  12. Systems and methods for the synthesis of high thermoelectric performance doped-SnTe materials

    Science.gov (United States)

    Ren, Zhifeng; Zhang, Qian; Chen, Gang

    2018-02-27

    A thermoelectric composition comprising tin (Sn), tellurium (Te) and at least one dopant that comprises a peak dimensionless figure of merit (ZT) of 1.1 and a Seebeck coefficient of at least 50 .mu.V/K and a method of manufacturing the thermoelectric composition. A plurality of components are disposed in a ball-milling vessel, wherein the plurality of components comprise tin (Sn), tellurium (Te), and at least one dopant such as indium (In). The components are subsequently mechanically and thermally processed, for example, by hot-pressing. In response to the mechanical-thermally processing, a thermoelectric composition is formed, wherein the thermoelectric composition comprises a dimensionless figure of merit (ZT) of the thermoelectric composition is at least 0.8, and wherein a Seebeck coefficient of the thermoelectric composition is at least 50 .mu.V/K at any temperature.

  13. Band engineering and rational design of high-performance thermoelectric materials by first-principles

    Directory of Open Access Journals (Sweden)

    Lili Xi

    2016-06-01

    Full Text Available Understanding and manipulation of the band structure are important in designing high-performance thermoelectric (TE materials. Our recent work has involved the utilization of band structure in various topics of TE research, i.e., the band convergence, the conductive network, dimensionality reduction by quantum effects, and high throughput material screening. In non-cubic chalcopyrite compounds, we revealed the relations between structural factors and band degeneracy, and a simple unity-η rule was proposed for selecting high performance diamond-like TE materials. Based on the deep understanding of the electrical and thermal transport, we identified the conductive network in filled skutterudites with the “phonon glass-electron crystal” (PGEC paradigm, and extended this concept to caged-free Cu-based diamond-like compounds. By combining the band structure calculations and the Boltzmann transport theory, we conducted a high-throughput material screening in half-Heusler (HH systems, and several promising compositions with high power factors were proposed out of a large composition collection. At last, we introduced the Rashba spin-splitting effect into thermoelectrics, and its influence on the electrical transport properties was discussed. This review demonstrated the importance of the microscopic perspectives for the optimization and design of novel TE materials.

  14. Molecular dynamics simulations of the lattice thermal conductivity of thermoelectric material CuInTe{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Wei, J. [Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan 430072 (China); Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Kowloon Tong (Hong Kong); Liu, H.J., E-mail: phlhj@whu.edu.cn [Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan 430072 (China); Cheng, L.; Zhang, J.; Jiang, P.H.; Liang, J.H.; Fan, D.D.; Shi, J. [Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan 430072 (China)

    2017-05-10

    Highlights: • A simple but effective Morse potential is constructed to accurately describe the interatomic interactions of CuInTe{sub 2}. • The lattice thermal conductivity of CuInTe{sub 2} predicted by MD agrees well with those measured experimentally, as well as those calculated from phonon BTE. • Introducing Cd impurity or Cu vacancy can effectively reduce the lattice thermal conductivity of CuInTe{sub 2} and thus further enhance its thermoelectric performance. - Abstract: The lattice thermal conductivity of thermoelectric material CuInTe{sub 2} is predicted using classical molecular dynamics simulations, where a simple but effective Morse-type interatomic potential is constructed by fitting first-principles total energy calculations. In a broad temperature range from 300 to 900 K, our simulated results agree well with those measured experimentally, as well as those obtained from phonon Boltzmann transport equation. By introducing the Cd impurity or Cu vacancy, the thermal conductivity of CuInTe{sub 2} can be effectively reduced to further enhance the thermoelectric performance of this chalcopyrite compound.

  15. Solar thermoelectric generator

    Science.gov (United States)

    Toberer, Eric S.; Baranowski, Lauryn L.; Warren, Emily L.

    2016-05-03

    Solar thermoelectric generators (STEGs) are solid state heat engines that generate electricity from concentrated sunlight. A novel detailed balance model for STEGs is provided and applied to both state-of-the-art and idealized materials. STEGs can produce electricity by using sunlight to heat one side of a thermoelectric generator. While concentrated sunlight can be used to achieve extremely high temperatures (and thus improved generator efficiency), the solar absorber also emits a significant amount of black body radiation. This emitted light is the dominant loss mechanism in these generators. In this invention, we propose a solution to this problem that eliminates virtually all of the emitted black body radiation. This enables solar thermoelectric generators to operate at higher efficiency and achieve said efficient with lower levels of optical concentration. The solution is suitable for both single and dual axis solar thermoelectric generators.

  16. Nano-Like Effects in Crystalline Thermoelectric Materials at High Temperatures

    Science.gov (United States)

    Korzhuev, M. A.; Katin, I. V.

    2013-05-01

    The mechanisms of improving the figure of merit Z and power parameter W of thermoelectric materials (TEMs) in the transitions λph→a and λe→a are considered (Here λph and λe are the mean free path of the phonons and electrons in the sample, and a is the inter atomic distance). It is shown that the same mechanisms are responsible for the growth of Z and W crystalline TEMs at high temperatures.

  17. Estimating Seebeck Coefficient of a p-Type High Temperature Thermoelectric Material Using Bee Algorithm Multi-layer Perception

    Science.gov (United States)

    Uysal, Fatih; Kilinc, Enes; Kurt, Huseyin; Celik, Erdal; Dugenci, Muharrem; Sagiroglu, Selami

    2017-08-01

    Thermoelectric generators (TEGs) convert heat into electrical energy. These energy-conversion systems do not involve any moving parts and are made of thermoelectric (TE) elements connected electrically in a series and thermally in parallel; however, they are currently not suitable for use in regular operations due to their low efficiency levels. In order to produce high-efficiency TEGs, there is a need for highly heat-resistant thermoelectric materials (TEMs) with an improved figure of merit ( ZT). Production and test methods used for TEMs today are highly expensive. This study attempts to estimate the Seebeck coefficient of TEMs by using the values of existing materials in the literature. The estimation is made within an artificial neural network (ANN) based on the amount of doping and production methods. Results of the estimations show that the Seebeck coefficient can approximate the real values with an average accuracy of 94.4%. In addition, ANN has detected that any change in production methods is followed by a change in the Seebeck coefficient.

  18. Design, modeling and utilization of thermoelectrical materials and devices in energy systems

    DEFF Research Database (Denmark)

    Chen, Min

    Thermoelectric generators can convert waste heat that abounds in modern societies into electricity in an environmentally-friendly and reliable manner, and many applications of thermoelectric devices can be envisaged. The research of this PhD dissertation focuses thermoelectric generator modeling...... at a device level as well as its applications in energy systems. The purpose is to introduce the use of thermoelectric generator into energy systems, and to indicate the impact of implementing thermoelectric generator on the design and operation of energy systems. For this purpose, this dissertation produces...... numerical models as versatile simulation tools to identify speci c optimum design criteria for thermoelectric generators used in various associated thermal and electrical systems, so that the generation performance can be improved due to the optimum system design....

  19. Introduction to thermoelectricity

    CERN Document Server

    Goldsmid, H Julian

    2016-01-01

    This book is a comprehensive introduction to all aspects of thermoelectric energy conversion. It covers both theory and practice. The book is timely as it refers to the many improvements that have come about in the last few years through the use of nanostructures. The concept of semiconductor thermoelements led to major advances during the second half of the twentieth century, making Peltier refrigeration a widely used technique. The latest materials herald thermoelectric generation as the preferred technique for exploiting low-grade heat. The book shows how progress has been made by increasing the thermal resistivity of the lattice until it is almost as large as it is for glass. It points the way towards the attainment of similar improvements in the electronic parameters. It does not neglect practical considerations, such as the desirability of making thermocouples from inexpensive and environmentally acceptable materials. The second edition was extended to also include recent advances in thermoelectric ener...

  20. NANOSTRUCTURING AS A WAY FOR THERMOELECTRIC EFFICIENCY IMPROVEMENT

    Directory of Open Access Journals (Sweden)

    L. V. Bochkov

    2014-07-01

    Full Text Available The urgency of thermoelectric energy conversion is proved. Perspectives of nanostructures usage as thermoelectric materials are shown. The authors have systematized and generalized the methods and investigation results of bulk nanostructure thermoelectrics based on Bi-Sb-Te solid solutions. Ways of nanoparticles fabrication and their subsequent sintering into a bulk sample, results of structure study of the received materials are shown by methods of electronic microscopy and X-ray spectroscopy, results of mechanical properties investigation. Methods of manufacturing suggested with the authors’ participation and properties of thermoelectric nanocomposites, fabricated with addition of fullerene, thermally split graphite, graphene and molybdenum disulphide are discussed. Methods for prevention of recrystallization, measurement methods of thermoelectric properties of studied nanothermoelectrics are considered, including electric and thermal conductivities, thermoemf and the figure of merit. Factors that influence on thermoelectric figure of merit, including the tunneling of carriers through interfaces between nanograins, the additional phonon scattering on nanograin borders and the energy filtration of carriers through barriers have been theoretically investigated. Mechanisms and ways for improvement of the figure of merit are determined. Experimental confirmation for thermoelectric figure of merit increase is received. Physical mechanisms of thermoelectric figure of merit increase are shown by perceptivity of nanostructures utilization. The growth of thermoelectric figure of merit means an expansion of areas for rational application of thermoelectric energy generation and thermoelectric cooling.

  1. Lead telluride with increased mechanical stability for cylindrical thermoelectric generators

    International Nuclear Information System (INIS)

    Schmitz, Andreas

    2013-01-01

    The aim of this work is to improve the mechanical stability of lead telluride (PbTe), trying to vary its mechanical properties independently from its thermoelectric properties. Thus the influence of material preparation as well as different dopants on the mechanical and thermoelectric properties of lead telluride is being analysed. When using appropriately set process parameters, milling and sintering of lead telluride increases the material's hardness. With sintering temperatures exceeding 300 C stable material of high relative density can be achieved. Milling lead telluride generates lattice defects leading to a reduction of the material's charge carrier density. These defects can be reduced by increased sintering temperatures. Contamination of the powder due to the milling process leads to bloating during thermal cycling and thus reduced density of the sintered material. In addition to that, evaporation of tellurium at elevated temperatures causes instability of the material's thermoelectric properties. Based on the experimental results obtained in this work, the best thermoelectric and mechanical properties can be obtained by sintering coarse powders at around 400 C. Within this work a concept was developed to vary the mechanical properties of lead telluride via synthesis of PbTe with electrically nondoping elements, which thus may keep the thermoelectric properties unchanged. Therefore, the mechanical and thermoelectric properties of Pb 1-x Ca x Te were investigated. Doping pure PbTe with calcium causes a significant increase of the material's hardness while only slightly decreasing the charge carrier density and thus keeping the thermoelectric properties apart from a slight reduction of the electrical conductivity nearly unchanged. The abovementioned concept is proven using sodium doped lead telluride, as it is used for thermoelectric generators: The additional doping with calcium again increases the material's hardness while its thermoelectric properties

  2. The thermoelectric figure of merit of poor thermal conductors

    International Nuclear Information System (INIS)

    Dixon, A.J.

    1977-01-01

    Calculations are given to show that for low thermal conductivity materials the radiation losses at even moderate temperatures preclude the use of the Harman technique for measuring the thermoelectric figure of merit. Measurements on liquid Tl 66 Se 34 , which has suitable thermoelectric properties, confirm this. (author)

  3. Synthesis and Characterization of Thermoelectric Oxides at Macro- and Nano-scales

    Science.gov (United States)

    Ma, Feiyue

    Thermoelectric materials can directly convert a temperature difference into electrical voltage and vice versa. Due to this unique property, thermoelectric materials are widely used in industry and scientific laboratories for temperature sensing and thermal management applications. Waste heat harvesting, another potential application of thermoelectric materials, has long been limited by the low conversion efficiency of the materials. Potential high temperature applications, such as power plant waste heat harvesting and combustion engine exhaust heat recovery, make thermoelectric oxides a very promising class of thermoelectric materials. In this thesis, the synthesis and characterization of thermoelectric oxide materials are explored. In the first part of this thesis, the measurement methodologies and instrumentation processes employed to investigate different thermoelectric properties, such as the Seebeck coefficient and carrier concentration at the bulk scale and the thermal conductivity at the nanoscale, are detailed. Existing scientific and engineering challenges associated with these measurements are also reviewed. To overcome such problems, original parts and methodologies have been designed. Three fully functional systems were ultimately developed for the characterization of macroscale thermoelectric properties as well as localized thermal conductivity. In the second part of the thesis, the synthesis of NaxCo 2O4, a thermoelectric oxide material, is discussed. Modification of both composition and structure were carried out so as to optimize the thermoelectric performance of NaxCo2O4. Nanostructuring methods, such as ball milling, electrospinning, auto-combustion synthesis, and core-shell structure fabrication, have been developed to refine the grain size of NaxCo2O4 in order to reduce its thermal conductivity. However, the structure of the nanostructured materials is very unstable at high temperature and limited improvement on thermoelectric performance is

  4. Strain-induced bi-thermoelectricity in tapered carbon nanotubes

    Science.gov (United States)

    Algharagholy, L. A. A.; Pope, T.; Lambert, C. J.

    2018-03-01

    We show that carbon-based nanostructured materials are a novel testbed for controlling thermoelectricity and have the potential to underpin the development of new cost-effective environmentally-friendly thermoelectric materials. In single-molecule junctions, it is known that transport resonances associated with the discrete molecular levels play a key role in the thermoelectric performance, but such resonances have not been exploited in carbon nanotubes (CNTs). Here we study junctions formed from tapered CNTs and demonstrate that such structures possess transport resonances near the Fermi level, whose energetic location can be varied by applying strain, resulting in an ability to tune the sign of their Seebeck coefficient. These results reveal that tapered CNTs form a new class of bi-thermoelectric materials, exhibiting both positive and negative thermopower. This ability to change the sign of the Seebeck coefficient allows the thermovoltage in carbon-based thermoelectric devices to be boosted by placing CNTs with alternating-sign Seebeck coefficients in tandem.

  5. Bulk Material Based Thermoelectric Energy Harvesting for Wireless Sensor Applications

    International Nuclear Information System (INIS)

    Wang, W S; Magnin, W; Wang, N; Hayes, M; O'Flynn, B; O'Mathuna, C

    2011-01-01

    The trend towards smart building and modern manufacturing demands ubiquitous sensing in the foreseeable future. Self-powered Wireless sensor networks (WSNs) are essential for such applications. This paper describes bulk material based thermoelectric generator (TEG) design and implementation for WSN. A 20cm 2 Bi 0.5 Sb 1.5 Te 3 based TEG was created with optimized configuration and generates 2.7mW in typical condition. A novel load matching method is used to maximize the power output. The implemented power management module delivers 651μW to WSN in 50 deg. C. With average power consumption of Tyndall WSN measured at 72μW, feasibility of utilizing bulk material TEG to power WSN is demonstrated.

  6. Bi2O2Se nanosheet: An excellent high-temperature n-type thermoelectric material

    Science.gov (United States)

    Yu, Jiabing; Sun, Qiang

    2018-01-01

    Motivated by the recent synthesis of an ultrathin film of layered Bi2O2Se [Wu et al., Nat. Nanotechnol. 12, 530 (2017); Wu et al., Nano Lett. 17, 3021 (2017)], we have systematically studied the thermoelectric properties of a Bi2O2Se nanosheet using first principles density functional theory combined with semiclassical Boltzmann transport theory. The calculated results indicate that the Bi2O2Se nanosheet exhibits a figure of merit (ZT) of 3.35 for optimal n-type doping at 800 K, which is much larger than the ZT value of 2.6 at 923 K in SnSe known as the most efficient thermoelectric material [Zhao et al., Nature 508, 373 (2014)]. Equally important, the high ZT in the n-type doped Bi2O2Se nanosheet highlights the efficiency of the reduced dimension on improving thermoelectric performance as compared with strain engineering by which the ZT of n-type doped bulk Bi2O2Se cannot be effectively enhanced.

  7. Terahertz and infrared transmission of an organic/inorganic hybrid thermoelectric material

    International Nuclear Information System (INIS)

    Heyman, J. N.; Alebachew, B. A.; Kaminski, Z. S.; Nguyen, M. D.; Coates, N. E.; Urban, J. J.

    2014-01-01

    We report terahertz and infrared transmission measurements of a high-performance thermoelectric material containing tellurium nanowires in a conducting polymer poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) matrix. The DC electrical conductivity of the hybrid material (41 S/cm) is approximately one hundred times that of pure PEDOT:PSS and more than 400 times that of a film of pure tellurium nanowires, while the terahertz-frequency (THz) conductivity of PEDOT:PSS and the hybrid material are comparable at f ∼ 2THz. A frequency-dependent conductivity model indicates that the increased DC conductivity of the hybrid material results from an increase in the DC charge mobility rather than in the free charge density. We suggest that the increased DC conductivity of the hybrid material results from an increase in linkage between PEDOT domains by the tellurium nanowires

  8. Terahertz and infrared transmission of an organic/inorganic hybrid thermoelectric material

    Energy Technology Data Exchange (ETDEWEB)

    Heyman, J. N., E-mail: heyman@macalester.edu; Alebachew, B. A.; Kaminski, Z. S.; Nguyen, M. D. [Physics Department, Macalester College, St. Paul, Minnesota 55105 (United States); Coates, N. E.; Urban, J. J. [The Molecular Foundry, Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

    2014-04-07

    We report terahertz and infrared transmission measurements of a high-performance thermoelectric material containing tellurium nanowires in a conducting polymer poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) matrix. The DC electrical conductivity of the hybrid material (41 S/cm) is approximately one hundred times that of pure PEDOT:PSS and more than 400 times that of a film of pure tellurium nanowires, while the terahertz-frequency (THz) conductivity of PEDOT:PSS and the hybrid material are comparable at f ∼ 2THz. A frequency-dependent conductivity model indicates that the increased DC conductivity of the hybrid material results from an increase in the DC charge mobility rather than in the free charge density. We suggest that the increased DC conductivity of the hybrid material results from an increase in linkage between PEDOT domains by the tellurium nanowires.

  9. Compatibility of Segments of Thermoelectric Generators

    Science.gov (United States)

    Snyder, G. Jeffrey; Ursell, Tristan

    2009-01-01

    A method of calculating (usually for the purpose of maximizing) the power-conversion efficiency of a segmented thermoelectric generator is based on equations derived from the fundamental equations of thermoelectricity. Because it is directly traceable to first principles, the method provides physical explanations in addition to predictions of phenomena involved in segmentation. In comparison with the finite-element method used heretofore to predict (without being able to explain) the behavior of a segmented thermoelectric generator, this method is much simpler to implement in practice: in particular, the efficiency of a segmented thermoelectric generator can be estimated by evaluating equations using only hand-held calculator with this method. In addition, the method provides for determination of cascading ratios. The concept of cascading is illustrated in the figure and the definition of the cascading ratio is defined in the figure caption. An important aspect of the method is its approach to the issue of compatibility among segments, in combination with introduction of the concept of compatibility within a segment. Prior approaches involved the use of only averaged material properties. Two materials in direct contact could be examined for compatibility with each other, but there was no general framework for analysis of compatibility. The present method establishes such a framework. The mathematical derivation of the method begins with the definition of reduced efficiency of a thermoelectric generator as the ratio between (1) its thermal-to-electric power-conversion efficiency and (2) its Carnot efficiency (the maximum efficiency theoretically attainable, given its hot- and cold-side temperatures). The derivation involves calculation of the reduced efficiency of a model thermoelectric generator for which the hot-side temperature is only infinitesimally greater than the cold-side temperature. The derivation includes consideration of the ratio (u) between the

  10. Transport and first-principles study of novel thermoelectric materials

    Science.gov (United States)

    Chi, Hang

    Thermoelectric materials can recover waste industrial heat and convert it to electricity as well as provide efficient local cooling of electronic devices. The efficiency of such environmentally responsible and exceptionally reliable solid state energy conversion is determined by the dimensionless figure-of-merit ZT = alpha2 sigmaT/kappa, where alpha is the Seebeck coefficient, sigma is the electrical conductivity, kappa is the thermal conductivity, and T is the absolute temperature. The goal of the thesis is to (i) illustrate the physics to achieve high ZT of advanced thermoelectric materials and (ii) explore fundamental structure and transport properties in novel condensed matter systems, via an approach combining comprehensive experimental techniques and state-of-the-art first-principles simulation methods. Thermo-galvanomagnetic transport coefficients are derived from Onsager's reciprocal relations and evaluated via solving Boltzmann transport equation using Fermi-Dirac statistics, under the relaxation time approximation. Such understanding provides insights on enhancing ZT through two physically intuitive and very effective routes: (i) improving power factor PF = alpha2sigma; and (ii) reducing thermal conductivity kappa, as demonstrated in the cases of Mg2Si1-xSnx solid solution and Ge/Te double substituted skutterudites CoSb3(1-x)Ge1.5x Te1.5x, respectively. Motivated by recent theoretical predictions of enhanced thermoelectric performance in highly mismatched alloys, ZnTe:N molecular beam epitaxy (MBE) films deposited on GaAs (100) substrates are carefully examined, which leads to a surprising discovery of significant phonon-drag thermopower (reaching 1-2 mV/K-1) at ~13 K. Further systematic study in Bi2Te3 MBE thin films grown on sapphire (0001) and/or BaF2 (111) substrates, reveal that the peak of phonon drag can be tuned by the choice of substrates with different Debye temperatures. Moreover, the detailed transport and structure studies of Bi2-xTl xTe3

  11. Thermoelectric properties of low-dimensional clathrates from first principles

    Science.gov (United States)

    Kasinathan, Deepa; Rosner, Helge

    2011-03-01

    Type-I inorganic clathrates are host-guest structures with the guest atoms trapped in the framework of the host structure. From a thermoelectric point of view, they are interesting because they are semiconductors with adjustable bandgaps. Investigations in the past decade have shown that type-I clathrates X8 Ga 16 Ge 30 (X = Ba, Sr, Eu) may have the unusual property of ``phonon glass-electron crystal'' for good thermoelectric materials. Among the known clathrates, Ba 8 Ga 16 Ge 30 has the highest figure of merit (ZT~1). To enable a more widespread usage of thermoelectric technology power generation and heating/cooling applications, ZT of at least 2-3 is required. Two different research approaches have been proposed for developing next generation thermoelectric materials: one investigating new families of advanced bulk materials, and the other studying low-dimensional materials. In our work, we concentrate on understanding the thermoelectric properties of the nanostructured Ba-based clathrates. We use semi-classical Boltzmann transport equations to calculate the various thermoelectric properties as a function of reduced dimensions. We observe that there exists a delicate balance between the electrical conductivity and the electronic part of the thermal conductivity in reduced dimensions. Insights from these results can directly be used to control particle size in nanostructuring experiments.

  12. High thermoelectric performance of graphite nanofibers.

    Science.gov (United States)

    Tran, Van-Truong; Saint-Martin, Jérôme; Dollfus, Philippe; Volz, Sebastian

    2018-02-22

    Graphite nanofibers (GNFs) have been demonstrated to be a promising material for hydrogen storage and heat management in electronic devices. Here, by means of first-principles and transport simulations, we show that GNFs can also be an excellent material for thermoelectric applications thanks to the interlayer weak van der Waals interaction that induces low thermal conductance and a step-like shape in the electronic transmission with mini-gaps, which are necessary ingredients to achieve high thermoelectric performance. This study unveils that the platelet form of GNFs in which graphite layers are perpendicular to the fiber axis can exhibit outstanding thermoelectric properties with a figure of merit ZT reaching 3.55 in a 0.5 nm diameter fiber and 1.1 in a 1.1 nm diameter one. Interestingly, by introducing 14 C isotope doping, ZT can even be enhanced up to more than 5, and more than 8 if we include the effect of finite phonon mean free path, which demonstrates the amazing thermoelectric potential of GNFs.

  13. Research Update: Phonon engineering of nanocrystalline silicon thermoelectrics

    Directory of Open Access Journals (Sweden)

    Junichiro Shiomi

    2016-10-01

    Full Text Available Nanocrystalline silicon thermoelectrics can be a solution to improve the cost-effectiveness of thermoelectric technology from both material and integration viewpoints. While their figure-of-merit is still developing, recent advances in theoretical/numerical calculations, property measurements, and structural synthesis/fabrication have opened up possibilities to develop the materials based on fundamental physics of phonon transport. Here, this is demonstrated by reviewing a series of works on nanocrystalline silicon materials using calculations of multiscale phonon transport, measurements of interfacial heat conduction, and synthesis from nanoparticles. Integration of these approaches allows us to engineer phonon transport to improve the thermoelectric performance by introducing local silicon-oxide structures.

  14. Evaluation of Thermoelectric Performance and Durability of Functionalized Skutterudite Legs

    Science.gov (United States)

    Skomedal, Gunstein; Kristiansen, Nils R.; Sottong, Reinhard; Middleton, Hugh

    2017-04-01

    Thermoelectric generators are a promising technology for waste heat recovery. As new materials and devices enter a market penetration stage, it is of interest to employ fast and efficient measurement methods to evaluate the long-term stability of thermoelectric materials in combination with metallization and coating (functionalized thermoelectric legs). We have investigated a method for measuring several thermoelectric legs simultaneously. The legs are put under a common temperature gradient, and the electrical characteristics of each leg are measured individually during thermal cycling. Using this method, one can test different types of metallization and coating applied to skutterudite thermoelectric legs and look at the relative changes over time. Postcharacterization of these initial tests with skutterudite legs using a potential Seebeck microprobe and an electron microscope showed that oxidation and interlayer diffusion are the main reasons for the gradual increase in internal resistance and the decrease in open-circuit voltage. Although we only tested skutterudite material in this work, the method is fully capable of testing all kinds of material, metallization, and coating. It is thus a promising method for studying the relationship between failure modes and mechanisms of functionalized thermoelectric legs.

  15. Protection and thermal management of thermoelectric generator system using phase change materials: An experimental investigation

    DEFF Research Database (Denmark)

    Ahmadi Atouei, Saeed; Rezaniakolaei, Alireza; Ranjbar, A.A.

    2018-01-01

    In most thermoelectric systems the thermal boundary conditions are transient, and thermal manage-ment of the system is critical to improve electrical performance of the system. In this study, effect of using phase change materials (PCM) to control the hot and cold side temperatures...

  16. Alkaline earth lead and tin compounds Ae2Pb, Ae2Sn, Ae = Ca, Sr, Ba, as thermoelectric materials

    Science.gov (United States)

    Parker, David; Singh, David J

    2013-01-01

    We present a detailed theoretical study of three alkaline earth compounds Ca2Pb, Sr2Pb and Ba2Pb, which have undergone little previous study, calculating electronic band structures and Boltzmann transport and bulk moduli using density functional theory. We also study the corresponding tin compounds Ca2Sn, Sr2Sn and Ba2Sn. We find that these are all narrow band gap semiconductors with an electronic structure favorable for thermoelectric performance, with substantial thermopowers for the lead compounds at temperature ranges from 300 to 800 K. For the lead compounds, we further find very low calculated bulk moduli—roughly half of the values for the lead chalcogenides, suggestive of soft phonons and hence low lattice thermal conductivity. All these facts indicate that these materials merit experimental investigation as potential high performance thermoelectrics. We find good potential for thermoelectric performance in the environmentally friendly stannide materials, particularly at high temperature. PMID:27877610

  17. Alkaline earth lead and tin compounds Ae2Pb, Ae2Sn, Ae = Ca, Sr, Ba, as thermoelectric materials

    Directory of Open Access Journals (Sweden)

    David Parker and David J Singh

    2013-01-01

    Full Text Available We present a detailed theoretical study of three alkaline earth compounds Ca2Pb, Sr2Pb and Ba2Pb, which have undergone little previous study, calculating electronic band structures and Boltzmann transport and bulk moduli using density functional theory. We also study the corresponding tin compounds Ca2Sn, Sr2Sn and Ba2Sn. We find that these are all narrow band gap semiconductors with an electronic structure favorable for thermoelectric performance, with substantial thermopowers for the lead compounds at temperature ranges from 300 to 800 K. For the lead compounds, we further find very low calculated bulk moduli—roughly half of the values for the lead chalcogenides, suggestive of soft phonons and hence low lattice thermal conductivity. All these facts indicate that these materials merit experimental investigation as potential high performance thermoelectrics. We find good potential for thermoelectric performance in the environmentally friendly stannide materials, particularly at high temperature.

  18. Two-Dimensional Tellurene as Excellent Thermoelectric Material

    KAUST Repository

    Sharma, Sitansh

    2018-04-20

    We study the thermoelectric properties of two-dimensional tellurene by first-principles calculations and semiclassical Boltzmann transport theory. The HSE06 hybrid functional results in a moderate direct band gap of 1.48 eV at the Γ point. A high room temperature Seebeck coefficient (Sxx = 0.38 mV/K, Syy = 0.36 mV/K) is combined with anisotropic lattice thermal conductivity (κxxl = 0.43 W/m K, κyyl = 1.29 W/m K). Phonon band structures demonstrate a key role of optical phonons in the record low thermal conductivity that leads to excellent thermoelectric performance of tellurene. At room temperature and moderate hole doping of 1.2 × 10–11 cm–2, for example, a figure of merit of ZTxx = 0.8 is achieved.

  19. Performance and stress analysis of oxide thermoelectric module architecture designed for maximum power output

    DEFF Research Database (Denmark)

    Wijesekara, Waruna; Rosendahl, Lasse; Wu, NingYu

    Oxide thermoelectric materials are promising candidates for energy harvesting from mid to high temperature heat sources. In this work, the oxide thermoelectric materials and the final design of the high temperature thermoelectric module were developed. Also, prototypes of oxide thermoelectric...... of real thermoelectric uni-couples, the three-dimensional governing equations for the coupled heat transfer and thermoelectric effects were developed. Finite element simulations of this system were done using the COMSOL Multiphysics solver. Prototypes of the models were developed and the analytical...... generator were built for high temperature applications. This paper specifically discusses the thermoelectric module design and the prototype validations of the design. Here p type calcium cobalt oxide and n type aluminum doped ZnO were developed as the oxide thermoelectric materials. Hot side and cold side...

  20. All dispenser printed flexible 3D structured thermoelectric generators

    Science.gov (United States)

    Cao, Z.; Shi, J. J.; Torah, R. N.; Tudor, M. J.; Beeby, S. P.

    2015-12-01

    This work presents a vertically fabricated 3D thermoelectric generator (TEG) by dispenser printing on flexible polyimide substrate. This direct-write technology only involves printing of electrodes, thermoelectric active materials and structure material, which needs no masks to transfer the patterns onto the substrate. The dimension for single thermoelectric element is 2 mm × 2 mm × 0.5 mm while the distance between adjacent cubes is 1.2 mm. The polymer structure layer was used to support the electrodes which are printed to connect the top ends of the thermoelectric material and ensure the flexibility as well. The advantages and the limitations of the dispenser printed 3D TEGs will also be evaluated in this paper. The proposed method is potential to be a low-cost and scalable fabrication solution for TEGs.

  1. High efficiency semimetal/semiconductor nanocomposite thermoelectric materials

    International Nuclear Information System (INIS)

    Zide, J. M. O.; Bahk, J.-H.; Zeng, G.; Bowers, J. E.; Singh, R.; Zebarjadi, M.; Bian, Z. X.; Shakouri, A.; Lu, H.; Gossard, A. C.; Feser, J. P.; Xu, D.; Singer, S. L.; Majumdar, A.

    2010-01-01

    Rare-earth impurities in III-V semiconductors are known to self-assemble into semimetallic nanoparticles which have been shown to reduce lattice thermal conductivity without harming electronic properties. Here, we show that adjusting the band alignment between ErAs and In 0.53 Ga 0.47-X Al X As allows energy-dependent scattering of carriers that can be used to increase thermoelectric power factor. Films of various Al concentrations were grown by molecular beam epitaxy, and thermoelectric properties were characterized. We observe concurrent increases in electrical conductivity and Seebeck coefficient with increasing temperatures, demonstrating energy-dependent scattering. We report the first simultaneous power factor enhancement and thermal conductivity reduction in a nanoparticle-based system, resulting in a high figure of merit, ZT=1.33 at 800 K.

  2. Investigation of mesoporous structures for thermoelectric applications

    International Nuclear Information System (INIS)

    Cojocaru, A.; Carstensen, J.; Foell, H.; Boor, J.; Schmidt, V.

    2011-01-01

    Mesoporous silicon is an attractive material for thermoelectric application. For pore wall thicknesses around <100 nm, phonons can not penetrate the porous layer while electrons still can, due to there smaller mean free path length. The resulting good electrical and bad thermal conductivity is a premise for efficient thermoelectric devices. This paper presents results regarding homogeneity, high porosity, and optimal pore wall thicknesses for porous silicon based thermoelectric devices.

  3. Processing and nanostructure influences on mechanical properties of thermoelectric materials

    Science.gov (United States)

    Schmidt, Robert David

    Thermoelectric (TE) materials are materials that can generate an electric current from a thermal gradient, with possible service in recovery of waste heat such as engine exhaust. Significant progress has been made in improving TE conversion efficiency, typically reported according to the figure of merit, ZT, with several recent papers publishing ZT values above 2. Furthermore, cost reductions may be made by the use of lower cost elements such as Mg, Si, Sn, Pb, Se and S in TE materials, while achieving ZT values between 1.3 and 1.8. To be used in a device, the thermoelectric material must be able to withstand the applied thermal and mechanical forces without failure. However, these materials are brittle, with low fracture toughness typically less than 1.5 MPa-m1/2, and often less than 0.5 MPa-m1/2. For comparison, window glass is approximately 0.75 MPa-m1/2. They have been optimized with nanoprecipitates, nanoparticles, doping, alterations in stoichiometry, powder processing and other techniques, all of which may alter the mechanical properties. In this study, the effect of SiC nanoparticle additions in Mg2Si, SnTe and Ag nanoparticle additions in the skutterudite Ba0.3Co 4Sb12 on the elastic moduli, hardness and fracture toughness are measured. Large changes (˜20%) in the elastic moduli in SnTe 1+x as a function of x at 0 and 0.016 are shown. The effect on mechanical properties of doping and precipitates of CdS or ZnS in a PbS or PbSe matrix have been reported. Changes in sintering behavior of the skutterudite with the Ag nanoparticle additions were explored. Possible liquid phase sintering, with associated benefits in lower processing temperature, faster densification and lower cost, has been shown. A technique has been proposed for determining additional liquid phase sintering aids in other TE materials. The effects of porosity, grain size, powder processing method, and sintering method were explored with YbAl3 and Ba0.3Co4Sb 12, with the porosity dependence of

  4. Thermoelectric Performance of Na-Doped GeSe

    NARCIS (Netherlands)

    Shaabani, Laaya; Aminorroaya-Yamini, Sima; Byrnes, Jacob; Akbar Nezhad, Ali; Blake, Graeme R

    2017-01-01

    Recently, hole-doped GeSe materials have been predicted to exhibit extraordinary thermoelectric performance owing largely to extremely low thermal conductivity. However, experimental research on the thermoelectric properties of GeSe has received less attention. Here, we have synthesized

  5. The system of thermoelectric air conditioning based on permeable thermoelements

    Directory of Open Access Journals (Sweden)

    Cherkez R. G.

    2009-04-01

    Full Text Available There is thermoelectric air conditioner unit on the basis of permeable cooling thermoelements presented. In thermoelectric air conditioner unit the thermoelectric effects and the Joule–Thomson effect have been used for the air stream cooling. There have been described the method of temperature distribution analysis, the determinations of energy conversion power characteristics and design style of permeable thermoelement with maximum coefficient of performance described. The results of computer analysis concerning the application of the thermoelement legs material on the basis of Bi2Te3 have shown the possibility of coefficient of performance increase by a factor of 1,6—1,7 as compared with conventional thermoelectric systems.

  6. Thermoelectric SQUID method for the detection of segregations

    Science.gov (United States)

    Hinken, Johann H.; Tavrin, Yury

    2000-05-01

    Aero engine turbine discs are most critical parts. Material inhomogeneities can cause disc fractures during the flight with fatal air disasters. Nondestructive testing (NDT) of the discs in various machining steps is necessary and performed as well as possible. Conventional NDT methods, however, like eddy current testing and ultrasonic testing have unacceptable limits. For example, subsurface segregations often cannot be detected directly but only indirectly in such cases when cracks already have developed from them. This may be too late. A new NDT method, which we call the Thermoelectric SQUID Method, has been developed. It allows for the detection of metallic inclusions within non-ferromagnetic metallic base material. This paper describes the results of a feasibility study on aero engine turbine discs made from Inconel® 718. These contained segregations that had been detected before by anodic etching. With the Thermoelectric SQUID Method, these segregations were detected again, and further segregations below the surfaces have been found, which had not been detected before. For this new NDT method the disc material is quasi-transparent. The Thermoelectric SQUID Method is also useful to detect distributed and localized inhomogeneities in pure metals like niobium sheets for particle accelerators.

  7. Two-Dimensional Tellurene as Excellent Thermoelectric Material

    KAUST Repository

    Sharma, Sitansh; Singh, Nirpendra; Schwingenschlö gl, Udo

    2018-01-01

    We study the thermoelectric properties of two-dimensional tellurene by first-principles calculations and semiclassical Boltzmann transport theory. The HSE06 hybrid functional results in a moderate direct band gap of 1.48 eV at the Γ point. A high

  8. Electronic structure and high thermoelectric properties of a new material Ba{sub 3}Cu{sub 20}Te{sub 13}

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Gui, E-mail: kuiziyang@126.com [College of Physics and Electrical Engineering, Anyang Normal University, Anyang, Henan, 455000 (China); Wu, Jinghe [Department of Physics and Electronic Engineering, Henan Institute of Education, Zhengzhou, 450046 (China); Zhang, Jing; Ma, Dongwei [College of Physics and Electrical Engineering, Anyang Normal University, Anyang, Henan, 455000 (China)

    2016-09-05

    The electronic structure and high thermoelectric properties of Ba{sub 3}Cu{sub 20}Te{sub 13} are studied using first principles calculations and the semiclassical Boltzmann theory. The coexistence of ionic and covalent bonding in Ba{sub 3}Cu{sub 20}Te{sub 13} indicates that it is a Zintl phase compound. The calculated band structure shows that the compound is a semiconductor with an indirect band gap ∼0.45 eV, which is an appropriate band for the high thermoelectric performance. The transport calculations based on the electronic structure indicate that it exhibits relatively large Seebeck coefficients, high electrical conductivities, and high power factor. For Ba{sub 3}Cu{sub 20}Te{sub 13}, the n-type doping may achieve a higher thermoelectric performance than that of p-type doping. It is worth noting that the thermoelectric parameters of Ba{sub 3}Cu{sub 20}Te{sub 13} are comparable or larger than that of Ca{sub 5}Al{sub 2}Sb{sub 6}, a typical Zintl compound representative with high thermoelectric performance. - Highlights: • The electronic structure and thermoelectric(TE) properties are firstly studied. • The heavy and light bands near the Fermi level benefit TE properties. • The comparison indicates Ba{sub 3}Cu{sub 20}Te{sub 13} is a potential high TE material.

  9. Intrinsically High Thermoelectric Performance in AgInSe2 n-Type Diamond-Like Compounds.

    Science.gov (United States)

    Qiu, Pengfei; Qin, Yuting; Zhang, Qihao; Li, Ruoxi; Yang, Jiong; Song, Qingfeng; Tang, Yunshan; Bai, Shengqiang; Shi, Xun; Chen, Lidong

    2018-03-01

    Diamond-like compounds are a promising class of thermoelectric materials, very suitable for real applications. However, almost all high-performance diamond-like thermoelectric materials are p-type semiconductors. The lack of high-performance n-type diamond-like thermoelectric materials greatly restricts the fabrication of diamond-like material-based modules and their real applications. In this work, it is revealed that n-type AgInSe 2 diamond-like compound has intrinsically high thermoelectric performance with a figure of merit ( zT ) of 1.1 at 900 K, comparable to the best p-type diamond-like thermoelectric materials reported before. Such high zT is mainly due to the ultralow lattice thermal conductivity, which is fundamentally limited by the low-frequency Ag-Se "cluster vibrations," as confirmed by ab initio lattice dynamic calculations. Doping Cd at Ag sites significantly improves the thermoelectric performance in the low and medium temperature ranges. By using such high-performance n-type AgInSe 2 -based compounds, the diamond-like thermoelectric module has been fabricated for the first time. An output power of 0.06 W under a temperature difference of 520 K between the two ends of the module is obtained. This work opens a new window for the applications using the diamond-like thermoelectric materials.

  10. Combustion synthesis: A new approach for preparation of thermoelectric zinc antimonide compounds

    Energy Technology Data Exchange (ETDEWEB)

    Rouessac, F., E-mail: Florence.Rouessac@univ-montp2.fr [Institut Charles Gerhardt Montpellier, UMR 5253 CNRS-UM2-ENSCM-UM1, C2M Universite Montpellier 2, CC 1504 Place Eugene Bataillon, 34095 Montpellier Cedex 5 (France); Ayral, R.-M. [Institut Charles Gerhardt Montpellier, UMR 5253 CNRS-UM2-ENSCM-UM1, C2M Universite Montpellier 2, CC 1504 Place Eugene Bataillon, 34095 Montpellier Cedex 5 (France)

    2012-07-25

    Highlights: Black-Right-Pointing-Pointer Reliable preparation method of thermoelectric materials. Black-Right-Pointing-Pointer Formation of zinc antimonide by the combustion synthesis method is investigated. Black-Right-Pointing-Pointer XRD and Raman spectroscopy as a function of temperature. Black-Right-Pointing-Pointer SHS: a new way for synthesizing thermoelectric materials. - Abstract: Due to the interesting properties of Zn{sub 4}Sb{sub 3} thermoelectric material, a reliable preparation method of this material is required. In this study, the formation of zinc antimonides by the combustion synthesis method is investigated and subjected to characterization using X-ray diffraction and Raman spectroscopy as a function of temperature. The results show that combustion synthesis can be a new way for synthesizing these thermoelectric materials.

  11. Critical review of thermoelectrics in modern power generation applications

    Directory of Open Access Journals (Sweden)

    Saqr Khalid M.

    2009-01-01

    Full Text Available The thermoelectric complementary effects have been discovered in the nineteenth century. However, their role in engineering applications has been very limited until the first half of the twentieth century, the beginning of space exploration era. Radioisotope thermoelectric generators have been the actual motive for the research community to develop efficient, reliable and advanced thermoelectrics. The efficiency of thermoelectric materials has been doubled several times during the past three decades. Nevertheless, there are numerous challenges to be resolved in order to develop thermoelectric systems for our modern applications. This paper discusses the recent advances in thermoelectric power systems and sheds the light on the main problematic concerns which confront contemporary research efforts in that field.

  12. Thermoelectric properties of Al doped Mg{sub 2}Si material

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Kulwinder, E-mail: kulwindercmp@gmail.com; Kumar, Ranjan [Department of Physics, Center of Advanced Study in Physics, Panjab University, Chandigarh-160 014 (India); Rani, Anita [Department of Physics, Center of Advanced Study in Physics, Panjab University, Chandigarh-160 014 (India); Guru Nanak College for Girls, Sri Muktsar Sahib, Punjab (India)

    2015-08-28

    In the present paper we have calculated thermoelectric properties of Al doped Mg{sub 2}Si material (Mg{sub 2−x}Al{sub x}Si, x=0.06) using Pseudo potential plane wave method based on DFT and Semi classical Boltzmann theory. The calculations showed n-type conduction, indicating that the electrical conduction are due to electron. The electrical conductivity increasing with increasing temperature and the negative value of Seebeck Coefficient also show that the conduction is due to electron. The thermal conductivity was increased slightly by Al doping with increasing temperature due to the much larger contribution of lattice thermal conductivity over electronic thermal conductivity.

  13. Anisotropic Thermoelectric Devices Made from Single-Crystal Semimetal Microwires in Glass Coating

    Science.gov (United States)

    Konopko, L. A.; Nikolaeva, A. A.; Kobylianskaya, A. K.; Huber, T. E.

    2018-04-01

    Thermoelectric heat conversion based on the Seebeck and Peltier effects generated at the junction between two materials of type-n and type-p is well known. Here, we present a demonstration of an unconventional thermoelectric energy conversion that is based on a single element made of an anisotropic material. In such materials, a heat flow generates a transverse thermoelectric electric field lying across the heat flow. Potentially, in applications involving miniature devices, the anisotropic thermoelectric (AT) effect has the advantage over traditional thermoelectrics that it simplifies the thermoelectric generator architecture. This is because the generator can be made of a single thermoelectric material without the complexity of a series of contacts forming a pile. A feature of anisotropic thermoelectrics is that the thermoelectric voltage is proportional to the element length and inversely proportional to the effective thickness. The AT effect has been demonstrated with artificial anisotropic thin film consisting of layers of alternating thermoelectric type, but there has been no demonstration of this effect in a long single-crystal. Electronic transport measurements have shown that the semimetal bismuth is highly anisotropic. We have prepared an experimental sample consisting of a 10-m-long glass-insulated single-crystal tin-doped bismuth microwire (d = 4 μm). Crucial for this experiment is the ability to grow the microwire as a single-crystal using a technique of recrystallization with laser heating and under a strong electric field. The sample was wound as a spiral, bonded to a copper disk, and used in various experiments. The sensitivity of the sample to heat flow is as high as 10-2 V/W with a time constant τ of about 0.5 s.

  14. Anisotropic Thermoelectric Devices Made from Single-Crystal Semimetal Microwires in Glass Coating

    Science.gov (United States)

    Konopko, L. A.; Nikolaeva, A. A.; Kobylianskaya, A. K.; Huber, T. E.

    2018-06-01

    Thermoelectric heat conversion based on the Seebeck and Peltier effects generated at the junction between two materials of type- n and type- p is well known. Here, we present a demonstration of an unconventional thermoelectric energy conversion that is based on a single element made of an anisotropic material. In such materials, a heat flow generates a transverse thermoelectric electric field lying across the heat flow. Potentially, in applications involving miniature devices, the anisotropic thermoelectric (AT) effect has the advantage over traditional thermoelectrics that it simplifies the thermoelectric generator architecture. This is because the generator can be made of a single thermoelectric material without the complexity of a series of contacts forming a pile. A feature of anisotropic thermoelectrics is that the thermoelectric voltage is proportional to the element length and inversely proportional to the effective thickness. The AT effect has been demonstrated with artificial anisotropic thin film consisting of layers of alternating thermoelectric type, but there has been no demonstration of this effect in a long single-crystal. Electronic transport measurements have shown that the semimetal bismuth is highly anisotropic. We have prepared an experimental sample consisting of a 10-m-long glass-insulated single-crystal tin-doped bismuth microwire ( d = 4 μm). Crucial for this experiment is the ability to grow the microwire as a single-crystal using a technique of recrystallization with laser heating and under a strong electric field. The sample was wound as a spiral, bonded to a copper disk, and used in various experiments. The sensitivity of the sample to heat flow is as high as 10-2 V/W with a time constant τ of about 0.5 s.

  15. Effect of Thermal Cycling on Zinc Antimonide Thin Film Thermoelectric Characteristics

    DEFF Research Database (Denmark)

    Mirhosseini, M.; Rezania, A.; Rosendahl, L.

    2017-01-01

    In this study, performance and stability of zinc antimonide thin film thermoelectric sample is analyzed under transient thermal conditions. The thermoelectric materials are deposited on glass based substrate where the heat flow is parallel with the thermoelectric element length. The specimen...

  16. Thermoelectric Properties of Two-Dimensional Molybdenum-based MXenes

    KAUST Repository

    Kim, Hyunho

    2017-07-05

    MXenes are an interesting class of 2D materials consisting of transition metal carbides and nitrides, which are currently a subject of extensive studies. Although there have been theoretical calculations estimating the thermoelectric properties of MXenes, no experimental measurements have been reported so far. In this report, three compositions of Mo-based MXenes (Mo2CTx, Mo2TiC2Tx, and Mo2Ti2C3Tx) have been synthesized and processed into free-standing binder-free papers by vacuum-assisted filtration, and their electrical and thermoelectric properties are measured. Upon heating to 800 K, these MXene papers exhibit high conductivity and n-type Seebeck coefficient. The thermoelectric power reaches 3.09×10-4 W m-1 K-2 at 803 K for the Mo2TiC2Tx MXene. While the thermoelectric properties of MXenes do not reach that of the best materials, they exceed their parent ternary and quaternary layered carbides. Mo2TiC2Tx shows the highest electrical conductivity in combination with the largest Seebeck coefficient of the three 2D materials studied.

  17. Energy materials coordinating committee (EMaCC). Annual technical report, fiscal year 1998

    Energy Technology Data Exchange (ETDEWEB)

    none,

    1999-07-31

    The FY 1998 budget summary for DOE Materials Activities is presented on pages 7 and 8. The distribution of these funds between DOE laboratories, private industry, academia and other organizations is presented in tabular form on page 9. Following the budget summary is a set of detailed program descriptions for the FY 1998 DOE Materials activities. These descriptions are presented according to the organizational structure of the Department. A mission statement, a budget summary listing the project titles and FY 1998 funding, and detailed project summaries are presented for each Assistant Secretary office and the Office of Energy Research. The project summaries also provide DOE, laboratory, academic and industrial contacts for each project, as appropriate.

  18. Nanostructured Bulk Thermoelectric Generator for Efficient Power Harvesting for Self-powered Sensor Networks

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yanliang [Idaho National Lab. (INL), Idaho Falls, ID (United States); Butt, Darryl [Idaho National Lab. (INL), Idaho Falls, ID (United States); Agarwal, Vivek [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-07-01

    The objective of this Nuclear Energy Enabling Technology research project is to develop high-efficiency and reliable thermoelectric generators for self-powered wireless sensors nodes utilizing thermal energy from nuclear plant or fuel cycle. The power harvesting technology has crosscutting significance to address critical technology gaps in monitoring nuclear plants and fuel cycle. The outcomes of the project will lead to significant advancement in sensors and instrumentation technology, reducing cost, improving monitoring reliability and therefore enhancing safety. The self-powered wireless sensor networks could support the long-term safe and economical operation of all the reactor designs and fuel cycle concepts, as well as spent fuel storage and many other nuclear science and engineering applications. The research is based on recent breakthroughs in high-performance nanostructured bulk (nanobulk) thermoelectric materials that enable high-efficiency direct heat-to-electricity conversion over a wide temperature range. The nanobulk thermoelectric materials that the research team at Boise State University and University of Houston has developed yield up to a 50% increase in the thermoelectric figure of merit, ZT, compared with state-of-the-art bulk counterparts. This report focuses on the selection of optimal thermoelectric materials for this project. The team has performed extensive study on two thermoelectric materials systems, i.e. the half-Heusler materials, and the Bismuth-Telluride materials. The report contains our recent research results on the fabrication, characterization and thermoelectric property measurements of these two materials.

  19. Opto-thermoelectric nanotweezers

    Science.gov (United States)

    Lin, Linhan; Wang, Mingsong; Peng, Xiaolei; Lissek, Emanuel N.; Mao, Zhangming; Scarabelli, Leonardo; Adkins, Emily; Coskun, Sahin; Unalan, Husnu Emrah; Korgel, Brian A.; Liz-Marzán, Luis M.; Florin, Ernst-Ludwig; Zheng, Yuebing

    2018-04-01

    Optical manipulation of plasmonic nanoparticles provides opportunities for fundamental and technical innovation in nanophotonics. Optical heating arising from the photon-to-phonon conversion is considered as an intrinsic loss in metal nanoparticles, which limits their applications. We show here that this drawback can be turned into an advantage, by developing an extremely low-power optical tweezing technique, termed opto-thermoelectric nanotweezers. By optically heating a thermoplasmonic substrate, a light-directed thermoelectric field can be generated due to spatial separation of dissolved ions within the heating laser spot, which allows us to manipulate metal nanoparticles of a wide range of materials, sizes and shapes with single-particle resolution. In combination with dark-field optical imaging, nanoparticles can be selectively trapped and their spectroscopic response can be resolved in situ. With its simple optics, versatile low-power operation, applicability to diverse nanoparticles and tunable working wavelength, opto-thermoelectric nanotweezers will become a powerful tool in colloid science and nanotechnology.

  20. High-performance and flexible thermoelectric films by screen printing solution-processed nanoplate crystals.

    Science.gov (United States)

    Varghese, Tony; Hollar, Courtney; Richardson, Joseph; Kempf, Nicholas; Han, Chao; Gamarachchi, Pasindu; Estrada, David; Mehta, Rutvik J; Zhang, Yanliang

    2016-09-12

    Screen printing allows for direct conversion of thermoelectric nanocrystals into flexible energy harvesters and coolers. However, obtaining flexible thermoelectric materials with high figure of merit ZT through printing is an exacting challenge due to the difficulties to synthesize high-performance thermoelectric inks and the poor density and electrical conductivity of the printed films. Here, we demonstrate high-performance flexible films and devices by screen printing bismuth telluride based nanocrystal inks synthesized using a microwave-stimulated wet-chemical method. Thermoelectric films of several tens of microns thickness were screen printed onto a flexible polyimide substrate followed by cold compaction and sintering. The n-type films demonstrate a peak ZT of 0.43 along with superior flexibility, which is among the highest reported ZT values in flexible thermoelectric materials. A flexible thermoelectric device fabricated using the printed films produces a high power density of 4.1 mW/cm(2) with 60 °C temperature difference between the hot side and cold side. The highly scalable and low cost process to fabricate flexible thermoelectric materials and devices demonstrated here opens up many opportunities to transform thermoelectric energy harvesting and cooling applications.

  1. Laser assisted hybrid additive manufacturing of thermoelectric modules

    Science.gov (United States)

    Zhang, Tao; Tewolde, Mahder; Longtin, Jon P.; Hwang, David J.

    2017-02-01

    Thermoelectric generators (TEGs) are an attractive means to produce electricity, particular from waste heat applications. However, TEGs are almost exclusively manufactured as flat, rigid modules of limited size and shape, and therefore an appropriate mounting for intimate contact of TEGs modules onto arbitrary surfaces represents a significant challenge. In this study, we introduce laser assisted additive manufacturing method to produce multi-layered thermoelectric generator device directly on flat and non-flat surfaces for waste heat recovery. The laser assisted processing spans from laser scribing of thermal sprayed thin films, curing of dispensed thermoelectric inks and selective laser sintering to functionalize thermoelectric materials.

  2. Searching for new thermoelectrics in chemically and structurally complex bismuth chalcogenides

    Energy Technology Data Exchange (ETDEWEB)

    Chung, D Y; Hogan, T; Schindler, J; Iordanidis, L; Brazis, P; Kannewurf, C R; Chen, B; Uher, C; Kanatzidis, M G

    1997-07-01

    A solid state chemistry synthetic approach towards identifying new materials with potentially superior thermoelectric properties is presented. Materials with complex compositions and structures also have complex electronic structures which may give rise to high thermoelectric powers and at the same time possess low thermal conductivities. The structures and thermoelectric properties of several new promising compounds with K-Bi-Se, K-Bi-S, Ba-Bi-Te, Cs-Bi-Te, and Rb-bi-Te are reported.

  3. Peridynamic Formulation for Coupled Thermoelectric Phenomena

    Directory of Open Access Journals (Sweden)

    Migbar Assefa

    2017-01-01

    Full Text Available Modeling of heat and electrical current flow simultaneously in thermoelectric convertor using classical theories do not consider the influence of defects in the material. This is because traditional methods are developed based on partial differential equations (PDEs and lead to infinite fluxes at the discontinuities. The usual way of solving such PDEs is by using numerical technique, like Finite Element Method (FEM. Although FEM is robust and versatile, it is not suitable to model evolving discontinuities. To avoid such shortcomings, we propose the concept of peridynamic theory to derive the balance of energy and charge equations in the coupled thermoelectric phenomena. Therefore, this paper presents the transport of heat and charge in thermoelectric material in the framework of peridynamic (PD theory. To illustrate the reliability of the PD formulation, numerical examples are presented and results are compared with those from literature, analytical solutions, or finite element solutions.

  4. Potency of Thermoelectric Generator for Hybrid Vehicle

    Directory of Open Access Journals (Sweden)

    Nandy Putra

    2010-10-01

    Full Text Available Thermoelectric Generator (TEG has been known as electricity generation for many years. If the temperature difference occurred between two difference semi conductor materials, the current will flow in the material and produced difference voltage. This principle is known as Seebeck effect that is the opposite of Peltier effect Thermoelectric Cooling (TEC. This research was conducted to test the potential of electric source from twelve peltier modules. Then, these thermoelectric generators were applied in hybrid car by using waste heat from the combustion engine. The experiment has been conducted with variations of peltier module arrangements (series and parallels and heater as heat source for the thermoelectric generator, with variations of heater voltage input (110V and 220V applied. The experimental result showed that twelve of peltier modules arranged in series and heater voltage of 220V generated power output of 8.11 Watts with average temperature difference of 42.82°C. This result shows that TEG has a bright prospect as alternative electric source.

  5. Thermoelectric generators: A review of applications

    International Nuclear Information System (INIS)

    Champier, Daniel

    2017-01-01

    Highlights: • This paper reviews the state of the art of thermoelectric generators. • The latest thermoelectric modules are introduced. • Waste heat recovery in transport and industry with thermoelectric generators. • Domestic and industrial applications of thermoelectric generators. • Thermoelectric generators in space, micro-generation and solar conversion. - Abstract: In past centuries, men have mainly looked to increase their production of energy in order to develop their industry, means of transport and quality of life. Since the recent energy crisis, researchers and industrials have looked mainly to manage energy in a better way, especially by increasing energy system efficiency. This context explains the growing interest for thermoelectric generators. Today, thermoelectric generators allow lost thermal energy to be recovered, energy to be produced in extreme environments, electric power to be generated in remote areas and microsensors to be powered. Direct solar thermal energy can also be used to produce electricity. This review begins with the basic principles of thermoelectricity and a presentation of existing and future materials. Design and optimization of generators are addressed. Finally in this paper, we developed an exhaustive presentation of thermoelectric generation applications covering electricity generation in extreme environments, waste heat recovery in transport and industry, domestic production in developing and developed countries, micro-generation for sensors and microelectronics and solar thermoelectric generators. Many recent applications are presented, as well as the future applications which are currently being studied in research laboratories or in industry. The main purpose of this paper is to clearly demonstrate that, almost anywhere in industry or in domestic uses, it is worth checking whether a TEG can be added whenever heat is moving from a hot source to a cold source.

  6. Design, Modeling, Fabrication, and Evaluation of Thermoelectric Generators with Hot-Wire Chemical Vapor Deposited Polysilicon as Thermoelement Material

    Science.gov (United States)

    de Leon, Maria Theresa; Tarazona, Antulio; Chong, Harold; Kraft, Michael

    2014-11-01

    This paper presents the design, modeling, fabrication, and evaluation of thermoelectric generators (TEGs) with p-type polysilicon deposited by hot-wire chemical vapor deposition (HWCVD) as thermoelement material. A thermal model is developed based on energy balance and heat transfer equations using lumped thermal conductances. Several test structures were fabricated to allow characterization of the boron-doped polysilicon material deposited by HWCVD. The film was found to be electrically active without any post-deposition annealing. Based on the tests performed on the test structures, it is determined that the Seebeck coefficient, thermal conductivity, and electrical resistivity of the HWCVD polysilicon are 113 μV/K, 126 W/mK, and 3.58 × 10-5 Ω m, respectively. Results from laser tests performed on the fabricated TEG are in good agreement with the thermal model. The temperature values derived from the thermal model are within 2.8% of the measured temperature values. For a 1-W laser input, an open-circuit voltage and output power of 247 mV and 347 nW, respectively, were generated. This translates to a temperature difference of 63°C across the thermoelements. This paper demonstrates that HWCVD, which is a cost-effective way of producing solar cells, can also be applied in the production of TEGs. By establishing that HWCVD polysilicon can be an effective thermoelectric material, further work on developing photovoltaic-thermoelectric (PV-TE) hybrid microsystems that are cost-effective and better performing can be explored.

  7. Hierarchical thermoelectrics : Crystal grain boundaries as scalable phonon scatterers

    NARCIS (Netherlands)

    Selli, Daniele; Boulfelfel, Salah Eddine; Schapotschnikow, PZ; Donadio, Davide; Leoni, Stefano

    2016-01-01

    Thermoelectric materials are strategically valuable for sustainable development, as they allow for the generation of electrical energy from wasted heat. In recent years several strategies have demonstrated some efficiency in improving thermoelectric properties. Dopants affect carrier

  8. Thermoelectric Generation Of Current - Theoretical And Experimental Analysis

    Science.gov (United States)

    Ruciński, Adam; Rusowicz, Artur

    2017-12-01

    This paper provides some information about thermoelectric technology. Some new materials with improved figures of merit are presented. These materials in Peltier modules make it possible to generate electric current thanks to a temperature difference. The paper indicates possible applications of thermoelectric modules as interesting tools for using various waste heat sources. Some zero-dimensional equations describing the conditions of electric power generation are given. Also, operating parameters of Peltier modules, such as voltage and electric current, are analyzed. The paper shows chosen characteristics of power generation parameters. Then, an experimental stand for ongoing research and experimental measurements are described. The authors consider the resistance of a receiver placed in the electric circuit with thermoelectric elements. Finally, both the analysis of experimental results and conclusions drawn from theoretical findings are presented. Voltage generation of about 1.5 to 2.5 V for the temperature difference from 65 to 85 K was observed when a bismuth telluride thermoelectric couple (traditionally used in cooling technology) was used.

  9. Chemical Potential Tuning and Enhancement of Thermoelectric Properties in Indium Selenides.

    Science.gov (United States)

    Rhyee, Jong-Soo; Kim, Jin Hee

    2015-03-20

    Researchers have long been searching for the materials to enhance thermoelectric performance in terms of nano scale approach in order to realize phonon-glass-electron-crystal and quantum confinement effects. Peierls distortion can be a pathway to enhance thermoelectric figure-of-merit ZT by employing natural nano-wire-like electronic and thermal transport. The phonon-softening known as Kohn anomaly, and Peierls lattice distortion decrease phonon energy and increase phonon scattering, respectively, and, as a result, they lower thermal conductivity. The quasi-one-dimensional electrical transport from anisotropic band structure ensures high Seebeck coefficient in Indium Selenide. The routes for high ZT materials development of In₄Se₃ - δ are discussed from quasi-one-dimensional property and electronic band structure calculation to materials synthesis, crystal growth, and their thermoelectric properties investigations. The thermoelectric properties of In₄Se₃ - δ can be enhanced by electron doping, as suggested from the Boltzmann transport calculation. Regarding the enhancement of chemical potential, the chlorine doped In₄Se₃ - δ Cl 0.03 compound exhibits high ZT over a wide temperature range and shows state-of-the-art thermoelectric performance of ZT = 1.53 at 450 °C as an n -type material. It was proven that multiple elements doping can enhance chemical potential further. Here, we discuss the recent progress on the enhancement of thermoelectric properties in Indium Selenides by increasing chemical potential.

  10. Thermoelectric effect in nano-scaled lanthanides doped ZnO

    Energy Technology Data Exchange (ETDEWEB)

    Otal, E H; Canepa, H R; Walsoee de Reca, N E [Centro de Investigacion en Solidos, CITEFA, San Juan Bautista de La Salle 4397 (B1603ALO) Villa Martelli, Buenos Aires (Argentina); Schaeuble, N; Aguirre, M H, E-mail: canepa@citefa.gov.a, E-mail: myriam.aguirre@empa.c [Solid State Chemistry and Catalysis, Empa, Swiss Federal Laboratories for Materials Testing and Research, Ueberlandstrasse 129, CH-8600 Duebendorf (Switzerland)

    2009-05-01

    Start Nano-scaled ZnO with 1% Er doping was prepared by soft chemistry methods. The synthesis was carried out in anhydrous polar solvent to achieve a crystal size of a few nanometers. Resulting particles were processed as precipitates or multi layer films. Structural characterization was evaluated by X-Ray diffraction and transmission and scanning electron microscopy. In the case of films, UV-Vis characterization was made. The thermoelectrical properties of ZnO:Er were evaluated and compared with a typical good thermoelectric material ZnO:Al. Both materials have also shown high Seebeck coefficients and they can be considered as potential compounds for thermoelectric conversion.

  11. Thermoelectric properties of SnSe compound

    Energy Technology Data Exchange (ETDEWEB)

    Guan, Xinhong [State Key Laboratory of Information Photonics and Optical Communications, Ministry of Education, Beijing University of Posts and Telecommunications, P.O. Box 72, Beijing 100876 (China); Lu, Pengfei, E-mail: photon@bupt.edu.cn [State Key Laboratory of Information Photonics and Optical Communications, Ministry of Education, Beijing University of Posts and Telecommunications, P.O. Box 72, Beijing 100876 (China); Wu, Liyuan; Han, Lihong [State Key Laboratory of Information Photonics and Optical Communications, Ministry of Education, Beijing University of Posts and Telecommunications, P.O. Box 72, Beijing 100876 (China); Liu, Gang [School of Electronic Engineering, Beijing University of Posts and Telecommunications, Beijing 100876 (China); Song, Yuxin [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China); Wang, Shumin [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China); Photonics Laboratory, Department of Microtechnology and Nanoscience, Chalmers University of Technology, 41296 Gothenburg (Sweden)

    2015-09-15

    Highlights: • The electronic and thermoelectric properties of SnSe bulk material are studied. • The ZT can reach as high as 1.87 along yy and 1.6 along zz direction at 800k. • SnSe is an indirect-band material, and SOC has little effect on the band structure. • The high ZT can be attributed to the intrinsically ultralow thermal conductivity. - Abstract: A first-principles study and Boltzmann transport theory have been performed to evaluate the electronic structure and thermoelectric properties of SnSe compound. The energy band structure and density of states are studied in detail. The electronic transport coefficients are then calculated as a function of chemical potential or temperature within the assumption of the constant relaxation time. The figure of merit ZT is obtained with the use of calculated thermoelectric properties and can reach as high as 1.87 along yy and 1.6 along zz direction at 800 K. Our theoretical result agrees well with previous experimental data.

  12. Thermoelectric properties of SnSe compound

    International Nuclear Information System (INIS)

    Guan, Xinhong; Lu, Pengfei; Wu, Liyuan; Han, Lihong; Liu, Gang; Song, Yuxin; Wang, Shumin

    2015-01-01

    Highlights: • The electronic and thermoelectric properties of SnSe bulk material are studied. • The ZT can reach as high as 1.87 along yy and 1.6 along zz direction at 800k. • SnSe is an indirect-band material, and SOC has little effect on the band structure. • The high ZT can be attributed to the intrinsically ultralow thermal conductivity. - Abstract: A first-principles study and Boltzmann transport theory have been performed to evaluate the electronic structure and thermoelectric properties of SnSe compound. The energy band structure and density of states are studied in detail. The electronic transport coefficients are then calculated as a function of chemical potential or temperature within the assumption of the constant relaxation time. The figure of merit ZT is obtained with the use of calculated thermoelectric properties and can reach as high as 1.87 along yy and 1.6 along zz direction at 800 K. Our theoretical result agrees well with previous experimental data

  13. Proposal for a phase-coherent thermoelectric transistor

    International Nuclear Information System (INIS)

    Giazotto, F.; Robinson, J. W. A.; Moodera, J. S.; Bergeret, F. S.

    2014-01-01

    Identifying materials and devices which offer efficient thermoelectric effects at low temperature is a major obstacle for the development of thermal management strategies for low-temperature electronic systems. Superconductors cannot offer a solution since their near perfect electron-hole symmetry leads to a negligible thermoelectric response; however, here we demonstrate theoretically a superconducting thermoelectric transistor which offers unparalleled figures of merit of up to ∼45 and Seebeck coefficients as large as a few mV/K at sub-Kelvin temperatures. The device is also phase-tunable meaning its thermoelectric response for power generation can be precisely controlled with a small magnetic field. Our concept is based on a superconductor-normal metal-superconductor interferometer in which the normal metal weak-link is tunnel coupled to a ferromagnetic insulator and a Zeeman split superconductor. Upon application of an external magnetic flux, the interferometer enables phase-coherent manipulation of thermoelectric properties whilst offering efficiencies which approach the Carnot limit

  14. Proposal for a phase-coherent thermoelectric transistor

    Energy Technology Data Exchange (ETDEWEB)

    Giazotto, F., E-mail: giazotto@sns.it [NEST, Instituto Nanoscienze-CNR and Scuola Normale Superiore, I-56127 Pisa (Italy); Robinson, J. W. A., E-mail: jjr33@cam.ac.uk [Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS (United Kingdom); Moodera, J. S. [Department of Physics and Francis Bitter Magnet Lab, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Bergeret, F. S., E-mail: sebastian-bergeret@ehu.es [Centro de Física de Materiales (CFM-MPC), Centro Mixto CSIC-UPV/EHU, Manuel de Lardizabal 4, E-20018 San Sebastián (Spain); Donostia International Physics Center (DIPC), Manuel de Lardizabal 5, E-20018 San Sebastián (Spain)

    2014-08-11

    Identifying materials and devices which offer efficient thermoelectric effects at low temperature is a major obstacle for the development of thermal management strategies for low-temperature electronic systems. Superconductors cannot offer a solution since their near perfect electron-hole symmetry leads to a negligible thermoelectric response; however, here we demonstrate theoretically a superconducting thermoelectric transistor which offers unparalleled figures of merit of up to ∼45 and Seebeck coefficients as large as a few mV/K at sub-Kelvin temperatures. The device is also phase-tunable meaning its thermoelectric response for power generation can be precisely controlled with a small magnetic field. Our concept is based on a superconductor-normal metal-superconductor interferometer in which the normal metal weak-link is tunnel coupled to a ferromagnetic insulator and a Zeeman split superconductor. Upon application of an external magnetic flux, the interferometer enables phase-coherent manipulation of thermoelectric properties whilst offering efficiencies which approach the Carnot limit.

  15. Nanocomposites with High Thermoelectric Figures of Merit

    Science.gov (United States)

    Chen, Gang (Inventor); Dresselhaus, Mildred (Inventor); Ren, Zhifeng (Inventor)

    2015-01-01

    The present invention is generally directed to nanocomposite thermoelectric materials that exhibit enhanced thermoelectric properties. The nanocomposite materials include two or more components, with at least one of the components forming nano-sized structures within the composite material. The components are chosen such that thermal conductivity of the composite is decreased without substantially diminishing the composite's electrical conductivity. Suitable component materials exhibit similar electronic band structures. For example, a band-edge gap between at least one of a conduction band or a valence band of one component material and a corresponding band of the other component material at interfaces between the components can be less than about 5k(sub B)T, wherein k(sub B) is the Boltzman constant and T is an average temperature of said nanocomposite composition.

  16. Instrument for measuring metal-thermoelectric semiconductor contact resistence

    International Nuclear Information System (INIS)

    Lanxner, M.; Nechmadi, M.; Meiri, B.; Schildkraut, I.

    1979-02-01

    An instrument for measuring electrical, metal-thermoelectric semiconductor contact resistance is described. The expected errors of measurement are indicated. The operation of the instrument which is based on potential traversing perpendicularly to the contact plane is illustrated for the case of contacts of palladium and bismuth telluride-based thermoelectric material

  17. Thermoelectric properties and performance of flexible reduced graphene oxide films up to 3,000 K

    Science.gov (United States)

    Li, Tian; Pickel, Andrea D.; Yao, Yonggang; Chen, Yanan; Zeng, Yuqiang; Lacey, Steven D.; Li, Yiju; Wang, Yilin; Dai, Jiaqi; Wang, Yanbin; Yang, Bao; Fuhrer, Michael S.; Marconnet, Amy; Dames, Chris; Drew, Dennis H.; Hu, Liangbing

    2018-02-01

    The development of ultrahigh-temperature thermoelectric materials could enable thermoelectric topping of combustion power cycles as well as extending the range of direct thermoelectric power generation in concentrated solar power. However, thermoelectric operation temperatures have been restricted to under 1,500 K due to the lack of suitable materials. Here, we demonstrate a thermoelectric conversion material based on high-temperature reduced graphene oxide nanosheets that can perform reliably up to 3,000 K. After a reduction treatment at 3,300 K, the nanosheet film exhibits an increased conductivity to 4,000 S cm-1 at 3,000 K and a high power factor S2σ = 54.5 µW cm-1 K-2. We report measurements characterizing the film's thermoelectric properties up to 3,000 K. The reduced graphene oxide film also exhibits a high broadband radiation absorbance and can act as both a radiative receiver and a thermoelectric generator. The printable, lightweight and flexible film is attractive for system integration and scalable manufacturing.

  18. Potential thermoelectric performance of hole-doped Cu2O

    International Nuclear Information System (INIS)

    Chen, Xin; Parker, David; Du, Mao-Hua; Singh, David J

    2013-01-01

    High thermoelectric performance in oxides requires stable conductive materials that have suitable band structures. Here we show, based on an analysis of the thermopower and related properties using first-principles calculations and Boltzmann transport theory in the relaxation time approximation, that hole-doped Cu 2 O may be such a material. We find that hole-doped Cu 2 O has a high thermopower of above 200 μV K −1 even with doping levels as high as 5.2 × 10 20 cm −3 at 500 K, mainly attributed to the heavy valence bands of Cu 2 O. This is reminiscent of the cobaltate family of high-performance oxide thermoelectrics and implies that hole-doped Cu 2 O could be an excellent thermoelectric material if suitably doped. (paper)

  19. Increasing the thermoelectric power factor of Ge17Sb2Te20 by adjusting the Ge/Sb ratio

    Science.gov (United States)

    Williams, Jared B.; Mather, Spencer P.; Page, Alexander; Uher, Ctirad; Morelli, Donald T.

    2017-07-01

    We have investigated the thermoelectric properties of Ge17Sb2Te20. This compound is a known phase change material with electronic properties that depend strongly on temperature. The thermoelectric properties of this compound can be tuned by altering the stoichiometry of Ge and Sb without the use of additional foreign elements during synthesis. This tuning results in a 26% increase in the thermoelectric power factor at 723 K. Based on a single parabolic band model we show that the pristine material is optimally doped, and thus, a reduction in the lattice thermal conductivity of pure Ge17Sb2Te20 should result in an enhanced thermoelectric figure of merit.

  20. Prediction of the High Thermoelectric Performance of Pnictogen Dichalcogenide Layered Compounds with Quasi-One-Dimensional Gapped Dirac-like Band Dispersion

    Science.gov (United States)

    Ochi, Masayuki; Usui, Hidetomo; Kuroki, Kazuhiko

    2017-12-01

    Thermoelectric power generation has been recognized as one of the most important technologies, and high-performance thermoelectric materials have long been pursued. However, because of the large number of candidate materials, this quest is extremely challenging, and it has become clear that a firm theoretical concept from the viewpoint of band-structure engineering is needed. We theoretically demonstrate that pnictogen dichalcogenide layered compounds, which originally attracted attention as a family of superconductors and have recently been investigated as thermoelectric materials, can exhibit very high thermoelectric performance with elemental substitution. Specifically, we clarify a promising guiding principle for material design and find that LaOAsSe2, a material that has yet to be synthesized, has a power factor that is 6 times as large as that of the known compound LaOBiS2 and can exhibit a very large Z T under some plausible assumptions. This large enhancement of the thermoelectric performance originates from the quasi-one-dimensional gapped Dirac-like band dispersion, which is realized by the square-lattice network. We offer one ideal limit of the band structure for thermoelectric materials. Because our target materials have high controllability of constituent elements and feasibility of carrier doping, experimental studies along this line are eagerly awaited.

  1. Thermoelectric Properties of the XCoSb (X: Ti,Zr,Hf) Half-Heusler Alloys

    KAUST Repository

    Gandi, Appala

    2017-09-18

    We investigate the thermoelectric properties of the half-Heusler alloys XCoSb (X: Ti,Zr,Hf) by solving Boltzmann transport equations and discuss them in terms of the electronic band structure. The rigid band approximation is employed to address the effects of doping. While many half-Heuser alloys show excellent thermoelectric performance, the materials under study are special by supporting both n- and p-doping. We identify the reasons for this balanced thermoelectric transport and explain why experimentally p-doping is superior to n-doping. We also determine the spectrum of phonon mean free paths to guide grain refinement methods to enhance the thermoelectric figure of merit.

  2. Chemical Potential Tuning and Enhancement of Thermoelectric Properties in Indium Selenides

    Directory of Open Access Journals (Sweden)

    Jong-Soo Rhyee

    2015-03-01

    Full Text Available Researchers have long been searching for the materials to enhance thermoelectric performance in terms of nano scale approach in order to realize phonon-glass-electron-crystal and quantum confinement effects. Peierls distortion can be a pathway to enhance thermoelectric figure-of-merit ZT by employing natural nano-wire-like electronic and thermal transport. The phonon-softening known as Kohn anomaly, and Peierls lattice distortion decrease phonon energy and increase phonon scattering, respectively, and, as a result, they lower thermal conductivity. The quasi-one-dimensional electrical transport from anisotropic band structure ensures high Seebeck coefficient in Indium Selenide. The routes for high ZT materials development of In4Se3−δ are discussed from quasi-one-dimensional property and electronic band structure calculation to materials synthesis, crystal growth, and their thermoelectric properties investigations. The thermoelectric properties of In4Se3−δ can be enhanced by electron doping, as suggested from the Boltzmann transport calculation. Regarding the enhancement of chemical potential, the chlorine doped In4Se3−δCl0.03 compound exhibits high ZT over a wide temperature range and shows state-of-the-art thermoelectric performance of ZT = 1.53 at 450 °C as an n-type material. It was proven that multiple elements doping can enhance chemical potential further. Here, we discuss the recent progress on the enhancement of thermoelectric properties in Indium Selenides by increasing chemical potential.

  3. New evaluation parameter for wearable thermoelectric generators

    Science.gov (United States)

    Wijethunge, Dimuthu; Kim, Woochul

    2018-04-01

    Wearable devices constitute a key application area for thermoelectric devices. However, owing to new constraints in wearable applications, a few conventional device optimization techniques are not appropriate and material evaluation parameters, such as figure of merit (zT) and power factor (PF), tend to be inadequate. We illustrated the incompleteness of zT and PF by performing simulations and considering different thermoelectric materials. The results indicate a weak correlation between device performance and zT and PF. In this study, we propose a new evaluation parameter, zTwearable, which is better suited for wearable applications compared to conventional zT. Owing to size restrictions, gap filler based device optimization is extremely critical in wearable devices. With respect to the occasions in which gap fillers are used, expressions for power, effective thermal conductivity (keff), and optimum load electrical ratio (mopt) are derived. According to the new parameters, the thermal conductivity of the material has become much more critical now. The proposed new evaluation parameter, namely, zTwearable, is extremely useful in the selection of an appropriate thermoelectric material among various candidates prior to the commencement of the actual design process.

  4. A lightweight scalable agarose-gel-synthesized thermoelectric composite

    Science.gov (United States)

    Kim, Jin Ho; Fernandes, Gustavo E.; Lee, Do-Joong; Hirst, Elizabeth S.; Osgood, Richard M., III; Xu, Jimmy

    2018-03-01

    Electronic devices are now advancing beyond classical, rigid systems and moving into lighweight flexible regimes, enabling new applications such as body-wearables and ‘e-textiles’. To support this new electronic platform, composite materials that are highly conductive yet scalable, flexible, and wearable are needed. Materials with high electrical conductivity often have poor thermoelectric properties because their thermal transport is made greater by the same factors as their electronic conductivity. We demonstrate, in proof-of-principle experiments, that a novel binary composite can disrupt thermal (phononic) transport, while maintaining high electrical conductivity, thus yielding promising thermoelectric properties. Highly conductive Multi-Wall Carbon Nanotube (MWCNT) composites are combined with a low-band gap semiconductor, PbS. The work functions of the two materials are closely matched, minimizing the electrical contact resistance within the composite. Disparities in the speed of sound in MWCNTs and PbS help to inhibit phonon propagation, and boundary layer scattering at interfaces between these two materials lead to large Seebeck coefficient (> 150 μV/K) (Mott N F and Davis E A 1971 Electronic Processes in Non-crystalline Materials (Oxford: Clarendon), p 47) and a power factor as high as 10 μW/(K2 m). The overall fabrication process is not only scalable but also conformal and compatible with large-area flexible hosts including metal sheets, films, coatings, possibly arrays of fibers, textiles and fabrics. We explain the behavior of this novel thermoelectric material platform in terms of differing length scales for electrical conductivity and phononic heat transfer, and explore new material configurations for potentially lightweight and flexible thermoelectric devices that could be networked in a textile.

  5. Reliable Thermoelectric Module Design under Opposing Requirements from Structural and Thermoelectric Considerations

    Science.gov (United States)

    Karri, Naveen K.; Mo, Changki

    2018-06-01

    Structural reliability of thermoelectric generation (TEG) systems still remains an issue, especially for applications such as large-scale industrial or automobile exhaust heat recovery, in which TEG systems are subject to dynamic loads and thermal cycling. Traditional thermoelectric (TE) system design and optimization techniques, focused on performance alone, could result in designs that may fail during operation as the geometric requirements for optimal performance (especially the power) are often in conflict with the requirements for mechanical reliability. This study focused on reducing the thermomechanical stresses in a TEG system without compromising the optimized system performance. Finite element simulations were carried out to study the effect of TE element (leg) geometry such as leg length and cross-sectional shape under constrained material volume requirements. Results indicated that the element length has a major influence on the element stresses whereas regular cross-sectional shapes have minor influence. The impact of TE element stresses on the mechanical reliability is evaluated using brittle material failure theory based on Weibull analysis. An alternate couple configuration that relies on the industry practice of redundant element design is investigated. Results showed that the alternate configuration considerably reduced the TE element and metallization stresses, thereby enhancing the structural reliability, with little trade-off in the optimized performance. The proposed alternate configuration could serve as a potential design modification for improving the reliability of systems optimized for thermoelectric performance.

  6. Effect of high fluence neutron irradiation on transport properties of thermoelectrics

    Science.gov (United States)

    Wang, H.; Leonard, K. J.

    2017-07-01

    Thermoelectric materials were subjected to high fluence neutron irradiation in order to understand the effect of radiation damage on transport properties. This study is relevant to the NASA Radioisotope Thermoelectric Generator (RTG) program in which thermoelectric elements are exposed to radiation over a long period of time in space missions. Selected n-type and p-type bismuth telluride materials were irradiated at the High Flux Isotope Reactor with a neutron fluence of 1.3 × 1018 n/cm2 (E > 0.1 MeV). The increase in the Seebeck coefficient in the n-type material was partially off-set by an increase in electrical resistivity, making the power factor higher at lower temperatures. For the p-type materials, although the Seebeck coefficient was not affected by irradiation, electrical resistivity decreased slightly. The figure of merit, zT, showed a clear drop in the 300-400 K range for the p-type material and an increase for the n-type material. Considering that the p-type and n-type materials are connected in series in a module, the overall irradiation damages at the device level were limited. These results, at neutron fluences exceeding a typical space mission, are significant to ensure that the radiation damage to thermoelectrics does not affect the performance of RTGs.

  7. The thermo-electric nature of the Debye temperature

    Directory of Open Access Journals (Sweden)

    Mithun Bhowmick

    2018-05-01

    Full Text Available The Debye temperature is typically associated with the heat capacity of a solid and the cut-off of the possible lattice vibrations, but not necessarily to the electric conductivity of the material. By investigating III-V and II-VI compound semiconductors, we reveal that the Debye temperature represents a thermo-electric material parameter, connecting the thermal and electronic properties of a solid via a distinct power law.

  8. Electronic, phononic, and thermoelectric properties of graphyne sheets

    International Nuclear Information System (INIS)

    Sevinçli, Hâldun; Sevik, Cem

    2014-01-01

    Electron, phonon, and thermoelectric transport properties of α-, β-, γ-, and 6,6,12-graphyne sheets are compared and contrasted with those of graphene. α-, β-, and 6,6,12-graphynes, with direction dependent Dirac dispersions, have higher electronic transmittance than graphene. γ-graphyne also attains better electrical conduction than graphene except at its band gap. Vibrationally, graphene conducts heat much more efficiently than graphynes, a behavior beyond an atomic density differences explanation. Seebeck coefficients of the considered Dirac materials are similar but thermoelectric power factors decrease with increasing effective speeds of light. γ-graphyne yields the highest thermoelectric efficiency with a thermoelectric figure of merit as high as ZT = 0.45, almost an order of magnitude higher than that of graphene

  9. Expanding the reduced-current approach for thermoelectric generators to achieve higher volumetric power density

    DEFF Research Database (Denmark)

    Wijesooriyage, Waruna Dissanayaka; Rosendahl, Lasse

    2015-01-01

    Thermoelectrics are candidate niche electrical generator devices for energy management. At present, scientists are more focused on thermoelectric (TE) material development, but the TE module design procedure is still in a relatively virgin state. One of the most well-known methods is the reduced ...

  10. Thermoelectric enhancement at low temperature in nonstoichiometric lead-telluride compounds

    International Nuclear Information System (INIS)

    Wang Heng; Li Jingfeng; Kita, Takuji

    2007-01-01

    Pb 1.17 Te thermoelectric polycrystalline materials were fabricated by mechanical alloying (MA) and spark plasma sintering (SPS). The property measurement and microstructural characterization showed that the present material has special features different from traditional Pb 1+x Te ingots with secondary Pb phase. An attractive enhancement of the thermoelectric figure of merit ZT = 0.64 was obtained at 450 K, with a low thermal conductivity of 1.11 W m -1 K -1 at this temperature. Transmission electron microscopy observation showed the existence of randomly dispersed nano features that are responsible for such enhancement, some of which are similar to the nanostructures reported in the AgPb m SbTe m+2 system. The origin of these regions is discussed and their influence on thermal conductivity is revealed. The results confirm the effectiveness of such a kind of nano feature in improving thermoelectric properties, especially in reducing thermal conductivity. They also indicate a new way of obtaining thermoelectric materials with such a kind of nano feature via MA and SPS

  11. Soluble Lead and Bismuth Chalcogenidometallates: Versatile Solders for Thermoelectric Materials

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Hao [Department; Son, Jae Sung [Department; School; Dolzhnikov, Dmitriy S. [Department; Filatov, Alexander S. [Department; Hazarika, Abhijit [Department; Wang, Yuanyuan [Department; Hudson, Margaret H. [Department; Sun, Cheng-Jun [Advanced; Chattopadhyay, Soma [Physical; Talapin, Dmitri V. [Department; Center

    2017-07-27

    Here we report the syntheses of largely unexplored lead and bismuth chalcogenidometallates in the solution phase. Using N2H4 as the solvent, new compounds such as K6Pb3Te6·7N2H4 were obtained. These soluble molecular compounds underwent cation exchange processes using resin chemistry, replacing Na+ or K+ by decomposable N2H5+ or tetraethylammonium cations. They also transformed into stoichiometric lead and bismuth chalcogenide nanomaterials with the addition of metal salts. Such a versatile chemistry led to a variety of composition-matched solders to join lead and bismuth chalcogenides and tune their charge transport properties at the grain boundaries. Solution-processed thin films composed of Bi0.5Sb1.5Te3 microparticles soldered by (N2H5)6Bi0.5Sb1.5Te6 exhibited thermoelectric power factors (~28 μW/cm K2) comparable to those in vacuum-deposited Bi0.5Sb1.5Te3 films. The soldering effect can also be integrated with attractive fabrication techniques for thermoelectric modules, such as screen printing, suggesting the potential of these solders in the rational design of printable and moldable thermoelectrics.

  12. Thermoelectric Conversion of Waste Heat to Electricity in an IC Engine Powered Vehicle

    Energy Technology Data Exchange (ETDEWEB)

    None

    2012-01-31

    The thermoelectric generator shorting system provides the capability to monitor and short-out individual thermoelectric couples in the event of failure. This makes the series configured thermoelectric generator robust to individual thermoelectric couple failure. Open circuit detection of the thermoelectric couples and the associated short control is a key technique to ensure normal functionality of the TE generator under failure of individual TE couples. This report describes a five-year effort whose goal was the understanding the issues related to the development of a thermoelectric energy recovery device for a Class-8 truck. Likely materials and important issues related to the utility of this generator were identified. Several prototype generators were constructed and demonstrated. The generators developed demonstrated several new concepts including advanced insulation, couple bypass technology and the first implementation of skutterudite thermoelectric material in a generator design. Additional work will be required to bring this system to fruition. However, such generators offer the possibility of converting energy that is otherwise wasted to useful electric power. Uur studies indicate that this can be accomplished in a cost-effective manner for this application.

  13. Thermoelectric conversion at the divertor plates and the first wall of a fusion reactor

    Energy Technology Data Exchange (ETDEWEB)

    Yamaguchi, S. [National Inst. for Fusion Science, Nagoya (Japan); Sagara, A. [National Inst. for Fusion Science, Nagoya (Japan); Komori, A. [National Inst. for Fusion Science, Nagoya (Japan); Tazima, T. [National Inst. for Fusion Science, Nagoya (Japan); Motojima, O. [National Inst. for Fusion Science, Nagoya (Japan); Iiyoshi, A. [National Inst. for Fusion Science, Nagoya (Japan); Matsubara, K. [National Inst. for Fusion Science, Nagoya (Japan)]|[Yamaguchi Univ. (Japan); Onozuka, M. [National Inst. for Fusion Science, Nagoya (Japan)]|[Mitsubishi Heavy Industries Ltd. (Japan); Koganezawa, K. [National Inst. for Fusion Science, Nagoya (Japan)]|[Mitsubishi Heavy Industries Ltd. (Japan); Matsuda, T. [National Inst. for Fusion Science, Nagoya (Japan)]|[Toyo Tanso Co. Ltd. (Japan)

    1995-12-31

    We investigated thermoelectric conversion on the first wall and the divertor plates. Carbon, B{sub 4}C, and other carbon-based materials were tested as components of a thermoelectric element. The heat flux from the plasma was assumed to be 400 kW/m{sup 2}, and the cooling side temperature the fixed design parameter of either 350 K or 650 K. While differential radiation cooling was not considered in this study, a computer programme was used to estimate the distribution of temperature and thermal stress over the thermoelectric element. The three-legged element was conceived to be 20 cm long and 12 cm wide. The temperature in its arches reached almost 2500 K, and the maximal thermal stress was 80 MPa - still within the acceptable range for the ITER design parameter. The high thermoelectric power of B{sub 4}C accounts for the thermal efficiency of 2.8% (for 650 K) or 3.3% (for 350 K). If we find an N-type semi-conductor material with the same high absolute value as B{sub 4}C to replace carbon, the efficiency will improve to 9.4% (for 650 K) or 11% (for 350 K). Since plasma is a current-conducting medium, we discuss aspects of a plasma-connected thermoelectric element. Its efficiency would depend on the connection length of magnetic field and plasma parameters near the wall. (orig.).

  14. Thermoelectric generation coupling methanol steam reforming characteristic in microreactor

    International Nuclear Information System (INIS)

    Wang, Feng; Cao, Yiding; Wang, Guoqiang

    2015-01-01

    Thermoelectric (TE) generator converts heat to electric energy by thermoelectric material. However, heat removal on the cold side of the generator represents a serious challenge. To address this problem and for improved energy conversion, a thermoelectric generation process coupled with methanol steam reforming (SR) for hydrogen production is designed and analyzed in this paper. Experimental study on the cold spot character in a micro-reactor with monolayer catalyst bed is first carried out to understand the endothermic nature of the reforming as the thermoelectric cold side. A novel methanol steam reforming micro-reactor heated by waste heat or methanol catalytic combustion for hydrogen production coupled with a thermoelectric generation module is then simulated. Results show that the cold spot effect exists in the catalyst bed under all conditions, and the associated temperature difference first increases and then decreases with the inlet temperature. In the micro-reactor, the temperature difference between the reforming and heating channel outlets decreases rapidly with an increase in thermoelectric material's conductivity coefficient. However, methanol conversion at the reforming outlet is mainly affected by the reactor inlet temperature; while at the combustion outlet, it is mainly affected by the reactor inlet velocity. Due to the strong endothermic effect of the methanol steam reforming, heat supply of both kinds cannot balance the heat needed at reactor local areas, resulting in the cold spot at the reactor inlet. When the temperature difference between the thermoelectric module's hot and cold sides is 22 K, the generator can achieve an output voltage of 55 mV. The corresponding molar fraction of hydrogen can reach about 62.6%, which corresponds to methanol conversion rate of 72.6%. - Highlights: • Cold spot character of methanol steam reforming was studied through experiment. • Thermoelectric generation Coupling MSR process has been

  15. Thermoelectric properties of ternary phases of thallium-tin-tellurium system

    Energy Technology Data Exchange (ETDEWEB)

    Dichi, E. [Equipe materiaux et sante, faculte de pharmacie, universite Paris XI, 5, rue J.B, EA 401, Clement 92296 Chatenay-Malabry (France)], E-mail: emma.dichi@cep.u-psud.fr; Sghaier, M. [Equipe materiaux et sante, faculte de pharmacie, universite Paris XI, 5, rue J.B, EA 401, Clement 92296 Chatenay-Malabry (France); Kra, G. [Laboratoire de chimie minerale, universite de Cocody, 22, BP 582, Abidjan 22, Cote d' Ivoire (France)

    2008-06-30

    In this paper, we present the measurements of conductivity and of thermoelectric power. Measurements were taken for the temperature range of 100-330 K for the three ternary phases of Tl-Sn-Te system. The potential of these compounds as thermoelectric materials was studied.

  16. Thermoelectric detection of inclusions in metallic biomaterials by magnetic sensing

    Directory of Open Access Journals (Sweden)

    Hector Carreon

    2017-05-01

    Full Text Available The detectability of small inclusions and subtle imperfections by magnetic measurements that senses thermoelectric currents produced by a temperature gradient is ultimately limited by the intrinsic thermoelectric anisotropy and inhomogeneity of the material to be inspected. The probability of detection (POD of a given material flaw is determined by the resulting signal-to-noise ratio rather than by the absolute magnitude of the signal itself. The strength of the magnetic field to be detected greatly depends on the physical nature of the host medium and dimensions of the imperfection. This paper presents experimental data for the magnetic field produced by thermoelectric currents around tin inclusions in different host medium such as 316LVM stainless steel and Ti-6Al-4V titanium alloy under external thermal excitation. The diameter of the inclusions and the lift-off distance varied from 0.39 to 3.175 mm and from 1 to 10 mm, respectively. A 0.6 °C/cm temperature gradient in the samples produced peak magnetic flux densities ranging from 0.1 to 280 nT, that was measured by a fluxgate magnetometer. The numerical results were found to be in good agreement with theoretical predictions and demonstrated that both property anisotropy and gradient in thermoelectric materials can significantly influence the induced thermoelectric currents and magnetic fields.

  17. Thermoelectric detection of inclusions in metallic biomaterials by magnetic sensing

    Science.gov (United States)

    Carreon, Hector

    2017-05-01

    The detectability of small inclusions and subtle imperfections by magnetic measurements that senses thermoelectric currents produced by a temperature gradient is ultimately limited by the intrinsic thermoelectric anisotropy and inhomogeneity of the material to be inspected. The probability of detection (POD) of a given material flaw is determined by the resulting signal-to-noise ratio rather than by the absolute magnitude of the signal itself. The strength of the magnetic field to be detected greatly depends on the physical nature of the host medium and dimensions of the imperfection. This paper presents experimental data for the magnetic field produced by thermoelectric currents around tin inclusions in different host medium such as 316LVM stainless steel and Ti-6Al-4V titanium alloy under external thermal excitation. The diameter of the inclusions and the lift-off distance varied from 0.39 to 3.175 mm and from 1 to 10 mm, respectively. A 0.6 °C/cm temperature gradient in the samples produced peak magnetic flux densities ranging from 0.1 to 280 nT, that was measured by a fluxgate magnetometer. The numerical results were found to be in good agreement with theoretical predictions and demonstrated that both property anisotropy and gradient in thermoelectric materials can significantly influence the induced thermoelectric currents and magnetic fields.

  18. La 1-x Ca x MnO 3 semiconducting nanostructures: morphology and thermoelectric properties.

    Science.gov (United States)

    Culebras, Mario; Torán, Raquel; Gómez, Clara M; Cantarero, Andrés

    2014-01-01

    Semiconducting metallic oxides, especially perosvkite materials, are great candidates for thermoelectric applications due to several advantages over traditionally metallic alloys such as low production costs and high chemical stability at high temperatures. Nanostructuration can be the key to develop highly efficient thermoelectric materials. In this work, La 1-x Ca x MnO 3 perosvkite nanostructures with Ca as a dopant have been synthesized by the hydrothermal method to be used in thermoelectric applications at room temperature. Several heat treatments have been made in all samples, leading to a change in their morphology and thermoelectric properties. The best thermoelectric efficiency has been obtained for a Ca content of x=0.5. The electrical conductivity and Seebeck coefficient are strongly related to the calcium content.

  19. Thermoelectric band engineering: The role of carrier scattering

    Science.gov (United States)

    Witkoske, Evan; Wang, Xufeng; Lundstrom, Mark; Askarpour, Vahid; Maassen, Jesse

    2017-11-01

    Complex electronic band structures, with multiple valleys or bands at the same or similar energies, can be beneficial for thermoelectric performance, but the advantages can be offset by inter-valley and inter-band scattering. In this paper, we demonstrate how first-principles band structures coupled with recently developed techniques for rigorous simulation of electron-phonon scattering provide the capabilities to realistically assess the benefits and trade-offs associated with these materials. We illustrate the approach using n-type silicon as a model material and show that intervalley scattering is strong. This example shows that the convergence of valleys and bands can improve thermoelectric performance, but the magnitude of the improvement depends sensitively on the relative strengths of intra- and inter-valley electron scattering. Because anisotropy of the band structure also plays an important role, a measure of the benefit of band anisotropy in the presence of strong intervalley scattering is presented.

  20. Interfacial reactions in thermoelectric modules

    KAUST Repository

    Wu, Hsin-jay; Wu, Albert T.; Wei, Pei-chun; Chen, Sinn-wen

    2018-01-01

    Engineering transport properties of thermoelectric (TE) materials leads to incessantly breakthroughs in the zT values. Nevertheless, modular design holds a key factor to advance the TE technology. Herein, we discuss the structures of TE module

  1. General Approach for Composite Thermoelectric Systems with Thermal Coupling: The Case of a Dual Thermoelectric Cooler

    Directory of Open Access Journals (Sweden)

    Cuautli Yanehowi Flores-Niño

    2015-06-01

    Full Text Available In this work, we show a general approach for inhomogeneous composite thermoelectric systems, and as an illustrative case, we consider a dual thermoelectric cooler. This composite cooler consists of two thermoelectric modules (TEMs connected thermally in parallel and electrically in series. Each TEM has different thermoelectric (TE properties, namely thermal conductance, electrical resistance and the Seebeck coefficient. The system is coupled by thermal conductances to heat reservoirs. The proposed approach consists of derivation of the dimensionless thermoelectric properties for the whole system. Thus, we obtain an equivalent figure of merit whose impact and meaning is discussed. We make use of dimensionless equations to study the impact of the thermal conductance matching on the cooling capacity and the coefficient of the performance of the system. The equivalent thermoelectric properties derived with our formalism include the external conductances and all intrinsic thermoelectric properties of each component of the system. Our proposed approach permits us changing the thermoelectric parameters of the TEMs and the working conditions of the composite system. Furthermore, our analysis shows the effect of the number of thermocouples on the system. These considerations are very useful for the design of thermoelectric composite systems. We reproduce the qualitative behavior of a commercial composite TEM connected electrically in series.

  2. Eco-friendly p-type Cu2SnS3 thermoelectric material: crystal structure and transport properties

    Science.gov (United States)

    Shen, Yawei; Li, Chao; Huang, Rong; Tian, Ruoming; Ye, Yang; Pan, Lin; Koumoto, Kunihito; Zhang, Ruizhi; Wan, Chunlei; Wang, Yifeng

    2016-01-01

    As a new eco-friendly thermoelectric material, copper tin sulfide (Cu2SnS3) ceramics were experimentally studied by Zn-doping. Excellent electrical transport properties were obtained by virtue of 3-dimensionally conductive network for holes, which are less affected by the coexistence of cubic and tetragonal phases that formed upon Zn subsitition for Sn; a highest power factors ~0.84 mW m−1 K−2 at 723 K was achieved in the 20% doped sample. Moreover, an ultralow lattice thermal conductivity close to theoretical minimum was observed in these samples, which could be related to the disordering of atoms in the coexisting cubic and tetragonal phases and the interfaces. Thanks to the phonon-glass-electron-crystal features, a maximum ZT ~ 0.58 was obtained at 723 K, which stands among the tops for sulfide thermoelectrics at the same temperature. PMID:27666524

  3. Enhanced thermoelectric power in two-dimensional transition metal dichalcogenide monolayers

    KAUST Repository

    Pu, Jiang

    2016-07-27

    The carrier-density-dependent conductance and thermoelectric properties of large-area MoS2 and WSe2 monolayers are simultaneously investigated using the electrolyte gating method. The sign of the thermoelectric power changes across the transistor off-state in the ambipolar WSe2 transistor as the majority carrier density switches from electron to hole. The thermopower and thermoelectric power factor of monolayer samples are one order of magnitude larger than that of bulk materials, and their carrier-density dependences exhibit a quantitative agreement with the semiclassical Mott relation based on the two-dimensional energy band structure, concluding the thermoelectric properties are enhanced by the low-dimensional effect.

  4. Phase transition enhanced thermoelectric figure-of-merit in copper chalcogenides

    Directory of Open Access Journals (Sweden)

    David R. Brown

    2013-11-01

    Full Text Available While thermoelectric materials can be used for solid state cooling, waste heat recovery, and solar electricity generation, low values of the thermoelectric figure of merit, zT, have led to an efficiency too low for widespread use. Thermoelectric effects are characterized by the Seebeck coefficient or thermopower, which is related to the entropy associated with charge transport. For example, coupling spin entropy with the presence of charge carriers has enabled the enhancement of zT in cobalt oxides. We demonstrate that the coupling of a continuous phase transition to carrier transport in Cu2Se over a broad (360–410 K temperature range results in a dramatic peak in thermopower, an increase in phonon and electron scattering, and a corresponding doubling of zT (to 0.7 at 406 K, and a similar but larger increase over a wider temperature range in the zT of Cu1.97Ag.03Se (almost 1.0 at 400 K. The use of structural entropy for enhanced thermopower could lead to new engineering approaches for thermoelectric materials with high zT and new green applications for thermoelectrics.

  5. Thermoelectric Generation Of Current – Theoretical And Experimental Analysis

    Directory of Open Access Journals (Sweden)

    Ruciński Adam

    2017-12-01

    Full Text Available This paper provides some information about thermoelectric technology. Some new materials with improved figures of merit are presented. These materials in Peltier modules make it possible to generate electric current thanks to a temperature difference. The paper indicates possible applications of thermoelectric modules as interesting tools for using various waste heat sources. Some zero-dimensional equations describing the conditions of electric power generation are given. Also, operating parameters of Peltier modules, such as voltage and electric current, are analyzed. The paper shows chosen characteristics of power generation parameters. Then, an experimental stand for ongoing research and experimental measurements are described. The authors consider the resistance of a receiver placed in the electric circuit with thermoelectric elements. Finally, both the analysis of experimental results and conclusions drawn from theoretical findings are presented. Voltage generation of about 1.5 to 2.5 V for the temperature difference from 65 to 85 K was observed when a bismuth telluride thermoelectric couple (traditionally used in cooling technology was used.

  6. Computational studies of novel thermoelectric materials

    Energy Technology Data Exchange (ETDEWEB)

    Singh, D J; Mazin, I I; Kim, S G; Nordstrom, L

    1997-07-01

    The thermoelectric properties of La-filled skutterdites and {beta}-Zn{sub 4}Sb{sub 3} are discussed from the point of view of their electronic structures. These are calculated from first principles within the local density approximation. The electronic structures are in turn used to determine transport related quantities, {beta}-Zn{sub 4}Sb{sub 3} is found to be metallic with a complex Fermi surface topology, which yields a non-trivial dependence of the Hall concentration on the band filling. Calculations of the variation with band filling are used to extract the carrier concentration from the experimental Hall number. At this band filling, which corresponds to 0.1 electrons per 22 atom unit cell, the authors calculate a Seebeck coefficient and temperature dependence in good agreement with the experimental value. The high Seebeck coefficients in a metallic material are remarkable, and arise because of the strong energy dependence of the Fermiology near the experimental band filling. Virtual crystal calculations for La(Fe,Co){sub 4}Sb{sub 12}. The valence band maximum occurs at the {Gamma} point and is due to a singly degenerate dispersive (Fe,Co)-Sb band, which by itself would not be favorable for TE. However, very flat transition metal derived bands occur in close proximity and become active as the doping level is increased, giving a non-trivial dependence of the properties on carrier concentration and explaining the favorable TE properties.

  7. Enhancement of Thermoelectric Properties of PEDOT:PSS and Tellurium-PEDOT:PSS Hybrid Composites by Simple Chemical Treatment

    Science.gov (United States)

    Jin Bae, Eun; Hun Kang, Young; Jang, Kwang-Suk; Yun Cho, Song

    2016-01-01

    The thermoelectric properties of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and tellurium-PEDOT:PSS (Te-PEDOT:PSS) hybrid composites were enhanced via simple chemical treatment. The performance of thermoelectric materials is determined by their electrical conductivity, thermal conductivity, and Seebeck coefficient. Significant enhancement of the electrical conductivity of PEDOT:PSS and Te-PEDOT:PSS hybrid composites from 787.99 and 11.01 to 4839.92 and 334.68 S cm-1, respectively was achieved by simple chemical treatment with H2SO4. The power factor of the developed materials could be effectively tuned over a very wide range depending on the concentration of the H2SO4 solution used in the chemical treatment. The power factors of the developed thermoelectric materials were optimized to 51.85 and 284 μW m-1 K-2, respectively, which represent an increase of four orders of magnitude relative to the corresponding parameters of the untreated thermoelectric materials. Using the Te-PEDOT:PSS hybrid composites, a flexible thermoelectric generator that could be embedded in textiles was fabricated by a printing process. This thermoelectric array generates a thermoelectric voltage of 2 mV using human body heat.

  8. High-Temperature High-Efficiency Solar Thermoelectric Generators

    Energy Technology Data Exchange (ETDEWEB)

    Baranowski, LL; Warren, EL; Toberer, ES

    2014-03-01

    Inspired by recent high-efficiency thermoelectric modules, we consider thermoelectrics for terrestrial applications in concentrated solar thermoelectric generators (STEGs). The STEG is modeled as two subsystems: a TEG, and a solar absorber that efficiently captures the concentrated sunlight and limits radiative losses from the system. The TEG subsystem is modeled using thermoelectric compatibility theory; this model does not constrain the material properties to be constant with temperature. Considering a three-stage TEG based on current record modules, this model suggests that 18% efficiency could be experimentally expected with a temperature gradient of 1000A degrees C to 100A degrees C. Achieving 15% overall STEG efficiency thus requires an absorber efficiency above 85%, and we consider two methods to achieve this: solar-selective absorbers and thermally insulating cavities. When the TEG and absorber subsystem models are combined, we expect that the STEG modeled here could achieve 15% efficiency with optical concentration between 250 and 300 suns.

  9. Finds of radioactive materials in Central Slovakia in 1996-1998

    International Nuclear Information System (INIS)

    Auxtova, L.; Durec, F.; Adamek, P.

    1998-01-01

    A brief report of finds of radioactive materials out of control in Central Slovakia during period 1996-1998 has been made in this paper. The reasons of the reported events are described if known and some recommendations on safety culture development and implementation have been given. (author)

  10. Synthesis and thermoelectric performance of a p-type Bi0.4Sb1.6Te3 material developed via mechanical alloying

    International Nuclear Information System (INIS)

    Jimenez, Sandra; Perez, Jose G.; Tritt, Terry M.; Zhu, Song; Sosa-Sanchez, Jose L.; Martinez-Juarez, Javier; López, Osvaldo

    2014-01-01

    Highlights: • This paper shows a Bi 1.6 Sb 0.4 Te 3 alloy prepared by MA-SPS process. • A ZT value of about 1.2–1.3 around 360 K was achieved for this compound. • The lower sintering process was carried out in a short time. • The resulting material has a very fine microstructure and high density. - Abstract: A p-type Bi 0.4 Sb 1.6 Te 3 thermoelectric compound was fabricated via mechanical alloying of bismuth, antimony and tellurium elemental powders as starting materials. The mechanically alloyed compositions were sintered through a spark-plasma sintering (SPS) process. The effect of the milling time was investigated. In order to characterize the powders obtained via mechanical alloying, X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS) analysis were used. The morphological evolution was studied by scanning electron microscopy (SEM). Results showed that the p-type Bi 0.4 Sb 1.6 Te 3 compound was formed after 2 h of milling. Further, the variation of milling time showed that the synthesized phase was stable. All the powders exhibit the same morphology albeit with slight differences. Measurements of the electrical resistivity, Seebeck coefficient and thermal conductivity were performed in the temperature range 300–520 K for the SPS samples. The resulting thermoelectric figure of merit ZT reaches a maximum of 1.2 at 360 K for the p-type bulk material with a 5 h milling time. This study demonstrates the possibility of preparing thermoelectric materials of high performance and short processing time

  11. Synthesis and characterization of new ceramic thermoelectrics implemented in a thermoelectric oxide module

    Czech Academy of Sciences Publication Activity Database

    Tomeš, P.; Robert, R.; Trottmann, M.; Bocher, L.; Aguirre, M.H.; Bitschi, A.; Hejtmánek, Jiří; Weidenkaff, A.

    2010-01-01

    Roč. 39, č. 9 (2010), 1696-1703 ISSN 0361-5235 Institutional research plan: CEZ:AV0Z10100521 Keywords : thermoelectric materials * perovskites * power generation * oxide ceramics * micro-IR camera measurement Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.421, year: 2010

  12. Thermoelectric powered wireless sensors for spent fuel monitoring

    International Nuclear Information System (INIS)

    Carstens, T.; Corradini, M.; Blanchard, J.; Ma, Z.

    2011-01-01

    This paper describes using thermoelectric generators to power wireless sensors to monitor spent nuclear fuel during dry-cask storage. OrigenArp was used to determine the decay heat of the spent fuel at different times during the service life of the dry-cask. The Engineering Equation Solver computer program modeled the temperatures inside the spent fuel storage facility during its service life. The temperature distribution in a thermoelectric generator and heat sink was calculated using the computer program Finite Element Heat Transfer. From these temperature distributions the power produced by the thermoelectric generator was determined as a function of the service life of the dry-cask. In addition, an estimation of the path loss experienced by the wireless signal can be made based on materials and thickness of the structure. Once the path loss is known, the transmission power and thermoelectric generator power requirements can be determined. This analysis estimates that a thermoelectric generator can produce enough power for a sensor to function and transmit data from inside the dry-cask throughout its service life. (authors)

  13. Enhanced low-temperature thermoelectrical properties of BiTeCl grown by topotactic method

    International Nuclear Information System (INIS)

    Jacimovic, J.; Mettan, X.; Pisoni, A.; Gaal, R.; Katrych, S.; Demko, L.; Akrap, A.; Forro, L.; Berger, H.; Bugnon, P.; Magrez, A.

    2014-01-01

    We developed a topotactic strategy to grow BiTeCl single crystals. Structural characterization by means of X-ray diffraction was performed, and the high crystallinity of the material was proven. Measurements of the thermoelectrical coefficients electrical resistivity, thermoelectric power and thermal conductivity show an enhanced room temperature power factor of 20 μW cm −1 K −2 . The high value of the figure of merit (ZT = 0.17) confirms that BiTeCl is a promising material for engineering in thermoelectric applications at low temperature

  14. Ambient growth of highly oriented Cu{sub 2}S dendrites of superior thermoelectric behaviour

    Energy Technology Data Exchange (ETDEWEB)

    Mulla, Rafiq; Rabinal, M.K., E-mail: mkrabinal@yahoo.com

    2017-03-01

    Highlights: • A simple and ambient route to synthesize highly oriented dendrites of copper sulfide is proposed. • Remarkable enhancement is observed in Seebeck coefficient by room temperature, solution phase doping. • High thermoelectric power factor is observed at room temperature, indicating promising behaviour. - Abstract: Low-cost, non-toxic and efficient material is an urgent need for the thermoelectric energy conversion. Here, a rapid and ambient chemical route has been developed to grow dense and highly oriented dendrites of copper sulfide (Cu{sub 2}S) on copper substrate in a very simple approach, these films are uniform and covered with dense nanosheets. Room temperature solution doping of copper ions is carried out to improve thermoelectric performance. The Seebeck coefficient increased from ∼100 to 415 μV K{sup −1} with a slight decrease in electrical conductivity, this gives a high power factor (S{sup 2}σ) of about ∼400 μW m{sup −1} K{sup −2}. The improved thermoelectric properties in these films are accounted for resonant energy level doping and high phonon scattering. Such films with improved thermoelectric behaviour can be promising materials for energy conversion. The earth abundant, low cost, non toxic with a good thermoelectric property makes copper sulfide as a promising thermoelectric material for future applications.

  15. Operational Readiness Review Plan for the Radioisotope Thermoelectric Generator Materials Production Tasks

    Science.gov (United States)

    Cooper, R. H.; Martin, M. M.; Riggs, C. R.; Beatty, R. L.; Ohriner, E. K.; Escher, R. N.

    1990-04-19

    In October 1989, a US shuttle lifted off from Cape Kennedy carrying the spacecraft Galileo on its mission to Jupiter. In November 1990, a second spacecraft, Ulysses, will be launched from Cape Kennedy with a mission to study the polar regions of the sun. The prime source of power for both spacecraft is a series of radioisotope thermoelectric generators (RTGs), which use plutonium oxide (plutonia) as a heat source. Several of the key components in this power system are required to ensure the safety of both the public and the environment and were manufactured at Oak Ridge National Laboratory (ORNL) in the 1980 to 1983 period. For these two missions, Martin Marietta Energy Systems, Inc. (Energy Systems), will provide an iridium alloy component used to contain the plutonia heat source and a carbon composite material that serves as a thermal insulator. ORNL alone will continue to fabricate the carbon composite material. Because of the importance to DOE that Energy Systems deliver these high quality components on time, performance of an Operational Readiness Review (ORR) of these manufacturing activities is necessary. Energy Systems Policy GP 24 entitled "Operational Readiness Process" describes the formal and comprehensive process by which appropriate Energy Systems activities are to be reviewed to ensure their readiness. This Energy System policy is aimed at reducing the risks associated with mission success and requires a management approved "readiness plan" to be issued. This document is the readiness plan for the RTG materials production tasks.

  16. Production and exploitation of thermoelectric air conditioning systems for vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Dudnik, Vladimir [Conditioner Ltd, Gagarin (Russian Federation); Skipidarov, Sergey [SCTB NORD, Moskau (Russian Federation); Rapp, Axel [Quick-Ohm Kupper und Co. GmbH, Wuppertal-Cronenberg (Germany)

    2011-07-01

    In the paper more than 10-year experience of thermoelectric devices batch manufacturing is described for the field of their obvious advantages. This field of application includes thermoelectric air conditioning systems which have shown their competitive advantage when used in vehicles of elevated vibration where compressor equipment application is difficult because of leakage of refrigerant. Energy characteristics of air conditioners for tractors, excavators, tanks, locomotive driver's cabins and cranes are described. Thermoelectric (TE) air conditioners mechanical test data as well as operation experience in vehicles are presented. It is shown that consumption of tellurium, which is a strategic component for thermoelectric materials manufacturing, may be lowered to 40 grams per 1 kW of cooling. (orig.)

  17. High thermoelectric power factor in two-dimensional crystals of Mo S2

    Science.gov (United States)

    Hippalgaonkar, Kedar; Wang, Ying; Ye, Yu; Qiu, Diana Y.; Zhu, Hanyu; Wang, Yuan; Moore, Joel; Louie, Steven G.; Zhang, Xiang

    2017-03-01

    The quest for high-efficiency heat-to-electricity conversion has been one of the major driving forces toward renewable energy production for the future. Efficient thermoelectric devices require high voltage generation from a temperature gradient and a large electrical conductivity while maintaining a low thermal conductivity. For a given thermal conductivity and temperature, the thermoelectric power factor is determined by the electronic structure of the material. Low dimensionality (1D and 2D) opens new routes to a high power factor due to the unique density of states (DOS) of confined electrons and holes. The 2D transition metal dichalcogenide (TMDC) semiconductors represent a new class of thermoelectric materials not only due to such confinement effects but especially due to their large effective masses and valley degeneracies. Here, we report a power factor of Mo S2 as large as 8.5 mW m-1K-2 at room temperature, which is among the highest measured in traditional, gapped thermoelectric materials. To obtain these high power factors, we perform thermoelectric measurements on few-layer Mo S2 in the metallic regime, which allows us to access the 2D DOS near the conduction band edge and exploit the effect of 2D confinement on electron scattering rates, resulting in a large Seebeck coefficient. The demonstrated high, electronically modulated power factor in 2D TMDCs holds promise for efficient thermoelectric energy conversion.

  18. Thermoelectric transport in rare-earth compounds

    International Nuclear Information System (INIS)

    Koehler, Ulrike

    2007-01-01

    This work focuses on the thermoelectric transport in rare-earth compounds. The measurements of the thermal conductivity, thermopower, and Nernst coefficient are supplemented by investigations of other quantities as magnetic susceptibility and specific heat. Chapter 2 provides an introduction to the relevant physical concepts. Section 1 of that chapter summarizes the characteristic properties of rare-earth systems; section 2 gives an overview on thermoelectric transport processes in magnetic fields. The applied experimental techniques as well as the new experimental setup are described in detail in Chapter 3. The experimental results are presented in Chapter 4-6, of which each concentrates on a different subject. In Chapter 4, various Eu clathrates and the skutterudite-like Ce 3 Rh 4 Sn 13 are presented, which have been investigated as potential thermoelectric materials for applications. Chapter 5 focusses on the study of the energy scales in the heavy-fermion series Lu 1-x Yb x Rh 2 Si 2 and Ce x La 1-x Ni 2 Ge 2 by means of thermopower investigations. Chapter 6 is dedicated to the thermoelectric transport properties of the correlated semimetal CeNiSn with special emphasis on the Nernst coefficient of this compound. (orig.)

  19. Lead telluride with increased mechanical stability for cylindrical thermoelectric generators; Bleitellurid mit erhoehter mechanischer Stabilitaet fuer zylindrische thermoelektrische Generatoren

    Energy Technology Data Exchange (ETDEWEB)

    Schmitz, Andreas

    2013-04-30

    The aim of this work is to improve the mechanical stability of lead telluride (PbTe), trying to vary its mechanical properties independently from its thermoelectric properties. Thus the influence of material preparation as well as different dopants on the mechanical and thermoelectric properties of lead telluride is being analysed. When using appropriately set process parameters, milling and sintering of lead telluride increases the material's hardness. With sintering temperatures exceeding 300 C stable material of high relative density can be achieved. Milling lead telluride generates lattice defects leading to a reduction of the material's charge carrier density. These defects can be reduced by increased sintering temperatures. Contamination of the powder due to the milling process leads to bloating during thermal cycling and thus reduced density of the sintered material. In addition to that, evaporation of tellurium at elevated temperatures causes instability of the material's thermoelectric properties. Based on the experimental results obtained in this work, the best thermoelectric and mechanical properties can be obtained by sintering coarse powders at around 400 C. Within this work a concept was developed to vary the mechanical properties of lead telluride via synthesis of PbTe with electrically nondoping elements, which thus may keep the thermoelectric properties unchanged. Therefore, the mechanical and thermoelectric properties of Pb{sub 1-x}Ca{sub x}Te were investigated. Doping pure PbTe with calcium causes a significant increase of the material's hardness while only slightly decreasing the charge carrier density and thus keeping the thermoelectric properties apart from a slight reduction of the electrical conductivity nearly unchanged. The abovementioned concept is proven using sodium doped lead telluride, as it is used for thermoelectric generators: The additional doping with calcium again increases the material's hardness while its thermoelectric

  20. Lead telluride with increased mechanical stability for cylindrical thermoelectric generators; Bleitellurid mit erhoehter mechanischer Stabilitaet fuer zylindrische thermoelektrische Generatoren

    Energy Technology Data Exchange (ETDEWEB)

    Schmitz, Andreas

    2013-04-30

    The aim of this work is to improve the mechanical stability of lead telluride (PbTe), trying to vary its mechanical properties independently from its thermoelectric properties. Thus the influence of material preparation as well as different dopants on the mechanical and thermoelectric properties of lead telluride is being analysed. When using appropriately set process parameters, milling and sintering of lead telluride increases the material's hardness. With sintering temperatures exceeding 300 C stable material of high relative density can be achieved. Milling lead telluride generates lattice defects leading to a reduction of the material's charge carrier density. These defects can be reduced by increased sintering temperatures. Contamination of the powder due to the milling process leads to bloating during thermal cycling and thus reduced density of the sintered material. In addition to that, evaporation of tellurium at elevated temperatures causes instability of the material's thermoelectric properties. Based on the experimental results obtained in this work, the best thermoelectric and mechanical properties can be obtained by sintering coarse powders at around 400 C. Within this work a concept was developed to vary the mechanical properties of lead telluride via synthesis of PbTe with electrically nondoping elements, which thus may keep the thermoelectric properties unchanged. Therefore, the mechanical and thermoelectric properties of Pb{sub 1-x}Ca{sub x}Te were investigated. Doping pure PbTe with calcium causes a significant increase of the material's hardness while only slightly decreasing the charge carrier density and thus keeping the thermoelectric properties apart from a slight reduction of the electrical conductivity nearly unchanged. The abovementioned concept is proven using sodium doped lead telluride, as it is used for thermoelectric generators: The additional doping with calcium again increases the material's hardness while

  1. Plasma synthesis of nanostructures for improved thermoelectric properties

    International Nuclear Information System (INIS)

    Petermann, Nils; Hecht, Christian; Schulz, Christof; Wiggers, Hartmut; Stein, Niklas; Schierning, Gabi; Theissmann, Ralf; Stoib, Benedikt; Brandt, Martin S

    2011-01-01

    The utilization of silicon-based materials for thermoelectrics is studied with respect to the synthesis and processing of doped silicon nanoparticles from gas phase plasma synthesis. It is found that plasma synthesis enables the formation of spherical, highly crystalline and soft-agglomerated materials. We discuss the requirements for the formation of dense sintered bodies, while keeping the crystallite size small. Small particles a few tens of nanometres and below that are easily achievable from plasma synthesis, and a weak surface oxidation, both lead to a pronounced sinter activity about 350 K below the temperature usually needed for the successful densification of silicon. The thermoelectric properties of our sintered materials are comparable to the best results found for nanocrystalline silicon prepared by methods other than plasma synthesis.

  2. Thermoelectric Power Factor Limit of a 1D Nanowire

    Science.gov (United States)

    Chen, I.-Ju; Burke, Adam; Svilans, Artis; Linke, Heiner; Thelander, Claes

    2018-04-01

    In the past decade, there has been significant interest in the potentially advantageous thermoelectric properties of one-dimensional (1D) nanowires, but it has been challenging to find high thermoelectric power factors based on 1D effects in practice. Here we point out that there is an upper limit to the thermoelectric power factor of nonballistic 1D nanowires, as a consequence of the recently established quantum bound of thermoelectric power output. We experimentally test this limit in quasiballistic InAs nanowires by extracting the maximum power factor of the first 1D subband through I -V characterization, finding that the measured maximum power factors conform to the theoretical limit. The established limit allows the prediction of the achievable power factor of a specific nanowire material system with 1D electronic transport based on the nanowire dimension and mean free path. The power factor of state-of-the-art semiconductor nanowires with small cross section and high crystal quality can be expected to be highly competitive (on the order of mW /m K2 ) at low temperatures. However, they have no clear advantage over bulk materials at, or above, room temperature.

  3. Effect of current on the microstructure and performance of (Bi2Te3)0.2(Sb2Te3)0.8 thermoelectric material via field activated and pressure assisted sintering

    International Nuclear Information System (INIS)

    Chen Ruixue; Meng Qingsen; Fan Wenhao; Wang Zhong

    2011-01-01

    (Bi 2 Te 3 ) 0.2 (Sb 2 Te 3 ) 0.8 thermoelectric material was sintered via a field activated and pressure assisted sintering (FAPAS) process. By applying different current intensity (0, 60, 320 A/cm 2 ) in the sintering process, the effects of electric current on the microstructure and thermoelectric performance were investigated. This demonstrated that the application of electric current in the sintering process could significantly improve the uniformity and density of (Bi 2 Te 3 ) 0.2 (Sb 2 Te 3 ) 0.8 samples. When the current intensity was raised to 320 A/cm 2 , the preferred orientation of grains was observed. Moreover, positive effects on the thermoelectric performance of applying electric current in the sintering process were also confirmed. An increase of 0.02 and 0.11 in the maximum figure of merit ZT value could be acquired by applying current of 60 and 320 A/cm 2 , respectively. (semiconductor materials)

  4. Effect of spark plasma sintering conditions on the thermoelectric properties of (Bi{sub 0.25}Sb{sub 0.75}){sub 2}Te{sub 3} alloys

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Sang-Soon [Center for Electronic Materials, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Department of Materials Science and Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of); Kim, Ju-Heon [High Temp. Energy Materials Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Kwon, Beomjin; Kim, Seong Keun [Center for Electronic Materials, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Park, Hyung-Ho [Department of Materials Science and Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of); Lee, Ki-Suk; Baik, Jeong Min [School of Materials and Science Engineering, UNIST, Ulsan 689-798 (Korea, Republic of); KIST-UNIST Ulsan Center for Convergent Materials, UNIST, Ulsan 689-798 (Korea, Republic of); Choi, Won Jun [Center for Opto-Electronic Materials and Devices, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Kim, Dong-Ik [High Temp. Energy Materials Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Hyun, Dow-Bin; Kim, Jin-Sang [Center for Electronic Materials, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Baek, Seung-Hyub, E-mail: shbaek77@kist.re.kr [Center for Electronic Materials, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); KIST-UNIST Ulsan Center for Convergent Materials, UNIST, Ulsan 689-798 (Korea, Republic of); Department of Nanomaterials Science and Technology, Korea University of Science and Technology, Daejeon, 305-333 (Korea, Republic of)

    2016-09-05

    As a field-assisted technique, spark plasma sintering (SPS) enables densification of specimens in a very short period of time compared to other sintering techniques. For high performance thermoelectric material synthesis, SPS is widely used to fabricate nanograin-structured thermoelectric materials by rapidly densifying the nanopowders suppressing grain growth. However, the microstructural evolution behavior of thermoelectric materials by SPS, another important process during sintering, has been rarely studied. Here, we explore SPS as a tool to control the microstructure by long-time SPS. Using p-type (Bi{sub 0.25}Sb{sub 0.75}){sub 2}Te{sub 3} thermoelectric materials as a model system, we systematically vary SPS temperature and time to understand the correlations between SPS conditions, microstructural evolution, and the thermoelectric properties. Our results show that the relatively low eutectic temperature (∼420 °C) and the existence of volatile tellurium (Te) are critical factors to determine both microstructure and thermoelectric property. In the liquid-phase sintering regime, rapid evaporation of Te leads to a strong dependence of thermoelectric property on SPS time. On the other hand, in the solid-phase sintering regime, there is a weak dependence on SPS time. The optimum thermoelectric figure-of-merit (Z) of 2.93 × 10{sup −3}/K is achieved by SPS at 500 °C for 30 min. Our results will provide an insight on the optimization of SPS conditions for materials containing volatile elements with low eutectic temperature. - Highlights: • Spark plasma sintering (SPS) is used to synthesize the thermoelectric (Bi{sub 0.25}Sb{sub 0.75}){sub 2}Te{sub 3}. • Liquid phase and volatile element are a key for the microstructure and thermoelectric property. • Thermoelectric figure-of-merit of 2.9 × 10{sup −3}/K is achieved at 500 °C for 30 min.

  5. Impact of energy filtering and carrier localization on the thermoelectric properties of granular semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Narducci, Dario, E-mail: dario.narducci@unimib.it [Department of Materials Science, University of Milano Bicocca, via Cozzi 53, 20125 Milano (Italy); Consorzio DeltaTi Research (Italy); Selezneva, Ekaterina [Department of Materials Science, University of Milano Bicocca, via Cozzi 53, 20125 Milano (Italy); Cerofolini, Gianfranco [Department of Materials Science, University of Milano Bicocca, via Cozzi 53, 20125 Milano (Italy); Consorzio DeltaTi Research (Italy); Frabboni, Stefano; Ottaviani, Giampiero [Department of Physics, University of Modena and Reggio Emilia, via Campi 213, 41100 Modena (Italy)

    2012-09-15

    Energy filtering has been widely considered as a suitable tool to increase the thermoelectric performances of several classes of materials. In its essence, energy filtering provides a way to increase the Seebeck coefficient by introducing a strongly energy-dependent scattering mechanism. Under certain conditions, however, potential barriers may lead to carrier localization, that may also affect the thermoelectric properties of a material. A model is proposed, actually showing that randomly distributed potential barriers (as those found, e.g., in polycrystalline films) may lead to the simultaneous occurrence of energy filtering and carrier localization. Localization is shown to cause a decrease of the actual carrier density that, along with the quantum tunneling of carriers, may result in an unexpected increase of the power factor with the doping level. The model is corroborated toward experimental data gathered by several authors on degenerate polycrystalline silicon and lead telluride. - Graphical abstract: In heavily doped semiconductors potential barriers may lead to both carrier energy filtering and localization. This may lead to an enhancement of the thermoelectric properties of the material, resulting in an unexpected increase of the power factor with the doping level. Highlights: Black-Right-Pointing-Pointer Potential barriers are shown to lead to carrier localization in thermoelectric materials. Black-Right-Pointing-Pointer Evidence is put forward of the formation of a mobility edge. Black-Right-Pointing-Pointer Energy filtering and localization may explain the enhancement of power factor in degenerate semiconductors.

  6. Criteria for extending the operation periods of thermoelectric converters based on IV-VI compounds

    Energy Technology Data Exchange (ETDEWEB)

    Sadia, Yatir, E-mail: yatttir@yahoo.com [Department of Materials Engineering, Ben-Gurion University of the Negev, Beer-Sheva (Israel); Ohaion-Raz, Tsion [Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva (Israel); Ben-Yehuda, Ohad; Korngold, Meidad; Gelbstein, Yaniv [Department of Materials Engineering, Ben-Gurion University of the Negev, Beer-Sheva (Israel)

    2016-09-15

    The recent energy demands affected by the dilution of conventional energy resources and the growing awareness of environmental considerations, had positioned the research of renewable energy conversion methods in general and of thermoelectric direct conversion of thermal into electrical energies in particular, in the forefront of the currently active applicative sciences. IV-VI thermoelectric compounds (e.g. GeTe, PbTe and SnTe) and their alloys comprise some of the most efficient thermoelectric compositions ever reported. Yet a proper utilization of such materials in practical thermoelectric devices, still requires an overcoming the so-called technological “valley of death”, including among others, transport properties' degradation, due to sublimation of volatile Te rich species, while being subjected to elevated temperatures for long periods of time. In an attempt to establish practical operation criteria for extending the operation periods of such thermoelectric converters, it is currently shown based on thermal gravimetric and metallurgical considerations that such harmful sublimation can be practically bridged over by limiting the maximal operating temperatures to the 410–430 °C range for GeTe rich alloys and to 510–530 °C for PbTe and SnTe rich alloys, depending of the thermoelectric leg's diameter. - Graphical abstract: Evaporation rate in the GeTe and PbTe system showing the measured evaporation rates and the maximal operating temperatures for different compositions. In addition, the microstructure after evaporation is shown for PbTe, TAGS-85, and doped Pb{sub 0.13}Ge{sub 087}Te. Display Omitted - Highlights: • Evaporation rates of GeTe and PbTe based thermoelectric compounds were determined. • A criterion for their maximum operating temperature was established. • The materials showed phase separations and off-stoichiometry compositions.

  7. Potential thermoelectric material open framework Si24 from a first-principles study

    International Nuclear Information System (INIS)

    Ouyang, Tao; Zhang, Pei; Xiao, Huaping; Tang, Chao; Li, Jin; He, Chaoyu; Zhong, Jianxin

    2017-01-01

    Open framework Si 24 is a new synthesis cage-like silicon allotrope with a quasi-direct bandgap and predicted to exhibit outstanding adsorption efficiency, foreshowing the potential applications in the photovoltaic community. In this paper, the thermoelectric property of such new Si structures is investigated by combining first-principles calculation and semiclassical Boltzmann transport theory. The calculations show that the Si 24 possesses a superb Seebeck coefficient, and obviously anisotropic electronic conductivity. Owing to more energy extremums existing in the conduction band region, the power factor of Si 24 in the n-type doping is always better than that in p-type samples. Anisotropic phonon transport property is observed as well in Si 24 with average lattice thermal conductivity of 45.35 W m −1 K −1 at room temperature. Based on the electron relaxation time estimated from the experiment, the thermoelectric figure of merit of Si 24 is found to be as high as 0.69 (n-type doping at 700 K) and 0.51 (p-type doping at 700 K) along the xx crystal direction, which is about two orders of magnitude larger than that of diamond Si ( d -Si). The findings presented in this work shed light on the thermoelectric performance of Si 24 and qualify that such new Si allotrope is a promising platform for achieving the recombination of photovoltaic and thermoelectric technologies together. (paper)

  8. Filled skutterudite antimonides: Validation of the electron-crystal phonon-glass approach to new thermoelectric materials

    Energy Technology Data Exchange (ETDEWEB)

    Mandrus, D; Sales, B C; Keppens, V [and others

    1997-07-01

    After a brief review of the transport and thermoelectric properties of filled skutterudite antimonides, the authors present resonant ultrasound, specific heat, and inelastic neutron scattering results that establish the existence of two low-energy vibrational modes in the filled skutterudite LaFe{sub 3}CoSb{sub 12}. It is likely that at least one of these modes represents the localized, incoherent vibrations of the La ion in an oversized atomic cage. These results support the usefulness of weakly bound, rattling ions for the improvement of thermoelectric performance.

  9. Thermoelectrode for thermoelectric converter

    International Nuclear Information System (INIS)

    Bodiul, Pavel; Bondarciuc, Nicolae; Ghitu, Dumitru; Nikolaeva, Albina; Konopko, Leonid; Turcan, Ana

    2008-01-01

    The invention relates to the electronic engneering and can be used for manufacturing of thermoelectrodes for thermoelectric converters. The thermoelectrode is made of semiconductor anisotropic material in the form of thread in glass insulation. At the same timer, the thread is made of stannum-doped tellurium in the ratio of 0.1...3 at.%.

  10. Quasi-two-dimensional thermoelectricity in SnSe

    Science.gov (United States)

    Tayari, V.; Senkovskiy, B. V.; Rybkovskiy, D.; Ehlen, N.; Fedorov, A.; Chen, C.-Y.; Avila, J.; Asensio, M.; Perucchi, A.; di Pietro, P.; Yashina, L.; Fakih, I.; Hemsworth, N.; Petrescu, M.; Gervais, G.; Grüneis, A.; Szkopek, T.

    2018-01-01

    Stannous selenide is a layered semiconductor that is a polar analog of black phosphorus and of great interest as a thermoelectric material. Unusually, hole doped SnSe supports a large Seebeck coefficient at high conductivity, which has not been explained to date. Angle-resolved photoemission spectroscopy, optical reflection spectroscopy, and magnetotransport measurements reveal a multiple-valley valence-band structure and a quasi-two-dimensional dispersion, realizing a Hicks-Dresselhaus thermoelectric contributing to the high Seebeck coefficient at high carrier density. We further demonstrate that the hole accumulation layer in exfoliated SnSe transistors exhibits a field effect mobility of up to 250 cm2/V s at T =1.3 K . SnSe is thus found to be a high-quality quasi-two-dimensional semiconductor ideal for thermoelectric applications.

  11. Contrastive thermoelectric properties of strained SnSe crystals from the first-principles calculations

    Science.gov (United States)

    Tang, Yu; Cheng, Feng; Li, Decong; Deng, Shuping; Chen, Zhong; Sun, Luqi; Liu, Wenting; Shen, Lanxian; Deng, Shukang

    2018-06-01

    SnSe is a promising thermoelectric material with a record high dimensionless figure of merit ZT at high temperature ∼923 K. However, the ZT values for low-Temperature Pnma phase SnSe are just 0.1-0.9. Here, we use First-principle combine with Boltzmann transport theory methods to study the effect of tensile and compressible strain on the thermoelectric transport properties. The power factor of SnSe with -4% strain have a large boost along b and c directions of 7.7 and 3.9 μW cm-1 K-2, respectively, which are 2.5 and 2 times as large as those pristine SnSe. The charge density distributions reveal that the overlap of wave function has significant change due to the changed bond lengths and bond angles under different strain, which lead to the change of band gap and band dispersion. Our work provides a new effective strategy to enhance the thermoelectric properties of materials.

  12. High Temperature Thermoelectric Materials for Waste Heat Regeneration

    Science.gov (United States)

    2013-01-01

    ADDRESS. 1. REPORT DATE (DD-MM-YYYY) January 2013 2. REPORT TYPE Final 3. DATES COVERED (From - To) 4. TITLE AND SUBTITLE High Temperature...National Aeronautics and Space Administration’s (NASA) deep space explorations, which use radioisotope thermoelectric generators (RTGs) to produce...their octahedral voids (shown in figure 10a) with large rare- earth atoms to reduce their lattice conductivity (20). Ions can also be inserted to

  13. Glances on the year 1998. Energies and raw materials

    International Nuclear Information System (INIS)

    1999-01-01

    This report summarizes 14 key-topics of the year 1998 in relation with the French energy and economic policy: the new start-up of energy mastery; the nuclear industry between passion and reason; the labour inspection in nuclear power plants; the law project for the modernizing and development of the electric power public utility; the main gas transportation systems; the future of Gardanne's mining basin; the raw materials in the upheaval; the French refining activity after the Auto-Oil directive; the oil company fusions; the priorities in petroleum technology research; the policy of automotive fuels distribution; the energy in regions; the mining activity in New Caledonia; the end of the BRGM-Normandy partnership. A calendar of remarkable facts is given at the end. (J.S.)

  14. Bulk Thermoelectric Materials Reinforced with SiC Whiskers

    Science.gov (United States)

    Akao, Takahiro; Fujiwara, Yuya; Tarui, Yuki; Onda, Tetsuhiko; Chen, Zhong-Chun

    2014-06-01

    SiC whiskers have been incorporated into Zn4Sb3 compound as reinforcements to overcome its extremely brittle nature. The bulk samples were prepared by either hot-extrusion or hot-pressing techniques. The obtained products containing 1 vol.% to 5 vol.% SiC whiskers were confirmed to exhibit sound appearance, high density, and fine-grained microstructure. Mechanical properties such as the hardness and fracture resistance were improved by the addition of SiC whiskers, as a result of dispersion strengthening and microstructural refinement induced by a pinning effect. Furthermore, crack deflection and/or bridging/pullout mechanisms are invoked by the whiskers. Regarding the thermoelectric properties, the Seebeck coefficient and electrical resistivity values comparable to those of the pure compound are retained over the entire range of added whisker amount. However, the thermal conductivity becomes large with increasing amount of SiC whiskers because of the much higher conductivity of SiC relative to the Zn4Sb3 matrix. This results in a remarkable degradation of the dimensionless figure of merit in the samples with addition of SiC whiskers. Therefore, the optimum amount of SiC whiskers in the Zn4Sb3 matrix should be determined by balancing the mechanical properties and thermoelectric performance.

  15. Influence of high energy β-radiation on thermoelectric performance of filled skutterudites compounds

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jikun, E-mail: jikunchen@seas.harvard.edu [CAS Key Laboratory of Materials for Energy Conversion, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Zha, Hao [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); Key Laboratory of Particle & Radiation Imaging, Tsinghua University, Ministry of Education, Beijing (China); Xia, Xugui; Qiu, Pengfei; Li, Yulong [CAS Key Laboratory of Materials for Energy Conversion, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Wang, Chuanjing; Han, Yunsheng [Nuctech Company Limited, Beijing (China); Shi, Xun; Chen, Lidong [CAS Key Laboratory of Materials for Energy Conversion, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Jin, Qingxiu [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); Key Laboratory of Particle & Radiation Imaging, Tsinghua University, Ministry of Education, Beijing (China); Chen, Huaibi, E-mail: chenhb@mail.tsinghua.edu.cn [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); Key Laboratory of Particle & Radiation Imaging, Tsinghua University, Ministry of Education, Beijing (China)

    2015-08-15

    Highlights: • Impact by MeV β-rays irradiation on skutterudite TE material was investigated. • Monte-Carlo simulation is used to simulate the deposited energy irradiations. • The high deposited energy does not change the TE performance. • The light irradiation does not show a significant impact on TE materials. - Abstract: The influence of MeV β-rays irradiation on the thermoelectric performance of n-type filled skutterudite material has been investigated using an electron accelerator. Using a Monte-Carlo simulation base on Fluka code, the deposited energy in the sample material from the irradiation is estimated, which shows a large power deposited around 50 W/mm. Nevertheless, the thermoelectric performances of the filled skutterudite samples are compared before and after irradiations. It indicates that the thermoelectric material will not be easily jeopardized by ‘light’ irradiations with energy lower than MeV range.

  16. Influence of high energy β-radiation on thermoelectric performance of filled skutterudites compounds

    International Nuclear Information System (INIS)

    Chen, Jikun; Zha, Hao; Xia, Xugui; Qiu, Pengfei; Li, Yulong; Wang, Chuanjing; Han, Yunsheng; Shi, Xun; Chen, Lidong; Jin, Qingxiu; Chen, Huaibi

    2015-01-01

    Highlights: • Impact by MeV β-rays irradiation on skutterudite TE material was investigated. • Monte-Carlo simulation is used to simulate the deposited energy irradiations. • The high deposited energy does not change the TE performance. • The light irradiation does not show a significant impact on TE materials. - Abstract: The influence of MeV β-rays irradiation on the thermoelectric performance of n-type filled skutterudite material has been investigated using an electron accelerator. Using a Monte-Carlo simulation base on Fluka code, the deposited energy in the sample material from the irradiation is estimated, which shows a large power deposited around 50 W/mm. Nevertheless, the thermoelectric performances of the filled skutterudite samples are compared before and after irradiations. It indicates that the thermoelectric material will not be easily jeopardized by ‘light’ irradiations with energy lower than MeV range

  17. High-temperature thermoelectric behavior of lead telluride

    Indian Academy of Sciences (India)

    The central problem in thermoelectric material research is the selection of ... temperature range (400–1000 K), and bismuth telluride-based materials .... parent from the results that band non-parabolicity has a significant effect on the .... M P Singh thankfully acknowledges financial assistance from the Council of Scien-.

  18. Lead Telluride Doped with Au as a Very Promising Material for Thermoelectric Applications

    Directory of Open Access Journals (Sweden)

    Pantelija M. Nikolic

    2015-01-01

    Full Text Available PbTe single crystals doped with monovalent Au or Cu were grown using the Bridgman method. Far infrared reflectivity spectra were measured at room temperature for all samples and plasma minima were registered. These experimental spectra were numerically analyzed and optical parameters were calculated. All the samples of PbTe doped with Au or Cu were of the “n” type. The properties of these compositions were analyzed and compared with PbTe containing other dopants. The samples of PbTe doped with only 3.3 at% Au were the best among the PbTe + Au samples having the lowest plasma frequency and the highest mobility of free carriers-electrons, while PbTe doped with Cu was the opposite. Samples with the lowest Cu concentration of 0.23 at% Cu had the best properties. Thermal diffusivity and electronic transport properties of the same PbTe doped samples were also investigated using a photoacoustic (PA method with the transmission detection configuration. The results obtained with the far infrared and photoacoustic characterization of PbTe doped samples were compared and discussed. Both methods confirmed that when PbTe was doped with 3.3 at% Au, thermoelectric and electrical properties of this doped semiconductor were both significantly improved, so Au as a dopant in PbTe could be used as a new high quality thermoelectric material.

  19. Magnéli oxides as promising n-type thermoelectrics

    Directory of Open Access Journals (Sweden)

    Gregor Kieslich

    2014-10-01

    Full Text Available The discovery of a large thermopower in cobalt oxides in 1997 lead to a surge of interest in oxides for thermoelectric application. Whereas conversion efficiencies of p-type oxides can compete with non-oxide materials, n-type oxides show significantly lower thermoelectric performances. In this context so-called Magnéli oxides have recently gained attention as promising n-type thermoelectrics. A combination of crystallographic shear and intrinsic disorder lead to relatively low thermal conductivities and metallic-like electrical conductivities in Magnéli oxides. Current peak-zT values of 0.3 around 1100 K for titanium and tungsten Magnéli oxides are encouraging for future research. Here, we put Magnéli oxides into context of n-type oxide thermoelectrics and give a perspective where future research can bring us.

  20. Alkaline earth filled nickel skutterudite antimonide thermoelectrics

    Science.gov (United States)

    Singh, David Joseph

    2013-07-16

    A thermoelectric material including a body centered cubic filled skutterudite having the formula A.sub.xFe.sub.yNi.sub.zSb.sub.12, where A is an alkaline earth element, x is no more than approximately 1.0, and the sum of y and z is approximately equal to 4.0. The alkaline earth element includes guest atoms selected from the group consisting of Be, Mb, Ca, Sr, Ba, Ra and combinations thereof. The filled skutterudite is shown to have properties suitable for a wide variety of thermoelectric applications.

  1. Modeling a Thermoelectric Generator Applied to Diesel Automotive Heat Recovery

    Science.gov (United States)

    Espinosa, N.; Lazard, M.; Aixala, L.; Scherrer, H.

    2010-09-01

    Thermoelectric generators (TEGs) are outstanding devices for automotive waste heat recovery. Their packaging, lack of moving parts, and direct heat to electrical conversion are the main benefits. Usually, TEGs are modeled with a constant hot-source temperature. However, energy in exhaust gases is limited, thus leading to a temperature decrease as heat is recovered. Therefore thermoelectric properties change along the TEG, affecting performance. A thermoelectric generator composed of Mg2Si/Zn4Sb3 for high temperatures followed by Bi2Te3 for low temperatures has been modeled using engineering equation solver (EES) software. The model uses the finite-difference method with a strip-fins convective heat transfer coefficient. It has been validated on a commercial module with well-known properties. The thermoelectric connection and the number of thermoelements have been addressed as well as the optimum proportion of high-temperature material for a given thermoelectric heat exchanger. TEG output power has been estimated for a typical commercial vehicle at 90°C coolant temperature.

  2. Thermoelectric Response in Single Quintuple Layer Bi2Te3

    KAUST Repository

    Sharma, S.

    2016-10-05

    Because Bi2Te3 belongs to the most important thermoelectric materials, the successful exfoliation of a single quintuple layer has opened access to an interesting two-dimensional material. For this reason, we study the thermoelectric properties of single quintuple layer Bi2Te3 by considering both the electron and phonon transport. On the basis of first-principles density functional theory, the electronic and phononic contributions are calculated by solving Boltzmann transport equations. The dependence of the lattice thermal conductivity on the phonon mean free path is evaluated along with the contributions of the acoustic and optical branches. We find that the thermoelectric response is significantly better for p- than for n-doping. By optimizing the carrier concentration, at 300 K, a ZT value of 0.77 is achieved, which increases to 2.42 at 700 K.

  3. Correlation between defect transition levels and thermoelectric operational temperature of doped CrSi2

    Science.gov (United States)

    Singh, Abhishek; Pandey, Tribhuwan

    2014-03-01

    The performance of a thermoelectric material is quantified by figure of merit ZT. The challenge in achieving high ZT value requires simultaneously high thermopower, high electrical conductivity and low thermal conductivity at optimal carrier concentration. So far doping is the most versatile approach used for modifying thermoelectric properties. Previous studies have shown that doping can significantly improve the thermoelectric performance, however the tuning the operating temperature of a thermoelectric device is a main issue. Using first principles density functional theory, we report for CrSi2, a linear relationship between thermodynamic charge state transition levels of defects and temperature at which thermopower peaks. We show for doped CrSi2 that the peak of thermopower occurs at the temperature Tm, which corresponds to the position of defect transition level. Therefore, by modifying the defect transition level, a thermoelectric material with a given operational temperature can be designed. The authors thankfully acknowledge support from ADA under NpMASS.

  4. US/Russian program in materials protection, control and accounting at the RRC Kurchatov Institute: 1997--1998

    International Nuclear Information System (INIS)

    Sukhoruchkin, V.; Rumyantsev, A.; Shmelev, V.

    1998-01-01

    Six US Department of Energy Laboratories are carrying out a program of cooperation with the Russian Research Center Kurchatov Institute to improve nuclear material protection, control and accounting (MPC and A) at Kurchatov. In 1997--1998 the primary thrust of this program has been directed to Building 106, which houses a number of test reactors and critical facilities. Substantial improvements in physical protection, upgrades in the physical inventory taking procedures, installation of equipment for the computerized materials accounting system, and installation of nuclear material portal monitors and neutron-based measurement equipment are being carried out at this facility. Software for the computerized accounting system, named KI-MACS, has been developed at Kurchatov and the system has been fully integrated with the bar code printing and reading equipment, electronic scales, and nondestructive assay equipment provided under this program. Additional 1997--1998 activities at Kurchatov include continuation of a tamper indicating device program, vulnerability assessments of several facilities, hosting of a Russian-American Workshop on Fissile Material Control and Accountability at Critical Facilities, and the development of accounting procedures for transfers of nuclear materials between material balance areas

  5. Direct evidence of strong local ferroelectric ordering in a thermoelectric semiconductor

    Energy Technology Data Exchange (ETDEWEB)

    Aggarwal, Leena; Sekhon, Jagmeet S.; Arora, Ashima; Sheet, Goutam, E-mail: goutam@iisermohali.ac.in [Department of Physical Sciences, Indian Institute of Science Education and Research Mohali (IISER M), Sector 81, S. A. S. Nagar, Manauli PO-140306 (India); Guin, Satya N.; Negi, Devendra S.; Datta, Ranjan; Biswas, Kanishka, E-mail: kanishka@jncasr.ac.in [New Chemistry Unit and International Centre for Materials Science, Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Jakkur, Bangalore 560064 (India)

    2014-09-15

    It is thought that the proposed new family of multi-functional materials, namely, the ferroelectric thermoelectrics may exhibit enhanced functionalities due to the coupling of the thermoelectric parameters with ferroelectric polarization in solids. Therefore, the ferroelectric thermoelectrics are expected to be of immense technological and fundamental significance. As a first step towards this direction, it is most important to identify the existing high performance thermoelectric materials exhibiting ferroelectricity. Herein, through the direct measurement of local polarization switching, we show that the recently discovered thermoelectric semiconductor AgSbSe{sub 2} has local ferroelectric ordering. Using piezo-response force microscopy, we demonstrate the existence of nanometer scale ferroelectric domains that can be switched by external electric field. These observations are intriguing as AgSbSe{sub 2} crystalizes in cubic rock-salt structure with centro-symmetric space group (Fm–3m), and therefore, no ferroelectricity is expected. However, from high resolution transmission electron microscopy measurement, we found the evidence of local superstructure formation which, we believe, leads to local distortion of the centro-symmetric arrangement in AgSbSe{sub 2} and gives rise to the observed ferroelectricity. Stereochemically active 5S{sup 2} lone-pair of Sb may also give rise to local structural distortion thereby creating ferroelectricity in AgSbSe{sub 2}.

  6. Thermoelectric transport in rare-earth compounds

    Energy Technology Data Exchange (ETDEWEB)

    Koehler, Ulrike

    2007-07-01

    This work focuses on the thermoelectric transport in rare-earth compounds. The measurements of the thermal conductivity, thermopower, and Nernst coefficient are supplemented by investigations of other quantities as magnetic susceptibility and specific heat. Chapter 2 provides an introduction to the relevant physical concepts. Section 1 of that chapter summarizes the characteristic properties of rare-earth systems; section 2 gives an overview on thermoelectric transport processes in magnetic fields. The applied experimental techniques as well as the new experimental setup are described in detail in Chapter 3. The experimental results are presented in Chapter 4-6, of which each concentrates on a different subject. In Chapter 4, various Eu clathrates and the skutterudite-like Ce{sub 3}Rh{sub 4}Sn{sub 13} are presented, which have been investigated as potential thermoelectric materials for applications. Chapter 5 focusses on the study of the energy scales in the heavy-fermion series Lu{sub 1-x}Yb{sub x}Rh{sub 2}Si{sub 2} and Ce{sub x}La{sub 1-x}Ni{sub 2}Ge{sub 2} by means of thermopower investigations. Chapter 6 is dedicated to the thermoelectric transport properties of the correlated semimetal CeNiSn with special emphasis on the Nernst coefficient of this compound. (orig.)

  7. Microstructure-lattice thermal conductivity correlation in nanostructured PbTe{sub 0.7}S{sub 0.3} thermoelectric materials

    Energy Technology Data Exchange (ETDEWEB)

    He, Jiaqing [Department of Materials Science and Engineering, Northwestern University Evanston, IL (United States); Department of Chemistry, Northwestern University Evanston, IL (United States); Girard, Steven N [Department of Chemistry, Northwestern University Evanston, IL (United States); Kanatzidis, Mercouri G [Department of Chemistry, Northwestern University Evanston, IL (United States); Materials Science Division Argonne, National Laboratory Argonne, IL (United States); Dravid, Vinayak P [Department of Materials Science and Engineering, Northwestern University Evanston, IL (United States)

    2010-03-09

    The reduction of thermal conductivity, and a comprehensive understanding of the microstructural constituents that cause this reduction, represent some of the important challenges for the further development of thermoelectric materials with improved figure of merit. Model PbTe-based thermoelectric materials that exhibit very low lattice thermal conductivity have been chosen for this microstructure-thermal conductivity correlation study. The nominal PbTe{sub 0.7}S{sub 0.3} composition spinodally decomposes into two phases: PbTe and PbS. Orderly misfit dislocations, incomplete relaxed strain, and structure-modulated contrast rather than composition-modulated contrast are observed at the boundaries between the two phases. Furthermore, the samples also contain regularly shaped nanometer-scale precipitates. The theoretical calculations of the lattice thermal conductivity of the PbTe{sub 0.7}S{sub 0.3} material, based on transmission electron microscopy observations, closely aligns with experimental measurements of the thermal conductivity of a very low value, {proportional_to}0.8 W m{sup -1} K{sup -1} at room temperature, approximately 35% and 30% of the value of the lattice thermal conductivity of either PbTe and PbS, respectively. It is shown that phase boundaries, interfacial dislocations, and nanometer-scale precipitates play an important role in enhancing phonon scattering and, therefore, in reducing the lattice thermal conductivity. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  8. Discussion on the electrical and thermoelectrical properties of amorphous In-Sb-Te Films

    Energy Technology Data Exchange (ETDEWEB)

    Aly, K.A. [University of Jeddah, Physics Department, Faculty of Science and Arts, Khulais, Jeddah (Saudi Arabia); Al-Azhar University, Assiut Branch, Physics Department, Faculty of Science, Asyut (Egypt); Saddeek, Y. [Al-Azhar University, Assiut Branch, Physics Department, Faculty of Science, Asyut (Egypt); Dahshan, A. [Port Said University, Department of Physics, Faculty of Science, Port Said (Egypt); King Khalid University, Department of Physics, Faculty of Science for Girls, Abha (Saudi Arabia)

    2016-03-15

    Different compositions of (In{sub 0.5}Sb{sub 0.5}){sub 1-x}Te{sub x} (0.50 ≤ x ≤ 0.65) thin films were prepared by thermal evaporated technique, onto pre-cleaned glass substrates at ∝298 K. Both dark electrical resistivity (ρ) and thermoelectric power (S) were measured in the temperature range 300-420 K. The concentration of the free carriers is obtained from DC conductivity and thermoelectric power measurements. Seebeck coefficient was found to be positive over entire temperature range, indicating that (In{sub 0.5}Sb{sub 0.5}){sub 1-x}Te{sub x} films are p-type semiconducting materials. Also, the variation of the mobility with temperature has been estimated. Increasing tellurium concentration is found to affect the DC conductivity and thermoelectric power of the studied films. The activation energies obtained from the DC conductivity and thermoelectric power increase with increasing tellurium content. The obtained results were interpreted according to the chemical bond approach. (orig.)

  9. Thermoelectricity Generation and Electron-Magnon Scattering in a Natural Chalcopyrite Mineral from a Deep-Sea Hydrothermal Vent.

    Science.gov (United States)

    Ang, Ran; Khan, Atta Ullah; Tsujii, Naohito; Takai, Ken; Nakamura, Ryuhei; Mori, Takao

    2015-10-26

    Current high-performance thermoelectric materials require elaborate doping and synthesis procedures, particularly in regard to the artificial structure, and the underlying thermoelectric mechanisms are still poorly understood. Here, we report that a natural chalcopyrite mineral, Cu1+x Fe1-x S2 , obtained from a deep-sea hydrothermal vent can directly generate thermoelectricity. The resistivity displayed an excellent semiconducting character, and a large thermoelectric power and high power factor were found in the low x region. Notably, electron-magnon scattering and a large effective mass was detected in this region, thus suggesting that the strong coupling of doped carriers and antiferromagnetic spins resulted in the natural enhancement of thermoelectric properties during mineralization reactions. The present findings demonstrate the feasibility of thermoelectric energy generation and electron/hole carrier modulation with natural materials that are abundant in the Earth's crust. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Measurement of the thermoelectric properties of quasicrystalline AlPdRe and AlCuFe alloys

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, M L; LeGault, S; Stroud, R M; Tritt, T M

    1997-07-01

    The authors report the measurement of the thermal conductivity, electrical resistivity, and thermoelectric power on two quasicrystalline compounds, Al{sub 70}Pd{sub 20}Re{sub 10} and Al{sub 62.5}Cu{sub 25}Fe{sub 12.5}. These materials are found to possess a thermal conductivity of order 1 W/m{center{underscore}dot}K, while retaining their semimetallic conductivity. These features coupled with moderately large thermopowers, up to 55 {micro}V/K, imply that the general class of quasicrystalline compounds warrants careful investigation for their potential as new thermoelectric materials.

  11. Glances on the year 1998. Energies and raw materials; Regards sur 1998. Energies et matieres premieres

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-11-01

    This report summarizes 14 key-topics of the year 1998 in relation with the French energy and economic policy: the new start-up of energy mastery; the nuclear industry between passion and reason; the labour inspection in nuclear power plants; the law project for the modernizing and development of the electric power public utility; the main gas transportation systems; the future of Gardanne`s mining basin; the raw materials in the upheaval; the French refining activity after the Auto-Oil directive; the oil company fusions; the priorities in petroleum technology research; the policy of automotive fuels distribution; the energy in regions; the mining activity in New Caledonia; the end of the BRGM-Normandy partnership. A calendar of remarkable facts is given at the end. (J.S.)

  12. Polymer Materials for the Heat Recovery

    International Nuclear Information System (INIS)

    Kolasińska, E; Mazurek, B; Kolasiński, P

    2016-01-01

    Many of the processes in the industry, agriculture and microscale systems are associated with the waste heat generation, which often may be a menace or lower the efficiency of the processes. The thermoelectric cooling is becoming increasingly popular and gives the possibility to convert waste heat into electricity. The current thermoelectric cooling solutions are based on alloy materials. However, the new technologies pay attention to the environment burden, moreover the regulations of the production and recycling are becoming more and more restrictive. Conducting polymers are thermoelectrically active at low temperatures, cheap and environmentally safe. In this paper authors discuss the possibility of the application of conducting polymers for the heat recovery. Due to the operating temperature range and different nature of the waste heat sources, polymers might be an interesting solution and a complement for alloy-based thermoelectric materials. The character and nature of the formation of waste heat sources and conventional technologies of its recovery are also described in this paper. Moreover the advantages of thermoelectric cooling with the use of polymers are presented and two materials based on polyaniline are proposed. (paper)

  13. Misfit Layer Compounds and Ferecrystals: Model Systems for Thermoelectric Nanocomposites

    Directory of Open Access Journals (Sweden)

    Devin R. Merrill

    2015-04-01

    Full Text Available A basic summary of thermoelectric principles is presented in a historical context, following the evolution of the field from initial discovery to modern day high-zT materials. A specific focus is placed on nanocomposite materials as a means to solve the challenges presented by the contradictory material requirements necessary for efficient thermal energy harvest. Misfit layer compounds are highlighted as an example of a highly ordered anisotropic nanocomposite system. Their layered structure provides the opportunity to use multiple constituents for improved thermoelectric performance, through both enhanced phonon scattering at interfaces and through electronic interactions between the constituents. Recently, a class of metastable, turbostratically-disordered misfit layer compounds has been synthesized using a kinetically controlled approach with low reaction temperatures. The kinetically stabilized structures can be prepared with a variety of constituent ratios and layering schemes, providing an avenue to systematically understand structure-function relationships not possible in the thermodynamic compounds. We summarize the work that has been done to date on these materials. The observed turbostratic disorder has been shown to result in extremely low cross plane thermal conductivity and in plane thermal conductivities that are also very small, suggesting the structural motif could be attractive as thermoelectric materials if the power factor could be improved. The first 10 compounds in the [(PbSe1+δ]m(TiSe2n family (m, n ≤ 3 are reported as a case study. As n increases, the magnitude of the Seebeck coefficient is significantly increased without a simultaneous decrease in the in-plane electrical conductivity, resulting in an improved thermoelectric power factor.

  14. New Technology for Microfabrication and Testing of a Thermoelectric Device for Generating Mobile Electrical Power

    Science.gov (United States)

    Prasad, Narasimha S.; Taylor, Patrick J.; Trivedi, Sudhir B.; Kutcher, Susan

    2012-01-01

    Thermoelectric (TE) power generation is an increasingly important power generation technology. Major advantages include: no moving parts, low-weight, modularity, covertness/silence, high power density, low amortized cost, and long service life with minimum or no required maintenance. Despite low efficiency of power generation, there are many specialized needs for electrical power that TE technologies can uniquely and successfully address. Recent advances in thermoelectric materials technology have rekindled acute interest in thermoelectric power generation. We have developed single crystalline n- and p- type PbTe crystals and are also, developing PbTe bulk nanocomposites using PbTe nano powders and emerging filed assisted sintering technology (FAST). We will discuss the materials requirements for efficient thermoelectric power generation using waste heat at intermediate temperature range (6500 to 8500 K). We will present our recent results on production of n- and p- type PbTe crystals and their thermoelectric characterization. Relative characteristics and performance of PbTe bulk single crystals and nano composites for thermoelectric power generation will be discussed.

  15. Design and Optimization of Effective Segmented Thermoelectric Generator for Waste Heat Recovery

    DEFF Research Database (Denmark)

    Pham, Hoang Ngan

    ranges of 300 ‒ 700, and 900 – 1100 K are considered. The obtained results reveals that segmented thermoelectric generator comprising of Bi0.6Sb1.4Te3/Ba8Au5.3Ge40.7/PbTe-SrTe/SiGe as p-leg and either segmented Bi2Te3/PbTe/SiGe or Bi2Te3/Ba0.08La0.05Yb0.04Co4Sb12/La3Te4 as n-leg working in 300 – 1100 K...... been focused on material development, realizing high efficient thermoelectric generators from such well-developed materials is still limited. Moreover, no single thermoelectric material could withstand the wide temperature range required to boost efficiency of TEGs. By segmentation of different TE...... materials which operate optimally in each temperature range, this study aims at developing high performance segmented TEGs for medium-high (450 – 850 K) temperature application. The research is focused on the challenges in joining and minimizing the contact resistances between different TE materials...

  16. New Insight on Tuning Electrical Transport Properties via Chalcogen Doping in n-type Mg3Sb2-Based Thermoelectric Materials

    DEFF Research Database (Denmark)

    Zhang, Jiawei; Song, Lirong; Borup, Kasper

    2018-01-01

    n-type Mg3Sb1.5Bi0.5 has recently been discovered to be a promising thermoelectric material, yet the effective n-type dopants are mainly limited to the chalcogens. This may be attributed to the limited chemical insight into the effects from different n-type dopants. By comparing the effects of di...

  17. Thermoelectric properties control due to doping level and sintering conditions for FGM thermoelectric element

    CERN Document Server

    Kajikawa, T; Shiraishi, K; Ohmori, M; Hirai, T

    1999-01-01

    Thermoelectric performance is determined with three factors, namely, Seebeck coefficient, electrical resistivity and thermal conductivity. For metal and single crystalline semiconductor, those factors have close interrelation each $9 other. However, as the sintered thermoelectric element has various levels of superstructure from macro scale and micro scale in terms of the thermoelectric mechanism, the relationship among them is more complex than that for the $9 melt- grown element, so it is suggested that the control of the temperature dependence of thermoelectric properties is possible to enhance the thermoelectric performance for wide temperature range due to FGM approach. The research $9 objective is to investigate the characteristics of the thermoelectric properties for various doping levels and hot-pressed conditions to make the thermoelectric elements for which the temperature dependence of the performance is $9 controlled due to FGM approach varying the doping levels and sintering conditions. By usage ...

  18. Analysis of a sandwich-type generator with self-heating thermoelectric elements

    International Nuclear Information System (INIS)

    Kim, Mikyung; Yang, Hyein; Wee, Daehyun

    2014-01-01

    Highlights: • A novel and unique type of thermoelectric generators is proposed. • Heat source is combined in thermoelectric elements, reducing heat transfer problems. • Embedding radioactive isotopes is proposed as a way to implement the new design. • Conversion efficiency and power density are estimated for the proposed design. - Abstract: A novel and unique design of thermoelectric generators, in which a heat source is combined with thermoelectric elements, is proposed. By placing heat-generating radioactive isotopes inside the thermoelectric elements, the heat transfer limitation between the generator and the heat source can be eliminated, ensuring simplicity. The inner electrode is sandwiched between identical thermoelectric elements, which naturally allows the inner core to act as the hot side. Analysis shows that conversion efficiency and power density increase as the heat density inside the thermoelectric elements increases and as the thermoelectric performance of the material improves. The theoretical maximum efficiency is shown to be 50%. However, realistic performance under practical constraint is much worse. In realistic cases, the efficiency would be about 3% at best. The power density of the proposed design exhibits a much more reasonable value as high as 3000 W/m 2 . Although the efficiency is low, the simplicity of the proposed design combined with its reasonable power density may result in some, albeit limited, potential applications. Further investigation must be performed in order to realize such potential

  19. Flexible and self-powered temperature-pressure dual-parameter sensors using microstructure-frame-supported organic thermoelectric materials

    Science.gov (United States)

    Zhang, Fengjiao; Zang, Yaping; Huang, Dazhen; di, Chong-An; Zhu, Daoben

    2015-09-01

    Skin-like temperature- and pressure-sensing capabilities are essential features for the next generation of artificial intelligent products. Previous studies of e-skin and smart elements have focused on flexible pressure sensors, whereas the simultaneous and sensitive detection of temperature and pressure with a single device remains a challenge. Here we report developing flexible dual-parameter temperature-pressure sensors based on microstructure-frame-supported organic thermoelectric (MFSOTE) materials. The effective transduction of temperature and pressure stimuli into two independent electrical signals permits the instantaneous sensing of temperature and pressure with an accurate temperature resolution of cost and large-area fabrication, make MFSOTE materials possess promising applications in e-skin and health-monitoring elements.

  20. Convergence of valence bands for high thermoelectric performance for p-type InN

    International Nuclear Information System (INIS)

    Li, Hai-Zhu; Li, Ruo-Ping; Liu, Jun-Hui; Huang, Ming-Ju

    2015-01-01

    Band engineering to converge the bands to achieve high valley degeneracy is one of effective approaches for designing ideal thermoelectric materials. Convergence of many valleys in the valence band may lead to a high Seebeck coefficient, and induce promising thermoelectric performance of p-type InN. In the current work, we have systematically investigated the electronic structure and thermoelectric performance of wurtzite InN by using the density functional theory combined with semiclassical Boltzmann transport theory. Form the results, it can be found that intrinsic InN has a large Seebeck coefficient (254 μV/K) and the largest value of Z e T is 0.77. The transport properties of p-type InN are better than that of n-type one at the optimum carrier concentration, which mainly due to the large Seebeck coefficient for p-type InN, although the electrical conductivity of n-type InN is larger than that of p-type one. We found that the larger Seebeck coefficient for p-type InN may originate from the large valley degeneracy in the valence band. Moreover, the low minimum lattice thermal conductivity for InN is one key factor to become a good thermoelectric material. Therefore, p-type InN could be a potential material for further applications in the thermoelectric area.

  1. BiCuSeO Thermoelectrics: An Update on Recent Progress and Perspective

    Directory of Open Access Journals (Sweden)

    Xiaoxuan Zhang

    2017-02-01

    Full Text Available A BiCuSeO system has been reported as a promising thermoelectric material and has attracted great attention in the thermoelectric community since 2010. Recently, several remarkable studies have been reported and the ZT of BiCuSeO was pushed to a higher level. It motivates us to systematically summarize the recent reports on the BiCuSeO system. In this short review, we start with several attempts to optimize thermoelectric properties of BiCuSeO. Then, we introduce several opinions to explore the origins of low thermal conductivity for BiCuSeO. Several approaches to enhance thermoelectric performance are also summarized, including modulation doping, introducing dual-vacancies, and dual-doping, etc. At last, we propose some possible strategies for enhancing thermoelectric performance of BiCuSeO in future research.

  2. Design Optimization of a Thermoelectric Cooling Module Using Finite Element Simulations

    Science.gov (United States)

    Abid, Muhammad; Somdalen, Ragnar; Rodrigo, Marina Sancho

    2018-05-01

    The thermoelectric industry is concerned about the size reduction, cooling performance and, ultimately, the production cost of thermoelectric modules. Optimization of the size and performance of a commercially available thermoelectric cooling module is considered using finite element simulations. Numerical simulations are performed on eight different three-dimensional geometries of a single thermocouple, and the results are further extended for a whole module as well. The maximum temperature rise at the hot and cold sides of a thermocouple is determined by altering its height and cross-sectional area. The influence of the soldering layer is analyzed numerically using temperature dependent and temperature independent thermoelectric properties of the solder material and the semiconductor pellets. Experiments are conducted to test the cooling performance of the thermoelectric module and the results are compared with the results obtained through simulations. Finally, cooling rate and maximum coefficient of performance (COPmax) are computed using convective and non-convective boundary conditions.

  3. Impact of microstructure on the thermoelectric properties of the ternary compound Ce{sub 3}Cu{sub 3}Sb{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Witas, Piotr, E-mail: pwitas@us.edu.pl [Institute of Physics, University of Silesia, Uniwersytecka 4, Katowice 40-007 (Poland); Goraus, Jerzy; Zajdel, Paweł; Balin, Katarzyna; Koperski, Janusz [Institute of Physics, University of Silesia, Uniwersytecka 4, Katowice 40-007 (Poland); Lelątko, Józef [Institute of Materials Science, University of Silesia, 75 Pułku Piechoty 1a, Chorzów 41-500 (Poland); Ślebarski, Andrzej [Institute of Physics, University of Silesia, Uniwersytecka 4, Katowice 40-007 (Poland)

    2017-01-15

    We present detailed structural and thermoelectric studies of the ternary compound Ce{sub 3}Cu{sub 3}Sb{sub 4}. This material is of interest due to previously reported considerable thermopower above room temperature (∼ 100 μV/K) and low thermal conductivity (2 W/(m K)). Here, we present detailed studies concerning microstructural and thermoelectric data, their variation across the samples and possible explanations for the observed behaviour. We have used X-ray diffraction, scanning electron microscopy (SEM), and time-of-flight secondary ion mass spectrometry (TOF-SIMS) for microstructural analysis. The thermoelectric properties were examined using a physical property measurement system (PPMS). We analyse the impact of the sample quality on the thermoelectric properties. The most unstable parameter is the material resistivity which varies between 1.5 and 15 mΩ cm at room temperature. The properties variability is mainly due to structural defects caused by stresses during material preparation and also due to formation of foreign phases CeCuSb{sub 2} and CeSb. The figure of merit ZT is also strongly dependent on the quality of the sample. The largest value ZT ≈ 0.15 at 400 K is determined for the almost stoichiometric sample with small amounts of a impurity phases. - Highlights: •The Ce{sub 3}Cu{sub 3}Sb{sub 4} has considerable thermoelectric properties and potential for further chemical and/or structural modification. •The control over foreign phases formation is challenging. •The defects arising during arc melting process highly deteriorate ZT of material.

  4. Thermoelectricity an introduction to the principles

    CERN Document Server

    MacDonald, D K C

    2006-01-01

    This introductory treatment provides an understanding of the fundamental concepts and principles involved in the study of thermoelectricity in solids and of conduction in general. Aimed at graduate-level students and those interested in basic theory, it will be especially valuable to experimental physicists working in fields connected with electron transport and to theoreticians seeking a survey of thermoelectricity and related questions.Chronicling the early history of thermoelectricity from its discovery to modern times, this text features a considerable amount of experimental data and discu

  5. Thermoelectric performance enhancement of SrTiO3 by Pr doping

    KAUST Repository

    Kahaly, M. Upadhyay; Schwingenschlö gl, Udo

    2014-01-01

    We investigate Pr doping at the Sr site as a possible route to enhance the thermoelectric behavior of SrTiO3-based materials, using first principles calculations in full-potential density functional theory. The effects of the Pr dopant on the local electronic structure and resulting transport properties are compared to common Nb doping. We demonstrate a substantial enhancement of the thermoelectric figure of merit and develop an explanation for the positive effects, which opens new ways for materials optimization by substitutional doping at the perovskite B site. © 2014 the Partner Organisations.

  6. Importance of non-parabolic band effects in the thermoelectric properties of semiconductors

    Science.gov (United States)

    Chen, Xin; Parker, David; Singh, David J.

    2013-01-01

    We present an analysis of the thermoelectric properties of of n-type GeTe and SnTe in relation to the lead chalcogenides PbTe and PbSe. We find that the singly degenerate conduction bands of semiconducting GeTe and SnTe are highly non-ellipsoidal, even very close to the band edges. This leads to isoenergy surfaces with a strongly corrugated shape that is clearly evident at carrier concentrations well below 0.005 e per formula unit (7–9 × 1019 cm−3 depending on material). Analysis within Boltzmann theory suggests that this corrugation may be favorable for the thermoelectric transport. Our calculations also indicate that values of the power factor for these two materials may well exceed those of PbTe and PbSe. As a result these materials may exhibit n-type performance exceeding that of the lead chalcogenides. PMID:24196778

  7. About thermo-electric properties of bismuth telluride doped by gadolinium

    International Nuclear Information System (INIS)

    Akperov, M.M.; Ismailov, Sh.S.; Shukyurova, A.A.

    2004-01-01

    Results of study of the Gd impurities effect on the bismuth telluride thermo-electric properties are presented. The experiment was carried out within the temperature range T=300-700 K. It is determined, that at temperature increase the energy level is appreciably closing up to bismuth telluride forbidden zone which makes up 0.16-0.24 eV. Such anomalous energy properties of gadolinium in telluride affect on material thermoelectric properties

  8. Numerical simulations on the temperature gradient and thermal stress of a thermoelectric power generator

    International Nuclear Information System (INIS)

    Wu, Yongjia; Ming, Tingzhen; Li, Xiaohua; Pan, Tao; Peng, Keyuan; Luo, Xiaobing

    2014-01-01

    Highlights: • An appropriate ceramic plate thickness is effective in alleviating the thermal stress. • A smaller distance between thermo-pins can help prolong lifecycle of the TE module. • Either a thicker or a thinner copper conducting strip effectively reduces thermal stress. • A suitable tin soldering thickness will alleviate thermal stress intensity and increase thermal efficiency. - Abstract: Thermoelectric generator is a device taking advantage of the temperature difference in thermoelectric material to generate electric power, where the higher the temperature difference of the hot-cold ends, the higher the efficiency will be. However, higher temperature or higher heat flux upon the hot end will cause strong thermal stress which will negatively influence the lifecycle of the thermoelectric module. This phenomenon is very common in industrial applications but seldom has research work been reported. In this paper, numerical analysis on the thermodynamics and thermal stress performance of the thermoelectric module has been performed, considering the variation on the thickness of materials; the influence of high heat flux on thermal efficiency, power output, and thermal stress has been examined. It is found that under high heat flux imposing upon the hot end, the thermal stress is so strong that it has a decisive effect on the life expectation of the device. To improve the module’s working condition, different geometrical configurations are tested and the optimum sizes are achieved. Besides, the side effects on the efficiency, power output, and open circuit voltage output of the thermoelectric module are taken into consideration

  9. Revealing the optoelectronic and thermoelectric properties of the Zintl quaternary arsenides ACdGeAs{sub 2} (A = K, Rb)

    Energy Technology Data Exchange (ETDEWEB)

    Azam, Sikander; Khan, Saleem Ayaz [New Technologies—Research Center, University of West Bohemia, Univerzitni 8, 306 14 Pilsen (Czech Republic); Goumri-Said, Souraya, E-mail: Souraya.Goumri-Said@chemistry.gatech.edu [School of Chemistry and Biochemistry and Center for Organic Photonics and Electronics, Georgia Institute of Technology, Atlanta, GA 30332-0400 (United States)

    2015-10-15

    Highlights: • Zintl tetragonal phase ACdGeAs{sub 2} (A = K, Rb) are chalcopyrite and semiconductors. • Their direct band gap is suitable for PV, optolectronic and thermoelectric applications. • Combination of DFT and Boltzmann transport theory is employed. • The present arsenides are found to be covalent materials. - Abstract: Chalcopyrite semiconductors have attracted much attention due to their potential implications in photovoltaic and thermoelectric applications. First principle calculations were performed to investigate the electronic, optical and thermoelectric properties of the Zintl tetragonal phase ACdGeAs{sub 2} (A = K, Rb) using the full potential linear augmented plane wave method and the Engle–Vosko GGA (EV–GGA) approximation. The present compounds are found semiconductors with direct band gap and covalent bonding character. The optical transitions are investigated via the dielectric function (real and imaginary parts) along with other related optical constants including refractive index, reflectivity and energy-loss spectrum. Combining results from DFT and Boltzmann transport theory, we reported the thermoelectric properties such as the Seebeck’s coefficient, electrical and thermal conductivity, figure of merit and power factor as function of temperatures. The present chalcopyrite Zintl quaternary arsenides deserve to be explored for their potential applications as thermoelectric materials and for photovoltaic devices.

  10. Rapid characterization of thermoelectric properties of composition spread (La1-xCax)VO3 films

    International Nuclear Information System (INIS)

    Itaka, K.; Wang, Q.J.; Minami, H.; Kawaji, H.; Koinuma, H.

    2004-01-01

    Vanadium oxides possess various interesting properties due to multivalence of a vanadium atom and attract our interest as a target material for the exploration of new applications. We investigated vanadates (La 1-x Ca x )VO 3 with a perovskite structure as thermoelectric (TE) materials because heavy electrons in vanadates are expected to generate large thermopower. To proceed the investigation of thermoelectric properties of the composition spread library more efficiently, we devised a new instrument of multi-channel measurement of their thermoelectric properties. The polarity of Seebeck coefficients changed from positive (0≤x≤0.2) to negative (0.2 3 (x∼0)

  11. Preparation and optimization of thermoelectric properties of Bi2Te3 based alloys using the waste particles as raw materials from the cutting process of the zone melting crystal rods

    Science.gov (United States)

    Xiang, Qiusheng; Fan, Xi'an; Han, Xuewu; Zhang, Chengcheng; Hu, Jie; Feng, Bo; Jiang, Chengpeng; Li, Guangqiang; Li, Yawei; He, Zhu

    2017-12-01

    The p-type Bi2Te3 alloys were prepared using the waste particles from the cutting process of the zone melting crystal rods as the main raw materials by impurity removal process including washing, carbon monoxide reduction and vacuum metallurgical process. The thermoelectric properties of the Bi2Te3 based bulk materials were optimized by component adjustment, second smelting and resistance pressing sintering (RPS) process. All evidences confirmed that most of impurities from the line cutting process and the oxidation such as Sb2O3, Bi2O3 and Bi2Te4O11 could be removed by carbon monoxide reduction and vacuum metallurgical process adopted in this work, and the recycling yield was higher than 97%. Appropriate component adjustment treatment was used to optimize the carrier content and corresponding thermoelectric properties. Lastly, a Bi0.36Sb1.64Te3 bulk was obtained and its power factor (PF) could reach 4.24 mW m-1 K-2 at 300 K and the average PF value was over 3.2 mW m-1 K-2 from 300 K to 470 K, which was equivalent with the thermoelectric performance of the zone melting products from high purity elements Bi, Te and Sb. It was worth mentioning that the recovery process introduced here was a simple, low-cost, high recovery rate and green recycling technology.

  12. Thermoelectric transport properties of high mobility organic semiconductors

    Science.gov (United States)

    Venkateshvaran, Deepak; Broch, Katharina; Warwick, Chris N.; Sirringhaus, Henning

    2016-09-01

    Transport in organic semiconductors has traditionally been investigated using measurements of the temperature and gate voltage dependent mobility of charge carriers within the channel of organic field-effect transistors (OFETs). In such measurements, the behavior of charge carrier mobility with temperature and gate voltage, studied together with carrier activation energies, provide a metric to quantify the extent of disorder within these van der Waals bonded materials. In addition to the mobility and activation energy, another potent but often-overlooked transport coefficient useful in understanding disorder is the Seebeck coefficient (also known as thermoelectric power). Fundamentally, the Seebeck coefficient represents the entropy per charge carrier in the solid state, and thus proves powerful in distinguishing materials in which charge carriers move freely from those where a high degree of disorder causes the induced carriers to remain trapped. This paper briefly covers the recent highlights in the field of organic thermoelectrics, showing how significant strides have been made both from an applied standpoint as well as from a viewpoint of fundamental thermoelectric transport physics. It shall be illustrated how thermoelectric transport parameters in organic semiconductors can be tuned over a significant range, and how this tunability facilitates an enhanced performance for heat-to-electricity conversion as well as quantifies energetic disorder and the nature of the density of states (DOS). The work of the authors shall be spotlighted in this context, illustrating how Seebeck coefficient measurements in the polymer indacenodithiophene-co-benzothiadiazole (IDTBT) known for its ultra-low degree of torsion within the polymer backbone, has a trend consistent with low disorder. 1 Finally, using examples of the small molecules C8-BTBT and C10-DNTT, it shall be discussed how the Seebeck coefficient can aid the estimation of the density and distribution of trap states

  13. Reduction of the thermal conductivity of the thermoelectric material ScN by Nb alloying

    DEFF Research Database (Denmark)

    Tureson, Nina; Van Nong, Ngo; Fournier, Daniele

    2017-01-01

    ) orientation. The crystal structure, morphology, thermal conductivity, and thermoelectric and electrical properties were investigated. The ScN reference film exhibited a Seebeck coefficient of −45 μV/K and a power factor of 6 × 10−4 W/m K2 at 750 K. Estimated from room temperature Hall measurements, all...... samples exhibit a high carrier density of the order of 1021 cm−3. Inclusion of heavy transition metals into ScN enables the reduction in thermal conductivity by an increase in phonon scattering. The Nb inserted ScN thin films exhibited a thermal conductivity lower than the value of the ScN reference (10.......5 W m−1 K−1) down to a minimum value of 2.2 Wm−1 K−1. Insertion of Nb into ScN thus resulted in a reduction in thermal conductivity by a factor of ∼5 due to the mass contrast in ScN, which increases the phonon scattering in the material....

  14. Synthesis, Processing, and Thermoelectric Properties of Germanium-Antimony-Tellurium Based Compounds and Alloys

    Science.gov (United States)

    Williams, Jared Brett

    Society has become increasingly more aware of the negative impacts which nonrenewable energy sources have on the environment, and therefore the search for new and more efficient means of energy production has become an important research endeavor. Thermoelectric modules possess the unique ability to convert wasted heat into useful electrical energy via solid state processes, which could vastly improve the efficiency of a number of applications. The materials which accomplish this are typically comprised of semiconductors which exhibit high electrical conductivity, Seebeck coefficient, and thermal resistivity. Together these properties give us a gauge for the overall efficiency of the thermal to electrical energy conversion. Phase change materials are a class of materials primarily used for optical data storage in CDs, DVDs, and Blu-Ray discs. Today's state of the art phase change materials are based on alloys of GeTe and Sb2Te3. These materials have also been found to exhibit high thermoelectric efficiencies. These high efficiencies stem from their complex crystal structure and degenerate semiconducting nature. The purpose of this work was to study and engineer the thermoelectric properties of various alloys and compounds which belong to this family of materials. Specifically studied were the compounds Ge4SbTe5 and Ge17Sb2Te20. In each case various synthesis and processing strategies were implemented to increase the thermoelectric performance and better understand the fundamental electrical and thermal properties. Finally various proposals for future work on these materials are presented, all of which are based on the findings described herein.

  15. Fiscal 2000 achievement report on the venture business assisting type regional consortium - Core industry creation type. Thermoelectric energy recovery system for automobile; 2000 nendo chiiki consortium kenkyu kaihatsu jigyo seika hokokusho. Jidoshayo netsuden energy kaishu system

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-03-01

    The project aims to develop a system for recovering heat from the thermal energy of automobile exhaust in the form of electric energy. Skutterudite based thermoelectric materials for high temperature use and existing thermoelectric materials for low/middle temperature use were improved in performance, and a dimensionless thermoelectric performance index of ZT=1 was attained. Advanced processes were applied for improvement on the performance of existing thermoelectric materials. In the effort to develop technologies for the mass production of thermoelectric materials for high temperature use, a material manufacturing process was established for manufacturing materials excellent in thermoelectric and mechanical properties using a method for mass-producing sinterable materials by gas atomization and a large discharge plasma sintering process capable of treating large specimens. In the effort to improve automobile power generation modules in performance and to establish element technologies for their manufacture, technologies were developed involving thermoelectric materials and electrodes, bonding of different thermoelectric materials, bonding of heat conducting electrical insulators and electrodes, and high efficiency segment type power generation modules. A high performance automobile exhaust gas heat exchanger was developed. A Co-Sb based thermoelectric module and a Bi-Te based module were combined and the package was tested aboard automobiles, when a maximum power output of 83W was achieved. It is necessary to review module arrangement. (NEDO)

  16. Notes on Computational Methodology and Tools of Thermoelectric Energy Systems

    DEFF Research Database (Denmark)

    Chen, Min; Bach, Inger Palsgaard; Rosendahl, Lasse

    2007-01-01

    The SPICE model allows the concurrent simulation of thermoelectric devices and application electric sub-models. It is an important step to implement the thermoelectric modeling at the system level. In this paper, temperature dependent material properties in the SPICE model, temperature and heat...... flow obtained by the code ANSYS Multiphysics and SPICE (Simulation Program with Integrated Circuit Emphasis), as well as some notes on the 3-D extension of the SPICE model are introduced....

  17. Annual report - ABACC (accounting and nuclear materials control Brazil-Argentina agency) - 1998

    International Nuclear Information System (INIS)

    1999-01-01

    The annual activities report of 1998 of accounting and nuclear materials control Brazil-Argentina agency introduces the next main topics: institutional activities - safeguards agreements implementation and administration; technical activities - planning and evaluation, operation, technical support, information accounting and treatment, technical cooperation, technical capacity invigoration; administrative and financial activities

  18. A Method for testing the integrated thermal resistance of thermoelectric modules

    Science.gov (United States)

    Gao, Junling; Du, Qungui; Chen, Min

    2013-11-01

    The integrated thermal resistance (ITR) of thermoelectric modules (TEMs) is an important parameter that represents the thermal-conduction of ceramic substrates, copper conducting strips, and welding material used in the TEM as well as the thermal contact resistances between different materials. In this study, an accurate and practical test method is proposed for the ITR of TEMs according to thermoelectric heat transfer theory and the equivalent characteristics of heat flux through the cold and hot sides of TEMs in an open-circuit situation. By using such measurements and comparisons, it is verified that the measured ITR value in our mode is accurate and reliable. In particular this method accurately predicts the actual operating conditions of TEMs, in which TEMs are under certain mechanical pressure. It effectively solves the problem of thermal resistance extraction from operating TEMs and is of great significance in their analysis and optimization.

  19. Characteristics and parametric analysis of a novel flexible ink-based thermoelectric generator for human body sensor

    DEFF Research Database (Denmark)

    Qing, Shaowei; Rezaniakolaei, Alireza; Rosendahl, Lasse Aistrup

    2018-01-01

    Flexible thermoelectric generator became an attractive technology for its wide use especially for curved surfaces applications. This study proposes design of a flexible thermoelectric generator, which is part of a sensor and supplies required electrical power for human body application...... elements thickness and thermoelectric module row number in a proper range can significantly enhance thermoelectric generator performance. The maximum output power can reach 0.2 μW/cm2, which indicates the proposed design is promising for supplying human body sensors. In addition, the basic optimal design....... The thermoelectric generator module has ink-based thermoelements which are made of nano-carbon bismuth telluride materials. Flexible fins conduct the body heat to the thermoelectric uni-couples, extended fins exchange the heat from the cold side of the thermoelectric generator to the ambient. A fully developed one...

  20. Hall and thermoelectric evaluation of p-type InAs

    Energy Technology Data Exchange (ETDEWEB)

    Wagener, M.C., E-mail: magnus.wagener@nmmu.ac.z [Department of Physics, Nelson Mandela Metropolitan University, Port Elizabeth (South Africa); Wagener, V.; Botha, J.R. [Department of Physics, Nelson Mandela Metropolitan University, Port Elizabeth (South Africa)

    2009-12-15

    This paper compares the galvanometric and thermoelectric evaluation of the electrical characteristics of narrow gap semiconductors. In particular, the influence of a surface inversion layer is incorporated into the analysis of the temperature-dependent Hall and thermoelectric measurements of p-type InAs. The temperature at which the Seebeck coefficient of p-type material changes sign is shown to be unaffected by the presence of degenerate conduction paths. This finding consequently facilitated the direct determination of the acceptor density of lightly doped thin film InAs.

  1. Hall and thermoelectric evaluation of p-type InAs

    International Nuclear Information System (INIS)

    Wagener, M.C.; Wagener, V.; Botha, J.R.

    2009-01-01

    This paper compares the galvanometric and thermoelectric evaluation of the electrical characteristics of narrow gap semiconductors. In particular, the influence of a surface inversion layer is incorporated into the analysis of the temperature-dependent Hall and thermoelectric measurements of p-type InAs. The temperature at which the Seebeck coefficient of p-type material changes sign is shown to be unaffected by the presence of degenerate conduction paths. This finding consequently facilitated the direct determination of the acceptor density of lightly doped thin film InAs.

  2. The effect of Cr buffer layer thickness on voltage generation of thin-film thermoelectric modules

    International Nuclear Information System (INIS)

    Mizoshiri, Mizue; Mikami, Masashi; Ozaki, Kimihiro

    2013-01-01

    The effect of Cr buffer layer thickness on the open-circuit voltage generated by thin-film thermoelectric modules of Bi 0.5 Sb 1.5 Te 3 (p-type) and Bi 2 Te 2.7 Se 0.3 (n-type) materials was investigated. A Cr buffer layer, whose thickness generally needs to be optimized to improve adhesion depending on the substrate surface condition, such as roughness, was deposited between thermoelectric thin films and glass substrates. When the Cr buffer layer was 1 nm thick, the Seebeck coefficients and electrical conductivity of 1 µm thermoelectric thin films with the buffer layers were approximately equal to those of the thermoelectric films without the buffer layers. When the thickness of the Cr buffer layer was 1 µm, the same as the thermoelectric films, the Seebeck coefficients of the bilayer films were reduced by an electrical current flowing inside the Cr buffer layer and the generation of Cr 2 Te 3 . The open-circuit voltage of the thin-film thermoelectric modules decreased with an increase in the thickness of the Cr buffer layer, which was primarily induced by the electrical current flow. The reduction caused by the Cr 2 Te 3 generation was less than 10% of the total voltage generation of the modules without the Cr buffer layers. The voltage generation of thin-film thermoelectric modules could be controlled by the Cr buffer layer thickness. (paper)

  3. Modeling and Experimentation of New Thermoelectric Cooler–Thermoelectric Generator Module

    Directory of Open Access Journals (Sweden)

    Khaled Teffah

    2018-03-01

    Full Text Available In this work, a modeling and experimental study of a new thermoelectric cooler–thermoelectric generator (TEC-TEG module is investigated. The studied module is composed of TEC, TEG and total system heatsink, all connected thermally in series. An input voltage (1–5 V passes through the TEC where the electrons by means of Peltier effect entrain the heat from the upper side of the module to the lower one creating temperature difference; TEG plays the role of a partial heatsink for the TEC by transferring this waste heat to the total system heatsink and converting an amount of this heat into electricity by a phenomenon called Seebeck effect, of the thermoelectric modules. The performance of the TEG as partial heatsink of TEC at different input voltages is demonstrated theoretically using the modeling software COMSOL Multiphysics. Moreover, the experiment validates the simulation result which smooths the path for a new manufacturing thermoelectric cascade model for the cooling and the immediate electric power generation.

  4. High thermoelectric performance of graphite nanofibers

    OpenAIRE

    Tran, Van-Truong; Saint-Martin, Jérôme; Dollfus, Philippe; Volz, Sebastian

    2017-01-01

    Graphite nanofibers (GNFs) have been demonstrated to be a promising material for hydrogen storage and heat management in electronic devices. Here, by means of first-principles and transport simulations, we show that GNFs can also be an excellent material for thermoelectric applications thanks to the interlayer weak van der Waals interaction that induces low thermal conductance and a step-like shape in the electronic transmission with mini-gaps, which are necessary ingredients to achieve high ...

  5. Characterization of the interface between an Fe–Cr alloy and the p-type thermoelectric oxide Ca3Co4O9

    DEFF Research Database (Denmark)

    Holgate, Tim; Han, Li; Wu, NingYu

    2014-01-01

    A customized Fe–Cr alloy that has been optimized for high temperature applications in oxidizing atmospheres has been interfaced via spark plasma sintering (SPS) with a p-type thermoelectric oxide material: calcium cobaltate (Ca3Co4O9). The properties of the alloy have been analyzed for its...... calcium and chromium in the interface that is highly resistive at room temperature, but conducting at the intended thermoelectric device hot-side operating temperature of 800 °C. As the alloy is well matched in terms of its thermal expansion and highly conducting compared to the Ca3Co4O9, it may...... be further considered as an interconnect material candidate at least with application on the hot-side of an oxide thermoelectric power generation module....

  6. Thermal conductivity engineering in width-modulated silicon nanowires and thermoelectric efficiency enhancement

    Science.gov (United States)

    Zianni, Xanthippi

    2018-03-01

    Width-modulated nanowires have been proposed as efficient thermoelectric materials. Here, the electron and phonon transport properties and the thermoelectric efficiency are discussed for dimensions above the quantum confinement regime. The thermal conductivity decreases dramatically in the presence of thin constrictions due to their ballistic thermal resistance. It shows a scaling behavior upon the width-modulation rate that allows for thermal conductivity engineering. The electron conductivity also decreases due to enhanced boundary scattering by the constrictions. The effect of boundary scattering is weaker for electrons than for phonons and the overall thermoelectric efficiency is enhanced. A ZT enhancement by a factor of 20-30 is predicted for width-modulated nanowires compared to bulk silicon. Our findings indicate that width-modulated nanostructures are promising for developing silicon nanostructures with high thermoelectric efficiency.

  7. Parametric optimization of thermoelectric elements footprint for maximum power generation

    DEFF Research Database (Denmark)

    Rezania, A.; Rosendahl, Lasse; Yin, Hao

    2014-01-01

    The development studies in thermoelectric generator (TEG) systems are mostly disconnected to parametric optimization of the module components. In this study, optimum footprint ratio of n- and p-type thermoelectric (TE) elements is explored to achieve maximum power generation, maximum cost......-performance, and variation of efficiency in the uni-couple over a wide range of the heat transfer coefficient on the cold junction. The three-dimensional (3D) governing equations of the thermoelectricity and the heat transfer are solved using the finite element method (FEM) for temperature dependent properties of TE...... materials. The results, which are in good agreement with the previous computational studies, show that the maximum power generation and the maximum cost-performance in the module occur at An/Ap

  8. Maximization of the Thermoelectric Cooling of a Graded Peltier Device by Analytical Heat-Equation Resolution

    Science.gov (United States)

    Thiébaut, E.; Goupil, C.; Pesty, F.; D'Angelo, Y.; Guegan, G.; Lecoeur, P.

    2017-12-01

    Increasing the maximum cooling effect of a Peltier cooler can be achieved through material and device design. The use of inhomogeneous, functionally graded materials may be adopted in order to increase maximum cooling without improvement of the Z T (figure of merit); however, these systems are usually based on the assumption that the local optimization of the Z T is the suitable criterion to increase thermoelectric performance. We solve the heat equation in a graded material and perform both analytical and numerical analysis of a graded Peltier cooler. We find a local criterion that we use to assess the possible improvement of graded materials for thermoelectric cooling. A fair improvement of the cooling effect (up to 36%) is predicted for semiconductor materials, and the best graded system for cooling is described. The influence of the equation of state of the electronic gas of the material is discussed, and the difference in term of entropy production between the graded and the classical system is also described.

  9. Thermal Stress Analysis and Structure Parameter Selection for a Bi2Te3-Based Thermoelectric Module

    Science.gov (United States)

    Gao, Jun-Ling; Du, Qun-Gui; Zhang, Xiao-Dan; Jiang, Xin-Qiang

    2011-05-01

    The output power and conversion efficiency of thermoelectric modules (TEMs) are mainly determined by their material properties, i.e., Seebeck coefficient, electrical resistivity, and thermal conductivity. In practical applications, due to the influence of the harsh environment, the mechanical properties of TEMs should also be considered. Using the finite-element analysis (FEA) model in ANSYS software, we present the thermal stress distribution of a TEM based on the anisotropic mechanical properties and thermoelectric properties of hot-pressed materials. By analyzing the possibilities of damage along the cleavage plane of Bi2Te3-based thermoelectric materials and by optimizing the structure parameters, a TEM with better mechanical performance is obtained. Thus, a direction for improving the thermal stress resistance of TEMs is presented.

  10. Influence of germanium nano-inclusions on the thermoelectric power factor of bulk bismuth telluride alloy

    International Nuclear Information System (INIS)

    Satyala, Nikhil; Zamanipour, Zahra; Norouzzadeh, Payam; Krasinski, Jerzy S.; Vashaee, Daryoosh; Tahmasbi Rad, Armin; Tayebi, Lobat

    2014-01-01

    Nanocomposite thermoelectric compound of bismuth telluride (Bi 2 Te 3 ) with 5 at. % germanium nano-inclusions was prepared via mechanically alloying and sintering techniques. The influence of Ge nano-inclusions and long duration annealing on the thermoelectric properties of nanostructured Bi 2 Te 3 were investigated. It was found that annealing has significant effect on the carrier concentration, Seebeck coefficient, and the power factor of the thermoelectric compound. The systematic heat treatment also reduced the density of donor type defects thereby decreasing the electron concentration. While the as-pressed nanocomposite materials showed n-type properties, it was observed that with the increase of annealing time, the nanocomposite gradually transformed to an abundantly hole-dominated (p-type) sample. The long duration annealing (∼500 h) resulted in a significantly enhanced electrical conductivity pertaining to the augmentation in the density and the structural properties of the sample. Therefore, a simultaneous enhancement in both electrical and Seebeck coefficient characteristics resulted in a remarkable increase in the thermoelectric power factor.

  11. New thinking on modeling of thermoelectric devices

    International Nuclear Information System (INIS)

    Zhang, T.

    2016-01-01

    Highlights: • New model was developed for performance calculation of thermoelectric devices. • The model takes into account the temperature-dependent material properties. • It takes into account the spatial-dependent heat flow rate in thermoelement. • It can take into account the heat and electricity losses at the junctions. • It can probe a broad range of parameters for module performance optimization. - Abstract: The performance of a thermoelectric power generation (TEPG) module and a device designed to convert engine exhaust heat directly into electricity was studied under different operating conditions using a proposed thermoelectric (TE) model in this work. The proposed model was obtained from the first law of thermodynamics, Ohm’s law, nonlinear analytical solution of thermoelectric transport equation, and a control volume that represents a typical TEPG module or device such that the temperature-dependent material properties of, the spatial-dependent heat flow rate through the TE element, and the interfacial electrical and thermal losses can be taken into account in the performance calculation. The performance of a typical TEPG module under a broad range of cold-side temperatures and the temperature differences between its hot-side and cold-side was calculated by the proposed model and the results agree very well with the existing model predictions. Comparison between the model predictions and the experimental results confirmed that reducing the interfacial electric resistance can enhance the module performance. The inter-dependence of the key thermal and TEPG system design and optimization parameters was examined for a real TEPG device using the proposed model and an optimal module fill factor of 0.35 was found within the given mass flow rates between 0.0154 and 0.052 kg/s of exhaust stream.

  12. Optimization Strategies for a Portable Thermoelectric Vaccine Refrigeration System in Developing Communities

    Science.gov (United States)

    Ohara, B.; Sitar, R.; Soares, J.; Novisoff, P.; Nunez-Perez, A.; Lee, H.

    2015-06-01

    The traditional approach to determine an optimum current for thermoelectric cooling assumes that a refrigeration chamber is insulated and has no thermal resistance to a thermoelectric module. As a result, minimum temperature occurs when Peltier cooling matches with parasitic heat transfer and Joule heating. In practical application, minimum temperature happens when heat addition from the environment is matched with heat extracted by a thermoelectric module, and the optimum current differs from that anticipated by the traditional approach. Hence, consideration for insulation and thermal resistances via thermoelectric module should be made to achieve desirable cooling performance/refrigeration temperature. This paper presents a modeling approach to determine the optimum current as well as the optimum geometry to power a small thermoelectric vaccine delivery system for developing communities under the World Health Organization requirements. The model is derived from three energy conservation equations for temperatures at both ends of the thermoelectric materials within a module, as well as the refrigeration chamber temperature. A prototype was built and demonstrated a minimum temperature of 3.4°C. With optimized module geometry, the system is estimated to reduce power consumption by over 50% while achieving twice the temperature difference.

  13. Maximum Efficiency of Thermoelectric Heat Conversion in High-Temperature Power Devices

    Directory of Open Access Journals (Sweden)

    V. I. Khvesyuk

    2016-01-01

    Full Text Available Modern trends in development of aircraft engineering go with development of vehicles of the fifth generation. The features of aircrafts of the fifth generation are motivation to use new high-performance systems of onboard power supply. The operating temperature of the outer walls of engines is of 800–1000 K. This corresponds to radiation heat flux of 10 kW/m2 . The thermal energy including radiation of the engine wall may potentially be converted into electricity. The main objective of this paper is to analyze if it is possible to use a high efficiency thermoelectric conversion of heat into electricity. The paper considers issues such as working processes, choice of materials, and optimization of thermoelectric conversion. It presents the analysis results of operating conditions of thermoelectric generator (TEG used in advanced hightemperature power devices. A high-temperature heat source is a favorable factor for the thermoelectric conversion of heat. It is shown that for existing thermoelectric materials a theoretical conversion efficiency can reach the level of 15–20% at temperatures up to 1500 K and available values of Ioffe parameter being ZT = 2–3 (Z is figure of merit, T is temperature. To ensure temperature regime and high efficiency thermoelectric conversion simultaneously it is necessary to have a certain match between TEG power, temperature of hot and cold surfaces, and heat transfer coefficient of the cooling system. The paper discusses a concept of radiation absorber on the TEG hot surface. The analysis has demonstrated a number of potentialities for highly efficient conversion through using the TEG in high-temperature power devices. This work has been implemented under support of the Ministry of Education and Science of the Russian Federation; project No. 1145 (the programme “Organization of Research Engineering Activities”.

  14. Optimization of Thermoelectric Components for Automobile Waste Heat Recovery Systems

    Science.gov (United States)

    Kumar, Sumeet; Heister, Stephen D.; Xu, Xianfan; Salvador, James R.

    2015-10-01

    For a typical spark ignition engine approximately 40% of available thermal energy is lost as hot exhaust gas. To improve fuel economy, researchers are currently evaluating technology which exploits exhaust stream thermal power by use of thermoelectric generators (TEGs) that operate on the basis of the Seebeck effect. A 5% improvement in fuel economy, achieved by use of TEG output power, is a stated objective for light-duty trucks and personal automobiles. System modeling of thermoelectric (TE) components requires solution of coupled thermal and electric fluxes through the n and p-type semiconductor legs, given appropriate thermal boundary conditions at the junctions. Such applications have large thermal gradients along the semiconductor legs, and material properties are highly dependent on spatially varying temperature profiles. In this work, one-dimensional heat flux and temperature variations across thermoelectric legs were solved by using an iterative numerical approach to optimize both TE module and TEG designs. Design traits were investigated by assuming use of skutterudite as a thermoelectric material with potential for automotive applications in which exhaust gas and heat exchanger temperatures typically vary from 100°C to over 600°C. Dependence of leg efficiency, thermal fluxes and electric power generation on leg geometry, fill fractions, electric current, thermal boundary conditions, etc., were studied in detail. Optimum leg geometries were computed for a variety of automotive exhaust conditions.

  15. Heat shrink formation of a corrugated thin film thermoelectric generator

    International Nuclear Information System (INIS)

    Sun, Tianlei; Peavey, Jennifer L.; David Shelby, M.; Ferguson, Scott; O’Connor, Brendan T.

    2015-01-01

    Highlights: • Demonstrate and characterize a thermoelectric generator with a corrugated geometry. • Employ a novel heat shrink fabrication approach compatible with low-cost processing. • Use thermal impedance modeling to explore design potential. • Corrugated design shown to be advantageous for low heat-flux density applications. - Abstract: A thin film thermoelectric (TE) generator with a corrugated architecture is demonstrated formed using a heat-shrink fabrication approach. Fabrication of the corrugated TE structure consists of depositing thin film thermoelectric elements onto a planar non-shrink polyimide substrate that is then sandwiched between two uniaxial stretch-oriented co-polyester (PET) films. The heat shrink PET films are adhered to the polyimide in select locations, such that when the structure is placed in a high temperature environment, the outer films shrink resulting in a corrugated core film and thermoelectric elements spanning between the outer PET films. The module has a cross-plane heat transfer architecture similar to a conventional bulk TE module, but with heat transfer in the plane of the thin film thermoelectric elements, which assists in maintaining a significant temperature difference across the thermoelectric junctions. In this demonstration, Ag and Ni films are used as the thermoelectric elements and a Seebeck coefficient of 14 μV K −1 is measured with a maximum power output of 0.22 nW per couple at a temperature difference of 7.0 K. We then theoretically consider the performance of this device architecture with high performance thermoelectric materials in the heat sink limited regime. The results show that the heat-shrink approach is a simple fabrication method that may be advantageous in large-area, low power density applications. The fabrication method is also compatible with simple geometric modification to achieve various form factors and power densities to customize the TE generator for a range of applications

  16. Thermoelectric micro converters for cooling and energy-scavenging systems

    International Nuclear Information System (INIS)

    Goncalves, L M; Couto, C; Correia, J H; Alpuim, P

    2008-01-01

    This paper describes the fabrication process of thermoelectric microconverters, based on n-type bismuth telluride (Bi 2 Te 3 ) and p-type antimony telluride (Sb 2 Te 3 ) thin films. The films are fabricated by thermal co-evaporation with thermoelectric properties comparable to those reported for the same materials in bulk form (used in conventional macro-scale Peltier modules). The absolute value of the Seebeck coefficient in the range of 150–250 µV K −1 and an in-plane electrical resistivity of 7–15 µΩ m were obtained. The influence of fabrication parameters on thermoelectric properties is reported. The films were patterned by photolithography and wet-etching techniques, using HNO 3 /HCl-based etchants. The influence of composition and concentration of etchants in the lithographic process is reported. A microcooler was fabricated

  17. Lunar base thermoelectric power station study

    Science.gov (United States)

    Determan, William; Frye, Patrick; Mondt, Jack; Fleurial, Jean-Pierre; Johnson, Ken; Stapfer, G.; Brooks, Michael D.; Heshmatpour, Ben

    2006-01-01

    Under NASA's Project Prometheus, the Nuclear Systems Program, the Jet Propulsion Laboratory, Pratt & Whitney Rocketdyne, and Teledyne Energy Systems have teamed with a number of universities, under the Segmented Thermoelectric Multicouple Converter (STMC) program, to develop the next generation of advanced thermoelectric converters for space reactor power systems. Work on the STMC converter assembly has progressed to the point where the lower temperature stage of the segmented multicouple converter assembly is ready for laboratory testing and the upper stage materials have been identified and their properties are being characterized. One aspect of the program involves mission application studies to help define the potential benefits from the use of these STMC technologies for designated NASA missions such as the lunar base power station where kilowatts of power are required to maintain a permanent manned presence on the surface of the moon. A modular 50 kWe thermoelectric power station concept was developed to address a specific set of requirements developed for this mission. Previous lunar lander concepts had proposed the use of lunar regolith as in-situ radiation shielding material for a reactor power station with a one kilometer exclusion zone radius to minimize astronaut radiation dose rate levels. In the present concept, we will examine the benefits and requirements for a hermetically-sealed reactor thermoelectric power station module suspended within a man-made lunar surface cavity. The concept appears to maximize the shielding capabilities of the lunar regolith while minimizing its handling requirements. Both thermal and nuclear radiation levels from operation of the station, at its 100-m exclusion zone radius, were evaluated and found to be acceptable. Site preparation activities are reviewed and well as transport issues for this concept. The goal of the study was to review the entire life cycle of the unit to assess its technical problems and technology

  18. Performance of a Composite Thermoelectric Generator with Different Arrangements of SiGe, BiTe and PbTe under Different Configurations

    Directory of Open Access Journals (Sweden)

    Alexander Vargas-Almeida

    2015-10-01

    Full Text Available In this study, we analyze the role of the thermoelectric (TE properties, namely Seebeck coefficient α, thermal conductivity κ and electrical resistivity ρ, of three different materials in a composite thermoelectric generator (CTEG under different configurations. The CTEG is composed of three thermoelectric modules (TEMs: (1 two TEMs thermally and electrically connected in series (SC; (2 two branches of TEMs thermally and electrically connected in parallel (PSC; and (3 three TEMs thermally and electrically connected in parallel (TEP. In general, each of the TEMs have different thermoelectric parameters, namely a Seebeck coefficient α, a thermal conductance K and an electrical resistance R. Following the framework proposed recently, we show the effect of: (1 the configuration; and (2 the arrangements of TE materials on the corresponding equivalent figure of merit Zeq and consequently on the maximum power Pmax and efficiency η of the CTEG. Firstly, we consider that the whole system is formed of the same thermoelectric material (α1,K1,R1 = α2,K2,R2 = α3,K3,R3 and, secondly, that the whole system is constituted by only two different thermoelectric materials Entropy 2015, 17 7388 (αi,Ki,Ri ≠ αj ,Kj ,Rj 6= αl,Kl,Rl, where i, j, l can be 1, 2 or 3. In this work, we propose arrangements of TEMs, which clearly have the advantage of a higher thermoelectric figure of merit value compared to a conventional thermoelectric module. A corollary about the Zeq-max for CTEG is obtained as a result of these considerations. We suggest an optimum configuration.

  19. A design approach for integrating thermoelectric devices using topology optimization

    International Nuclear Information System (INIS)

    Soprani, S.; Haertel, J.H.K.; Lazarov, B.S.; Sigmund, O.; Engelbrecht, K.

    2016-01-01

    Highlights: • The integration of a thermoelectric (TE) cooler into a robotic tool is optimized. • Topology optimization is suggested as design tool for TE integrated systems. • A 3D optimization technique using temperature dependent TE properties is presented. • The sensitivity of the optimization process to the boundary conditions is studied. • A working prototype is constructed and compared to the model results. - Abstract: Efficient operation of thermoelectric devices strongly relies on the thermal integration into the energy conversion system in which they operate. Effective thermal integration reduces the temperature differences between the thermoelectric module and its thermal reservoirs, allowing the system to operate more efficiently. This work proposes and experimentally demonstrates a topology optimization approach as a design tool for efficient integration of thermoelectric modules into systems with specific design constraints. The approach allows thermal layout optimization of thermoelectric systems for different operating conditions and objective functions, such as temperature span, efficiency, and power recovery rate. As a specific application, the integration of a thermoelectric cooler into the electronics section of a downhole oil well intervention tool is investigated, with the objective of minimizing the temperature of the cooled electronics. Several challenges are addressed: ensuring effective heat transfer from the load, minimizing the thermal resistances within the integrated system, maximizing the thermal protection of the cooled zone, and enhancing the conduction of the rejected heat to the oil well. The design method incorporates temperature dependent properties of the thermoelectric device and other materials. The 3D topology optimization model developed in this work was used to design a thermoelectric system, complete with insulation and heat sink, that was produced and tested. Good agreement between experimental results and

  20. Universal Majorana thermoelectric noise

    Science.gov (United States)

    Smirnov, Sergey

    2018-04-01

    Thermoelectric phenomena resulting from an interplay between particle flows induced by electric fields and temperature inhomogeneities are extremely insightful as a tool providing substantial knowledge about the microscopic structure of a given system. By tuning, e.g., parameters of a nanoscopic system coupled via tunneling mechanisms to two contacts, one may achieve various situations where the electric current induced by an external bias voltage competes with the electric current excited by the temperature difference of the two contacts. Even more exciting physics emerges when the system's electronic degrees freedom split to form Majorana fermions which make the thermoelectric dynamics universal. Here, we propose revealing these unique universal signatures of Majorana fermions in strongly nonequilibrium quantum dots via noise of the thermoelectric transport beyond linear response. It is demonstrated that whereas mean thermoelectric quantities are only universal at large-bias voltages, the noise of the electric current excited by an external bias voltage and the temperature difference of the contacts is universal at any bias voltage. We provide truly universal, i.e., independent of the system's parameters, thermoelectric ratios between nonlinear response coefficients of the noise and mean current at large-bias voltages where experiments may easily be performed to uniquely detect these truly universal Majorana thermoelectric signatures.

  1. P-type Al-doped Cr-deficient CrN thin films for thermoelectrics

    DEFF Research Database (Denmark)

    Febvrier, Arnaud le; Van Nong, Ngo; Abadias, Gregory

    2018-01-01

    Thermoelectric properties of chromium nitride (CrN)-based films grown on c-plane sapphire by dc reactive magnetron sputtering were investigated. In this work, aluminum doping was introduced in CrN (degenerate n-type semiconductor) by co-deposition. Under the present deposition conditions, over......-type/n-type thermoelectric materials based on chromium nitride films, which are cheap and routinely grown on the industrial scale....

  2. A study on heat transfer enhancement using flow channel inserts for thermoelectric power generation

    International Nuclear Information System (INIS)

    Lesage, Frédéric J.; Sempels, Éric V.; Lalande-Bertrand, Nathaniel

    2013-01-01

    Highlights: • Thermal enhancement in a thermoelectric liquid generator is tested. • Thermal enhancement is brought upon by flow impeding inserts. • CFD simulations attribute thermal enhancement to velocity field alterations. • Thermoelectric power enhancement is measured and discussed. • Power enhancement relative to adverse pressure drop is investigated. - Abstract: Thermoelectric power production has many potential applications that range from microelectronics heat management to large scale industrial waste-heat recovery. A low thermoelectric conversion efficiency of the current state of the art prevents wide spread use of thermoelectric modules. The difficulties lie in material conversion efficiency, module design, and thermal system management. The present study investigates thermoelectric power improvement due to heat transfer enhancement at the channel walls of a liquid-to-liquid thermoelectric generator brought upon by flow turbulating inserts. Care is taken to measure the adverse pressure drop due to the presence of flow impeding obstacles in order to measure the net thermoelectric power enhancement relative to an absence of inserts. The results illustrate the power enhancement performance of three different geometric forms fitted into the channels of a thermoelectric generator. Spiral inserts are shown to offer a minimal improvement in thermoelectric power production whereas inserts with protruding panels are shown to be the most effective. Measurements of the thermal enhancement factor which represents the ratio of heat flux into heat flux out of a channel and numerical simulations of the internal flow velocity field attribute the thermal enhancement resulting in the thermoelectric power improvement to thermal and velocity field synergy

  3. Thermoelectric Properties of Solution-Processed n-Doped Ladder-Type Conducting Polymers

    DEFF Research Database (Denmark)

    Wang, Suhao; Sun, Hengda; Ail, Ujwala

    2016-01-01

    Ladder-type "torsion-free" conducting polymers (e.g., polybenzimidazobenzophenanthroline (BBL)) can outperform "structurally distorted" donor-acceptor polymers (e.g., P(NDI2OD-T2)), in terms of conductivity and thermoelectric power factor. The polaron delocalization length is larger in BBL than...... in P(NDI2OD-T2), resulting in a higher measured polaron mobility. Structure-function relationships are drawn, setting material-design guidelines for the next generation of conducting thermoelectric polymers....

  4. High Power Density, Lightweight Thermoelectric Metamaterials for Energy Harvesting

    Data.gov (United States)

    National Aeronautics and Space Administration — Thermoelectric energy harvesting utilizes materials that generate an electrical current when subjected to a temperature gradient, or simply, a hot and cold source of...

  5. Improvement In The COP Of Thermoelectric Cooler

    Directory of Open Access Journals (Sweden)

    Jatin Patel

    2015-08-01

    Full Text Available This paper described the study for heat transfer through thermoelectric cooler TEC by use of multistage thermoelectric module. To satisfy the heat dissipation of modern electronic element thermal designers have to increase fin area and fan speed to improve its cooling capacity. However the increase of fin area is restricted by the space. Besides the increase of fan speed would induce noise which damages human health. So air cooling by fan is hardly to meet the requirement of modern electronic component. Recently thermoelectric cooler TEC is applied to electronic cooling with the advantages of small size quietness and reliability. A typical thermoelectric cooler consists of p-type and n-type semiconductor pellets connected electrically in series and sandwiched between two ceramic substrates. Whenever direct current passes through the circuit it causes temperature differential between TEC sides. As a result one face of TEC which is called cold side will be cooled while its opposite face which is called hot side is simultaneously heated. The main problem over the use of TEC is the limited COP and its thermal performance. But these can be eliminated by use of multistage thermoelectric cooler.

  6. Method of manufacturing a layer thermoelectric battery. Herstellungsverfahren fuer Schichtthermobatterien

    Energy Technology Data Exchange (ETDEWEB)

    Lidorenko, N.S.; Kolomoets, N.V.; Daschevsky, Z.M.; Granovsky, V.I.; Schemtschuschina, E.A.; Chernousov, L.N.; Schmidt, I.A.; Nikolaschina, L.A.; Gelfgat, D.M.; Sgibnev, I.V.

    1980-08-21

    A method of manufacturing a layer thermoelectric battery is described, whereby a film of a thermoelectric semiconductor material which is an n-type stoichiometric solid solution containing Bi2Te3 and Sb2Te3 is deposited on a substrate. Then heating is effected so that adjacent arms of the film are at different temperatures, some at a temperature of not above 300/sup 0/C, and others at a temperature of not less than 350/sup 0/C.

  7. Very High Output Thermoelectric Devices Based on ITO Nanocomposites

    Science.gov (United States)

    Fralick, Gustave; Gregory, Otto J.

    2009-01-01

    A material having useful thermoelectric properties was synthesized by combining indium-tin-oxide (ITO) with a NiCoCrAlY alloy/alumina cermet. This material had a very large Seebeck coefficient with electromotive-force-versustemperature behavior that is considered to be excellent with respect to utility in thermocouples and other thermoelectric devices. When deposited in thin-film form, ceramic thermocouples offer advantages over precious-metal (based, variously, on platinum or rhodium) thermocouples that are typically used in gas turbines. Ceramic thermocouples exhibit high melting temperatures, chemical stability at high temperatures, and little or no electromigration. Oxide ceramics also resist oxidation better than metal thermocouples, cost substantially less than precious-metal thermocouples, and, unlike precious-metal thermocouples, do not exert catalytic effects.

  8. Fabrication of a Micro Cooler using Thermoelectric Thin Film

    International Nuclear Information System (INIS)

    Han, S. W.; Choi, H. J.; Kim, D. H.; Kim, W. J.; Kim, B. I.; Kim, K. M.

    2007-01-01

    In general a ThermoElectric Cooler (TEC) consists of a series of P type and N type thermoelectric materials sandwiched between two wafers. When a DC current passes through these materials, three different effects take place; Peltier effect, Joule heating effect and heat transfer by conduction due to temperature difference between hot and cold plates. In this study we have developed a micro TEC using Bi2Te3 (N type) and Bi0.5Sb1.5Te3 (P type) thin films. In order to improve that performance of a micro TEC, we made 10 um height TE legs using special PR only for lift-off. We measured COP (coefficient of performance) and temperature difference between hot and cold connectors with current

  9. Manipulation of charge transport in thermoelectrics

    Science.gov (United States)

    Zhang, Xinyue; Pei, Yanzhong

    2017-12-01

    While numerous improvements have been achieved in thermoelectric materials by reducing the lattice thermal conductivity (κL), electronic approaches for enhancement can be as effective, or even more. A key challenge is decoupling Seebeck coefficient (S) from electrical conductivity (σ). The first order approximation - a single parabolic band assumption with acoustic scattering - leads the thermoelectric power factor (S2σ) to be maximized at a constant reduced Fermi level (η 0.67) and therefore at a given S of 167 μV/K. This simplifies the challenge of maximization of σ at a constant η, leading to a large number of degenerate transport channels (band degeneracy, Nv) and a fast transportation of charges (carrier mobility, μ). In this paper, existing efforts on this issue are summarized and future prospectives are given.

  10. Weight Penalty Incurred in Thermoelectric Recovery of Automobile Exhaust Heat

    Science.gov (United States)

    Rowe, D. M.; Smith, J.; Thomas, G.; Min, G.

    2011-05-01

    Thermoelectric recovery of automobile waste exhaust heat has been identified as having potential for reducing fuel consumption and environmentally unfriendly emissions. Around 35% of combustion energy is discharged as heat through the exhaust system, at temperatures which depend upon the engine's operation and range from 800°C to 900°C at the outlet port to less than 50°C at the tail-pipe. Beneficial reduction in fuel consumption of 5% to 10% is widely quoted in the literature. However, comparison between claims is difficult due to nonuniformity of driving conditions. In this paper the available waste exhaust heat energy produced by a 1.5 L family car when undergoing the new European drive cycle was measured and the potential thermoelectric output estimated. The work required to power the vehicle through the drive cycle was also determined and used to evaluate key parameters. This enabled an estimate to be made of the engine efficiency and additional work required by the engine to meet the load of a thermoelectric generating system. It is concluded that incorporating a thermoelectric generator would attract a penalty of around 12 W/kg. Employing thermoelectric modules fabricated from low-density material such as magnesium silicide would considerably reduce the generator weight penalty.

  11. Simple experiments with a thermoelectric module

    International Nuclear Information System (INIS)

    Kraftmakher, Yaakov

    2005-01-01

    The Seebeck and Peltier effects are explored with a commercially available thermoelectric module and a data-acquisition system. Five topics are presented: (i) thermoelectric heating and cooling, (ii) the Seebeck coefficient, (iii) efficiency of a thermoelectric generator, (iv) the maximum temperature difference provided by a thermoelectric cooler and (v) the Peltier coefficient and the coefficient of performance. Using a data-acquisition system, the measurements are carried out in a reasonably short time. It is shown how to deduce quantities important for the theory and applications of thermoelectric devices

  12. Oxidant-Dependent Thermoelectric Properties of Undoped ZnO Films by Atomic Layer Deposition

    KAUST Repository

    Kim, Hyunho

    2017-02-27

    Extraordinary oxidant-dependent changes in the thermoelectric properties of undoped ZnO thin films deposited by atomic layer deposition (ALD) have been observed. Specifically, deionized water and ozone oxidants are used in the growth of ZnO by ALD using diethylzinc as a zinc precursor. No substitutional atoms have been added to the ZnO films. By using ozone as an oxidant instead of water, a thermoelectric power factor (σS) of 5.76 × 10 W m K is obtained at 705 K for undoped ZnO films. In contrast, the maximum power factor for the water-based ZnO film is only 2.89 × 10 W m K at 746 K. Materials analysis results indicate that the oxygen vacancy levels in the water- and ozone-grown ZnO films are essentially the same, but the difference comes from Zn-related defects present in the ZnO films. The data suggest that the strong oxidant effect on thermoelectric performance can be explained by a mechanism involving point defect-induced differences in carrier concentration between these two oxides and a self-compensation effect in water-based ZnO due to the competitive formations of both oxygen and zinc vacancies. This strong oxidant effect on the thermoelectric properties of undoped ZnO films provides a pathway to improve the thermoelectric performance of this important material.

  13. Thermoelectric properties of non-stoichiometric lanthanum sulfides

    International Nuclear Information System (INIS)

    Shapiro, E.; Danielson, L.R.

    1983-01-01

    The lanthanum sulfides are promising candidate materials for high-efficiency thermoelectric applications at temperatures up to 1300 0 C. The nonstoichiometric lanthanum sulfides (LaS /SUB x/ , where 1.33 2 //rho/ can be chosen. The thermal conductivity remains approximately constant with stoichiometry, so a material with an optimum value of α 2 //rho/ should possess the optimum figure-of-merit. Data for the Seebeck coefficient and electrical resistivity of non-stoichiometric lanthanum sulfides is presented, together with structural properties of these materials

  14. System to Measure Thermal Conductivity and Seebeck Coefficient for Thermoelectrics

    Science.gov (United States)

    Kim, Hyun-Jung; Skuza, Jonathan R.; Park, Yeonjoon; King, Glen C.; Choi, Sang H.; Nagavalli, Anita

    2012-01-01

    The Seebeck coefficient, when combined with thermal and electrical conductivity, is an essential property measurement for evaluating the potential performance of novel thermoelectric materials. However, there is some question as to which measurement technique(s) provides the most accurate determination of the Seebeck coefficient at elevated temperatures. This has led to the implementation of nonstandardized practices that have further complicated the confirmation of reported high ZT materials. The major objective of the procedure described is for the simultaneous measurement of the Seebeck coefficient and thermal diffusivity within a given temperature range. These thermoelectric measurements must be precise, accurate, and reproducible to ensure meaningful interlaboratory comparison of data. The custom-built thermal characterization system described in this NASA-TM is specifically designed to measure the inplane thermal diffusivity, and the Seebeck coefficient for materials in the ranging from 73 K through 373 K.

  15. Design of segmented thermoelectric generator based on cost-effective and light-weight thermoelectric alloys

    International Nuclear Information System (INIS)

    Kim, Hee Seok; Kikuchi, Keiko; Itoh, Takashi; Iida, Tsutomu; Taya, Minoru

    2014-01-01

    Highlights: • Segmented thermoelectric (TE) module operating at 500 °C for combustion engine system. • Si based light-weight TE generator increases the specific power density [W/kg]. • Study of contact resistance at the bonding interfaces maximizing output power. • Accurate agreement of the theoretical predictions with experimental results. - Abstract: A segmented thermoelectric (TE) generator was designed with higher temperature segments composed of n-type Mg 2 Si and p-type higher manganese silicide (HMS) and lower temperature segments composed of n- and p-type Bi–Te based compounds. Since magnesium and silicon based TE alloys have low densities, they produce a TE module with a high specific power density that is suitable for airborne applications. A two-pair segmented π-shaped TE generator was assembled with low contact resistance materials across bonding interfaces. The peak specific power density of this generator was measured at 42.9 W/kg under a 498 °C temperature difference, which has a good agreement with analytical predictions

  16. Thermoelectric generator cooling system and method of control

    Science.gov (United States)

    Prior, Gregory P; Meisner, Gregory P; Glassford, Daniel B

    2012-10-16

    An apparatus is provided that includes a thermoelectric generator and an exhaust gas system operatively connected to the thermoelectric generator to heat a portion of the thermoelectric generator with exhaust gas flow through the thermoelectric generator. A coolant system is operatively connected to the thermoelectric generator to cool another portion of the thermoelectric generator with coolant flow through the thermoelectric generator. At least one valve is controllable to cause the coolant flow through the thermoelectric generator in a direction that opposes a direction of the exhaust gas flow under a first set of operating conditions and to cause the coolant flow through the thermoelectric generator in the direction of exhaust gas flow under a second set of operating conditions.

  17. Thermoelectric refrigerator having improved temperature stabilization means

    International Nuclear Information System (INIS)

    Falco, C.M.

    1982-01-01

    A control system for thermoelectric refrigerators is disclosed. The thermoelectric refrigerator includes at least one thermoelectric element that undergoes a first order change at a predetermined critical temperature. The element functions as a thermoelectric refrigerator element above the critical temperature, but discontinuously ceases to function as a thermoelectric refrigerator element below the critical temperature. One example of such an arrangement includes thermoelectric refrigerator elements which are superconductors. The transition temperature of one of the superconductor elements is selected as the temperature control point of the refrigerator. When the refrigerator attempts to cool below the point, the metals become superconductors losing their ability to perform as a thermoelectric refrigerator. An extremely accurate, first-order control is realized

  18. Efficient p-n junction-based thermoelectric generator that can operate at extreme temperature conditions

    DEFF Research Database (Denmark)

    Chavez, Ruben; Angst, Sebastian; Hall, Joseph

    2017-01-01

    In many industrial processes a large proportion of energy is lost in the form of heat. Thermoelectric generators can convert this waste heat into electricity by means of the Seebeck effect. However, the use of thermoelectric generators in practical applications on an industrial scale is limited...... in part because electrical, thermal, and mechanical bonding contacts between the semiconductor materials and the metal electrodes in current designs are not capable of withstanding thermal-mechanical stress and alloying of the metal-semiconductor interface when exposed to the high temperatures occurring...... in many real-world applications. Here we demonstrate a concept for thermoelectric generators that can address this issue by replacing the metallization and electrode bonding on the hot side of the device by a p-n junction between the two semiconductor materials, making the device robust against...

  19. Development of Inexpensive, Efficient and Non-Toxic Thermoelectric Materials

    Science.gov (United States)

    Gali, Anand Pratik

    In the wake of the impending climate change challenges, it is highly necessary to reevaluate our energy utilization technologies and ensure their efficient operation. Fossil fuel powered power-plants account for the majority of the energy production in the United States. With an average efficiency not exceeding 40%, these fossil fuel power plants dissipate exorbitant amounts of wasted heat. One of the ways of making such energy conversion processes more efficient is by incorporating technologies that can harvest this scavenge heat. One of the ways of achieving this is by the use of thermoelectric (TE) materials, which utilize the Seebeck effect to convert thermal gradient into potential difference. Therefore, our research project focusses on development of TE materials, which are inexpensive, efficient, and non-toxic. Fe0.50V0.25Al0.25 is a narrow band-gap semiconductor, ideal for TE applications. Unlike the current market leader Bi0.4Te0.6, Fe0.50V0.25 Al0.25 contains earth abundant and non-toxic constituents making it viable for commercial production. Nevertheless, the TE efficiency, ZT, of Fe0.50V0.25Al0.25 is limited by its high thermal conductivity. Therefore, the goal of the current research is two-fold. Firstly, to design and fabricate apparatus for performing TE characterization on bulk materials. For this purpose, two sets of apparatus were designed and fabricated for measuring high temperature Seebeck coefficient and electrical resistivity. Secondly, to study the influence of doping on TE properties of Fe0.50V0.25Al0.25 alloy. In order to achieve this, vanadium in Fe0.50V0.25Al0.25 was substituted with dopants like Ti, Cr, Zr, W, Nb, Ta. This led to a 20 times improvement in ZT, from the baseline Fe0.50V0.25Al0.25, by effectively reducing the thermal conductivity and increasing the Seebeck coefficient.

  20. High Thermoelectric Power Factor of High-Mobility 2D Electron Gas.

    Science.gov (United States)

    Ohta, Hiromichi; Kim, Sung Wng; Kaneki, Shota; Yamamoto, Atsushi; Hashizume, Tamotsu

    2018-01-01

    Thermoelectric conversion is an energy harvesting technology that directly converts waste heat from various sources into electricity by the Seebeck effect of thermoelectric materials with a large thermopower ( S ), high electrical conductivity (σ), and low thermal conductivity (κ). State-of-the-art nanostructuring techniques that significantly reduce κ have realized high-performance thermoelectric materials with a figure of merit ( ZT = S 2 ∙σ∙ T ∙κ -1 ) between 1.5 and 2. Although the power factor (PF = S 2 ∙σ) must also be enhanced to further improve ZT , the maximum PF remains near 1.5-4 mW m -1 K -2 due to the well-known trade-off relationship between S and σ. At a maximized PF, σ is much lower than the ideal value since impurity doping suppresses the carrier mobility. A metal-oxide-semiconductor high electron mobility transistor (MOS-HEMT) structure on an AlGaN/GaN heterostructure is prepared. Applying a gate electric field to the MOS-HEMT simultaneously modulates S and σ of the high-mobility electron gas from -490 µV K -1 and ≈10 -1 S cm -1 to -90 µV K -1 and ≈10 4 S cm -1 , while maintaining a high carrier mobility (≈1500 cm 2 V -1 s -1 ). The maximized PF of the high-mobility electron gas is ≈9 mW m -1 K -2 , which is a two- to sixfold increase compared to state-of-the-art practical thermoelectric materials.

  1. Quantum Effects in the Thermoelectric Power Factor of Low-Dimensional Semiconductors.

    Science.gov (United States)

    Hung, Nguyen T; Hasdeo, Eddwi H; Nugraha, Ahmad R T; Dresselhaus, Mildred S; Saito, Riichiro

    2016-07-15

    We theoretically investigate the interplay between the confinement length L and the thermal de Broglie wavelength Λ to optimize the thermoelectric power factor of semiconducting materials. An analytical formula for the power factor is derived based on the one-band model assuming nondegenerate semiconductors to describe quantum effects on the power factor of the low-dimensional semiconductors. The power factor is enhanced for one- and two-dimensional semiconductors when L is smaller than Λ of the semiconductors. In this case, the low-dimensional semiconductors having L smaller than their Λ will give a better thermoelectric performance compared to their bulk counterpart. On the other hand, when L is larger than Λ, bulk semiconductors may give a higher power factor compared to the lower dimensional ones.

  2. Investigation of electronic, magnetic and thermoelectric properties of Zr{sub 2}NiZ (Z = Al,Ga) ferromagnets

    Energy Technology Data Exchange (ETDEWEB)

    Yousuf, Saleem, E-mail: nengroosaleem17@gmail.com; Gupta, Dinesh C., E-mail: sosfizix@gmail.com

    2017-05-01

    Systematic investigation of impact of electronic structure and magnetism, on the thermoelectric properties of new Zr{sub 2}NiZ (Z = Al, Ga) Heusler alloys are determined using density functional theory calculations. Half-metallicity with ferromagnetic character is supported by their 100% spin polarizations at the Fermi level. Magnetic moment of ∼3 μ{sub B} is according to the Slater-Puling rule, enables their practical applications. Electron density plots are used to analyse the nature of bonding and chemical composition. Boltzmann's theory is conveniently employed to investigate the thermoelectric properties of these compounds. The analysis of the thermal transport properties specifies the Seebeck coefficient as 25.6 μV/K and 18.6 μV/K at room temperature for Zr{sub 2}NiAl and Zr{sub 2}NiGa, respectively. The half-metallic nature with efficient thermoelectric coefficients suggests the likelihood of these materials to have application in designing spintronic devices and imminent thermoelectric materials. - Highlights: • The compounds are half-metallic ferromagnets. • 100% spin-polarized compounds for spintronics. • Increasing Seebeck coefficient over a wide temperature range. • Zr{sub 2}NiAl is efficient thermoelectric material than Zr{sub 2}NiGa.

  3. Very heavily electron-doped CrSi2 as a high-performance high-temperature thermoelectric material

    International Nuclear Information System (INIS)

    Parker, David; Singh, David J

    2012-01-01

    We analyze the thermoelectric behavior, using first principles and Boltzmann transport calculations, of very heavily electron-doped CrSi 2 and find that at temperatures of 900-1250 K and electron dopings of 1-4 × 10 21 cm -3 , thermopowers as large in magnitude as 200 μV K -1 may be found. Such high thermopowers at such high carrier concentrations are extremely rare, and suggest that excellent thermoelectric performance may be found in these ranges of temperature and doping. (paper)

  4. High Thermoelectric Performance by Convergence of Bands in IV-VI Semiconductors, Heavily Doped PbTe, and Alloys/Nanocomposites

    Science.gov (United States)

    Snyder, G. Jeffrey (Inventor); Pei, Yanzhong (Inventor)

    2015-01-01

    The present invention teaches an effective mechanism for enhancing thermoelectric performance through additional conductive bands. Using heavily doped p-PbTe materials as an example, a quantitative explanation is disclosed, as to why and how these additional bands affect the figure of merit. A high zT of approaching 2 at high temperatures makes these simple, likely more stable (than nanostructured materials) and Tl-free materials excellent for thermoelectric applications.

  5. Influence of Oxygen Partial Pressure during Processing on the Thermoelectric Properties of Aerosol-Deposited CuFeO₂.

    Science.gov (United States)

    Stöcker, Thomas; Exner, Jörg; Schubert, Michael; Streibl, Maximilian; Moos, Ralf

    2016-03-24

    In the field of thermoelectric energy conversion, oxide materials show promising potential due to their good stability in oxidizing environments. Hence, the influence of oxygen partial pressure during synthesis on the thermoelectric properties of Cu-Delafossites at high temperatures was investigated in this study. For these purposes, CuFeO₂ powders were synthetized using a conventional mixed-oxide technique. X-ray diffraction (XRD) studies were conducted to determine the crystal structures of the delafossites associated with the oxygen content during the synthesis. Out of these powders, films with a thickness of about 25 µm were prepared by the relatively new aerosol-deposition (AD) coating technique. It is based on a room temperature impact consolidation process (RTIC) to deposit dense solid films of ceramic materials on various substrates without using a high-temperature step during the coating process. On these dense CuFeO₂ films deposited on alumina substrates with electrode structures, the Seebeck coefficient and the electrical conductivity were measured as a function of temperature and oxygen partial pressure. We compared the thermoelectric properties of both standard processed and aerosol deposited CuFeO₂ up to 900 °C and investigated the influence of oxygen partial pressure on the electrical conductivity, on the Seebeck coefficient and on the high temperature stability of CuFeO₂. These studies may not only help to improve the thermoelectric material in the high-temperature case, but may also serve as an initial basis to establish a defect chemical model.

  6. Analysis Of Power Characteristics Of Model Thermoelectric Generator TEG Small Modular

    Directory of Open Access Journals (Sweden)

    Kisman H. Mahmud

    2017-04-01

    Full Text Available Thermoelectrically Generator TEG can generate electricity from the temperature difference between hot and cold at the junction thermoelectric module with two different semiconductor materials there will be a flow of current through the junction so as to produce a voltage. This principle uses the Seebeck effect thermoelectric generator as a base. By using these principles this research was conducted to determine the potential of the electric energy of the two peltier modules which would be an alternative source for mobile charger using heat from source of methylated. The focus in this research is the testing of the model TEG Thermoelectric Generator Small Modular to generate power with a variety of different materials of 4 namely Bi2Te3 Bismuth Telluride PbTe-Bite CMO and CMO Cascade-32-62S-32-62S Calcium Mangan oxide to use the cold side heat sink and a fan to simulate heat aluminum plate attached to the hot side of the TEG modules with heat source of methylated. Test results on the TEG Small Modular Model for mobile charger output voltage obtained from 2 pieces Bi2Te3 module Bismuth Telluride Peltier strung together a series of 3.01 Volt with amp916T of 22.7 C which produce power of 0.091 Watt.

  7. Enhanced thermoelectric efficiency via orthogonal electrical and thermal conductances in phosphorene.

    Science.gov (United States)

    Fei, Ruixiang; Faghaninia, Alireza; Soklaski, Ryan; Yan, Jia-An; Lo, Cynthia; Yang, Li

    2014-11-12

    Thermoelectric devices that utilize the Seebeck effect convert heat flow into electrical energy and are highly desirable for the development of portable, solid state, passively powered electronic systems. The conversion efficiencies of such devices are quantified by the dimensionless thermoelectric figure of merit (ZT), which is proportional to the ratio of a device's electrical conductance to its thermal conductance. In this paper, a recently fabricated two-dimensional (2D) semiconductor called phosphorene (monolayer black phosphorus) is assessed for its thermoelectric capabilities. First-principles and model calculations reveal not only that phosphorene possesses a spatially anisotropic electrical conductance, but that its lattice thermal conductance exhibits a pronounced spatial-anisotropy as well. The prominent electrical and thermal conducting directions are orthogonal to one another, enhancing the ratio of these conductances. As a result, ZT may reach the criterion for commercial deployment along the armchair direction of phosphorene at T = 500 K and is close to 1 even at room temperature given moderate doping (∼2 × 10(16) m(-2) or 2 × 10(12) cm(-2)). Ultimately, phosphorene hopefully stands out as an environmentally sound thermoelectric material with unprecedented qualities. Intrinsically, it is a mechanically flexible material that converts heat energy with high efficiency at low temperatures (∼300 K), one whose performance does not require any sophisticated engineering techniques.

  8. Feasibility and parametric evaluation of hybrid concentrated photovoltaic-thermoelectric system

    DEFF Research Database (Denmark)

    Rezaniakolaei, Alireza; Rosendahl, Lasse Aistrup

    2017-01-01

    Concentrated photovoltaic (CPV) system integrated with thermoelectric generators (TEGs) is a novel technology that has potential to offer high efficient system. In this study, a thermally coupled model of concentrated photovoltaic-thermoelctric (CPV/TEG) system is established to investigate...... feasibility of the hybrid system over wide range of solar concentrations and different types of heat sinks. The model takes into account critical design parameters in the CPV and the TEG module. The results of this study show that for thermoelectric materials with ZT ≈ 1, the CPV/TEG system is more efficient...

  9. NREL Research Yields Significant Thermoelectric Performance | News | NREL

    Science.gov (United States)

    Chemical and Materials Science and Technology center, said the introduction of SWCNT into fabrics could from an exemplary SWNCT thin film improved thermoelectric properties. The newest paper revealed that that the same SWCNT thin film achieved identical performance when doped with either positive or

  10. Review on the progress of research on functional materials. Superionic conductors: 1997 - 1998

    International Nuclear Information System (INIS)

    Jahja, A.K.; Effendi, Nurdin; Purnama, Safei; Marsongkohadi

    1999-01-01

    For the period of December 1997 - December 1998, two superionic compounds the non-stoichiometric Cu-base Rubidium Copper Iodide Chloride and the silver-based RbAg 4 I 5 were prepared and characterized. In this report some of the result of this cooperation is presented. Activities concerning conductivity and dielectric properties measurement at BATAN laboratory are outlined. Although the high temperature neutron scattering measurements have not been completed until now, a further cooperation involving the preparation and neutron scattering measurements of materials in thin-film and single crystalline morphology is proposed. (author)

  11. Americium-241 radioisotope thermoelectric generator development for space applications

    International Nuclear Information System (INIS)

    Ambrosi, Richard; Williams, Hugo; Samara-Ratna, Piyal

    2013-01-01

    Space nuclear power systems are under development in the UK in collaboration with European partners as part of a European Space Agency (ESA) programme. Radioisotope thermoelectric generators (RTG) are an important element of this new capability in Europe. RTG systems being developed in Europe are targeting the 10 W electric to 50 W electric power generation range adopting a modular scalable approach to the design. Radiogenic decay heat from radioisotopes can be converted to electrical power by using appropriate semiconductor based thermoelectric materials. The plan for Europe is to develop radioisotope space nuclear power systems based on both thermoelectric and Stirling power conversion systems. Although primarily focused on delivering up to 50 W of electrical power, the European radioisotope thermoelectric system development programme is targeting americium-241 as a fuel source and is maximizing the use of commercially available thermoelectric manufacturing processes in order to accelerate the development of power conversion systems. The use of americium provides an economic solution at high isotopic purity and is product of a separation process from stored plutonium produced during the reprocessing of civil nuclear fuel. A laboratory prototype that uses electrical heating as a substitute for the radioisotope was developed to validate the designs. This prototype has now been tested. This paper outlines the requirements for a European americium-241 fuelled RTG, describes the most recent updates in system design and provides further insight into recent laboratory prototype test campaigns. (author)

  12. Americium-241 radioisotope thermoelectric generator development for space applications

    Energy Technology Data Exchange (ETDEWEB)

    Ambrosi, Richard; Williams, Hugo; Samara-Ratna, Piyal, E-mail: rma8@le.ac.uk [University of Leicester, (United Kingdom); and others

    2013-07-01

    Space nuclear power systems are under development in the UK in collaboration with European partners as part of a European Space Agency (ESA) programme. Radioisotope thermoelectric generators (RTG) are an important element of this new capability in Europe. RTG systems being developed in Europe are targeting the 10 W electric to 50 W electric power generation range adopting a modular scalable approach to the design. Radiogenic decay heat from radioisotopes can be converted to electrical power by using appropriate semiconductor based thermoelectric materials. The plan for Europe is to develop radioisotope space nuclear power systems based on both thermoelectric and Stirling power conversion systems. Although primarily focused on delivering up to 50 W of electrical power, the European radioisotope thermoelectric system development programme is targeting americium-241 as a fuel source and is maximizing the use of commercially available thermoelectric manufacturing processes in order to accelerate the development of power conversion systems. The use of americium provides an economic solution at high isotopic purity and is product of a separation process from stored plutonium produced during the reprocessing of civil nuclear fuel. A laboratory prototype that uses electrical heating as a substitute for the radioisotope was developed to validate the designs. This prototype has now been tested. This paper outlines the requirements for a European americium-241 fuelled RTG, describes the most recent updates in system design and provides further insight into recent laboratory prototype test campaigns. (author)

  13. Phase Change Material Based Accumulation Panels in Combination with Renewable Energy Sources and Thermoelectric Cooling

    Directory of Open Access Journals (Sweden)

    Jan Skovajsa

    2017-01-01

    Full Text Available The article deals with the use of modern materials and technologies that can improve the thermal comfort in buildings. The article describes the design and usage of a special accumulation device, which is composed of thermal panels based on phase change materials (PCMs. The thermal panels have an integrated tube heat exchanger and heating foils. The technology can be used as a passive or active system for heating and cooling. It is designed as a “green technology”, so it is able to use renewable energy sources, e.g., photovoltaic (PV panels, solar thermal collectors and heat pumps. Moreover, an interesting possibility is the ability to use thermoelectric coolers. In the research, measurements of the different operating modes were made, and the results are presented in the text. The measurement approves that the technology improves the thermal capacity of the building, and it is possible to use it for active heating and cooling.

  14. Apparatus, System, and Method for On-Chip Thermoelectricity Generation

    KAUST Repository

    Hussain, Muhammad Mustafa

    2012-01-26

    An apparatus, system, and method for a thermoelectric generator. In some embodiments, the thermoelectric generator comprises a first thermoelectric region and a second thermoelectric region, where the second thermoelectric region may be coupled to the first thermoelectric region by a first conductor. In some embodiments, a second conductor may be coupled to the first thermoelectric region and a third conductor may be coupled to the second thermoelectric region. In some embodiments, the first conductor may be in a first plane, the first thermoelectric region and the second thermoelectric region may be in a second plane, and the second conductor and the third conductor may be in a third plane.

  15. Apparatus, System, and Method for On-Chip Thermoelectricity Generation

    KAUST Repository

    Hussain, Muhammad Mustafa; Fahad, Hossain M.; Rojas, Jhonathan Prieto

    2012-01-01

    An apparatus, system, and method for a thermoelectric generator. In some embodiments, the thermoelectric generator comprises a first thermoelectric region and a second thermoelectric region, where the second thermoelectric region may be coupled to the first thermoelectric region by a first conductor. In some embodiments, a second conductor may be coupled to the first thermoelectric region and a third conductor may be coupled to the second thermoelectric region. In some embodiments, the first conductor may be in a first plane, the first thermoelectric region and the second thermoelectric region may be in a second plane, and the second conductor and the third conductor may be in a third plane.

  16. Flexible thermoelectric generator using bulk legs and liquid metal interconnects for wearable electronics

    International Nuclear Information System (INIS)

    Suarez, Francisco; Parekh, Dishit P.; Ladd, Collin; Vashaee, Daryoosh; Dickey, Michael D.; Öztürk, Mehmet C.

    2017-01-01

    Highlights: •Flexible thermoelectric generator (TEG) with bulk legs. •Flexible thermoelectric generator with liquid metal interconnects. •Flexible TEG with potential to match the performance of rigid TEGs. •Flexible TEG for wearable electronics. -- Abstract: Interest in wearable electronics for continuous, long-term health and performance monitoring is rapidly increasing. The reduction in power levels consumed by sensors and electronic circuits accompanied by the advances in energy harvesting methods allows for the realization of self-powered monitoring systems that do not have to rely on batteries. For wearable electronics, thermoelectric generators (TEGs) offer the unique ability to continuously convert body heat into usable energy. For body harvesting, it is preferable to have TEGs that are thin, soft and flexible. Unfortunately, the performances of flexible modules reported to date have been far behind those of their rigid counterparts. This is largely due to lower efficiencies of the thermoelectric materials, electrical or thermal parasitic losses and limitations on leg dimensions posed by the synthesis techniques. In this work, we present an entirely new approach and explore the possibility of using standard bulk legs in a flexible package. Bulk thermoelectric legs cut from solid ingots are far superior to thermoelectric materials synthesized using other techniques. A key enabler of the proposed technology is the use of EGaIn liquid metal interconnects, which not only provide extremely low interconnect resistance but also stretchability with self-healing, both of which are essential for flexible TE modules. The results suggest that this novel approach can finally produce flexible TEGs that have the potential to challenge the rigid TEGs and provide a pathway for the realization of self-powered wearable electronics.

  17. High-temperature thermoelectric properties of the β-As2−xBixTe3 solid solution

    Directory of Open Access Journals (Sweden)

    J.-B. Vaney

    2016-10-01

    Full Text Available Bi2Te3-based compounds are a well-known class of outstanding thermoelectric materials. β-As2Te3, another member of this family, exhibits promising thermoelectric properties around 400 K when appropriately doped. Herein, we investigate the high-temperature thermoelectric properties of the β-As2−xBixTe3 solid solution. Powder X-ray diffraction and scanning electron microscopy experiments showed that a solid solution only exists up to x = 0.035. We found that substituting Bi for As has a beneficial influence on the thermopower, which, combined with extremely low thermal conductivity values, results in a maximum ZT value of 0.7 at 423 K for x = 0.017 perpendicular to the pressing direction.

  18. Thermoelectric properties of silicon nano pillars

    Energy Technology Data Exchange (ETDEWEB)

    Stranz, Andrej; Soekmen, Uensal; Waag, Andreas; Peiner, Erwin [Institute of Semiconductor Technology, Braunschweig (Germany)

    2010-07-01

    In order to establish silicon as a efficient thermoelectric material, its high thermal conductivity has to be reduced which is feasible, e.g., by nano structuring. Therefore, in this study Si-based sub-micron pillars of various dimensions were investigated. Using anisotropic etching followed by thermal oxidation we could fabricate pillars of diameters <500 nm, about 25 {mu}m in height with aspect ratios of more than 50. The distance between the pillars was varied from 500 nm to 10 micron. Besides the fabrication and structural characterization of sub-micron silicon pillars, and adequate metrology for measuring their thermoelectric properties was implemented. Commercial tungsten probes and self-made gold probes, as well as Wollaston wire probes were used for electrical and thermal conductivity, as well as Seebeck voltage measurements on single pillars in a scanning electron microscope equipped with nano manipulators.

  19. Roles of Cu in the Enhanced Thermoelectric Properties in Bi0.5Sb1.5Te₃.

    Science.gov (United States)

    Hao, Feng; Qiu, Pengfei; Song, Qingfeng; Chen, Hongyi; Lu, Ping; Ren, Dudi; Shi, Xun; Chen, Lidong

    2017-03-01

    Recently, Cu-containing p-type Bi 0.5 Sb 1.5 Te₃ materials have shown high thermoelectric performances and promising prospects for practical application in low-grade waste heat recovery. However, the position of Cu in Bi 0.5 Sb 1.5 Te₃ is controversial, and the roles of Cu in the enhancement of thermoelectric performance are still not clear. In this study, via defects analysis and stability test, the possibility of Cu intercalation in p-type Bi 0.5 Sb 1.5 Te₃ materials has been excluded, and the position of Cu is identified as doping at the Sb sites. Additionally, the effects of Cu dopants on the electrical and thermal transport properties have been systematically investigated. Besides introducing additional holes, Cu dopants can also significantly enhance the carrier mobility by decreasing the Debye screen length and weakening the interaction between carriers and phonons. Meanwhile, the Cu dopants interrupt the periodicity of lattice vibration and bring stronger anharmonicity, leading to extremely low lattice thermal conductivity. Combining the suppression on the intrinsic excitation, a high thermoelectric performance-with a maximum thermoelectric figure of merit of around 1.4 at 430 K-has been achieved in Cu 0.005 Bi 0.5 Sb 1.495 Te₃, which is 70% higher than the Bi 0.5 Sb 1.5 Te₃ matrix.

  20. High temperature thermoelectric energy conversion

    International Nuclear Information System (INIS)

    Wood, C.

    1986-01-01

    Considerable advances were made in the late '50's and early early '60's in the theory and development of materials for high-temperature thermoelectric energy conversion. This early work culminated in a variety of materials, spanning a range of temperatures, with the product of the figure of merit, Z, and temperature, T, i.e., the dimensionless figure of merit, ZT, of the order of one. This experimental limitation appeared to be universal and led a number of investigators to explore the possibility that a ZT - also represents a theoretical limitation. It was found not to be so

  1. Thermoelectric properties of WSi{sub 2}–Si{sub x}Ge{sub 1−x} composites

    Energy Technology Data Exchange (ETDEWEB)

    Dynys, F.W.; Sayir, A. [NASA Glenn Research Center, Cleveland, OH 44135 (United States); Mackey, J., E-mail: jam151@zips.uakron.edu [Department of Mechanical Engineering, University of Akron, Akron, OH 44325 (United States); Sehirlioglu, A. [Department of Materials Science and Engineering, Case Western Reserve University, Cleveland, OH 44106 (United States)

    2014-08-01

    Highlights: • We explore a novel W/Si/Ge composite system for thermoelectric applications. • The influence of crucible selection on electrical properties is investigated. • Introduction of W can reduce the expensive Ge component of the alloy. - Abstract: Thermoelectric properties of the W/Si/Ge alloy system have been investigated with varying concentration levels of germanium and tungsten. The alloys were fabricated by directional solidification with the Bridgman method using boron nitride and fused silica crucibles. The effect of crucible contamination was investigated and found to result in doping the system to suitable levels for thermoelectric applications. The system has been demonstrated as a suitable high temperature p-type thermoelectric material exhibiting high power factors, >3000 μW/m K{sup 2}. Seebeck coefficients of the system are on the order of +300 μV/K and electrical conductivities of 2.8 × 10{sup 4} S/m at the optimum operating temperature. The best composition, 0.9 at% W/9.3 at% Ge, achieved a figure of merit comparable to RTG values over the temperature range of interest. The results suggest that W addition can reduce the use of expensive Ge component of the alloy. Reported are the details of processing conditions, microstructure development, and temperature dependent thermoelectric properties. The material system was stable at the temperatures required for NASA’s radioisotope thermoelectric generators.

  2. Mechanical properties of thermoelectric n-type magnesium silicide synthesized employing in situ spark plasma reaction sintering

    Science.gov (United States)

    Muthiah, Saravanan; Singh, R. C.; Pathak, B. D.; Dhar, Ajay

    2017-07-01

    Thermoelectric devices employing magnesium silicide (Mg2Si) offer an inexpensive and non-toxic solution for green energy generation compared to other existing conventional thermoelectric materials in the mid-temperature range. However, apart from the thermoelectric performance, their mechanical properties are equally important in order to avoid the catastrophic failure of their modules during actual operation. In the present study, we report the synthesis of Mg2Si co-doped with Bi and Sb employing in situ spark plasma reaction sintering and investigate its broad range of mechanical properties. The mechanical properties of the sintered co-doped Mg2Si suggest a significantly enhanced value of hardness ~5.4  ±  0.2 GPa and an elastic modulus ~142.5  ±  6 GPa with a fracture toughness of ~1.71  ±  0.1 MPa  √m. The thermal shock resistance, which is one of the most vital parameter for designing thermoelectric devices, was found to be ~300 W m-1, which is higher than most of the other existing state-of-the-art mid-temperature thermoelectric materials. The friction and wear characteristics of sintered co-doped Mg2Si have been reported for the first time, in order to realize the sustainability of their thermoelectric modules under actual hostile environmental conditions.

  3. Validation, Optimization and Simulation of a Solar Thermoelectric Generator Model

    Science.gov (United States)

    Madkhali, Hadi Ali; Hamil, Ali; Lee, HoSung

    2017-12-01

    This study explores thermoelectrics as a viable option for small-scale solar thermal applications. Thermoelectric technology is based on the Seebeck effect, which states that a voltage is induced when a temperature gradient is applied to the junctions of two differing materials. This research proposes to analyze, validate, simulate, and optimize a prototype solar thermoelectric generator (STEG) model in order to increase efficiency. The intent is to further develop STEGs as a viable and productive energy source that limits pollution and reduces the cost of energy production. An empirical study (Kraemer et al. in Nat Mater 10:532, 2011) on the solar thermoelectric generator reported a high efficiency performance of 4.6%. The system had a vacuum glass enclosure, a flat panel (absorber), thermoelectric generator and water circulation for the cold side. The theoretical and numerical approach of this current study validated the experimental results from Kraemer's study to a high degree. The numerical simulation process utilizes a two-stage approach in ANSYS software for Fluent and Thermal-Electric Systems. The solar load model technique uses solar radiation under AM 1.5G conditions in Fluent. This analytical model applies Dr. Ho Sung Lee's theory of optimal design to improve the performance of the STEG system by using dimensionless parameters. Applying this theory, using two cover glasses and radiation shields, the STEG model can achieve a highest efficiency of 7%.

  4. Characterization of thermoelectric devices by laser induced Seebeck electromotive force (LIS-EMF) measurement

    Energy Technology Data Exchange (ETDEWEB)

    Lopez, Luis-David Patino [Universite de Bordeaux 1, Centre de Physique Moleculaire Optique et Hertzienne, 351, cours de la liberation, 33405 Talence (France); Dilhaire, Stefan [Universite de Bordeaux 1, Centre de Physique Moleculaire Optique et Hertzienne, 351, cours de la liberation, 33405 Talence (France); Grauby, Stephane [Universite de Bordeaux 1, Centre de Physique Moleculaire Optique et Hertzienne, 351, cours de la liberation, 33405 Talence (France); Salhi, M Amine [Universite de Bordeaux 1, Centre de Physique Moleculaire Optique et Hertzienne, 351, cours de la liberation, 33405 Talence (France); Ezzahri, Younes [Universite de Bordeaux 1, Centre de Physique Moleculaire Optique et Hertzienne, 351, cours de la liberation, 33405 Talence (France); Claeys, Wilfrid [Universite de Bordeaux 1, Centre de Physique Moleculaire Optique et Hertzienne, 351, cours de la liberation, 33405 Talence (France); Batsale, Jean-Christophe [Laboratoire TREFLE, Esplanade des Arts et Metiers, 33405 Talence Cedex (France)

    2005-05-21

    An in-depth study related to a new method of characterizing properties in thermoelectrics is proposed in this paper. This technique is appropriate for single or multi-layered thermoelectric devices. A modulated laser beam is used as a heater in order to generate a Seebeck electromotive force (EMF). The laser beam, line shaped, can be focused at any location along the sample surface, allowing spatially resolved measurements. Seebeck EMF measurements, associated with a versatile model based on the thermal quadrupoles method, allow determination of the sample Seebeck EMF profile and identifying of the sample thermal contact resistances, and should be useful for identification of devices and material thermoelectric properties.

  5. Characterization of thermoelectric devices by laser induced Seebeck electromotive force (LIS-EMF) measurement

    International Nuclear Information System (INIS)

    Lopez, Luis-David Patino; Dilhaire, Stefan; Grauby, Stephane; Salhi, M Amine; Ezzahri, Younes; Claeys, Wilfrid; Batsale, Jean-Christophe

    2005-01-01

    An in-depth study related to a new method of characterizing properties in thermoelectrics is proposed in this paper. This technique is appropriate for single or multi-layered thermoelectric devices. A modulated laser beam is used as a heater in order to generate a Seebeck electromotive force (EMF). The laser beam, line shaped, can be focused at any location along the sample surface, allowing spatially resolved measurements. Seebeck EMF measurements, associated with a versatile model based on the thermal quadrupoles method, allow determination of the sample Seebeck EMF profile and identifying of the sample thermal contact resistances, and should be useful for identification of devices and material thermoelectric properties

  6. Numerical Study on the Thermal Stress and its Formation Mechanism of a Thermoelectric Device

    Science.gov (United States)

    Pan, Tao; Gong, Tingrui; Yang, Wei; Wu, Yongjia

    2018-06-01

    The strong thermo-mechanical stress is one of the most critical failure mechanisms that affect the durability of thermoelectric devices. In this study, numerical simulations on the formation mechanism of the maximum thermal stress inside the thermoelectric device have been performed by using finite element method. The influences of the material properties and the thermal radiation on the thermal stress have been examined. The results indicate that the maximum thermal stress was located at the contact position between the two materials and occurred due to differential thermal expansions and displacement constraints of the materials. The difference in the calculated thermal stress value between the constant and the variable material properties was between 3% and 4%. At a heat flux of 1 W·cm-2 and an emissivity of 0.5, the influence of the radiation heat transfer on the thermal stress was only about 5%; however, when the heat flux was 20 W·cm-2 and the emissivity was 0.7, the influence of the radiation heat transfer was more than 30%.

  7. Dynamic thermoelectricity in uniform bipolar semiconductor

    Energy Technology Data Exchange (ETDEWEB)

    Volovichev, I.N., E-mail: vin@ire.kharkov.ua

    2016-07-01

    The theory of the dynamic thermoelectric effect has been developed. The effect lies in an electric current flowing in a closed circuit that consists of a uniform bipolar semiconductor, in which a non-uniform temperature distribution in the form of the traveling wave is created. The calculations are performed for the one-dimensional model in the quasi-neutrality approximation. It was shown that the direct thermoelectric current prevails, despite the periodicity of the thermal excitation, the circuit homogeneity and the lack of rectifier properties of the semiconductor system. Several physical reasons underlining the dynamic thermoelectric effect are found. One of them is similar to the Dember photoelectric effect, its contribution to the current flowing is determined by the difference in the electron and hole mobilities, and is completely independent of the carrier Seebeck coefficients. The dependence of the thermoelectric short circuit current magnitude on the semiconductor parameters, as well as on the temperature wave amplitude, length and velocity is studied. It is shown that the magnitude of the thermoelectric current is proportional to the square of the temperature wave amplitude. The dependence of the thermoelectric short circuit current on the temperature wave length and velocity is the nonmonotonic function. The optimum values for the temperature wave length and velocity, at which the dynamic thermoelectric effect is the greatest, have been deduced. It is found that the thermoelectric short circuit current changes its direction with decreasing the temperature wave length under certain conditions. The prospects for the possible applications of the dynamic thermoelectric effect are also discussed.

  8. Analysis and Experimental Investigation of Optimum Design of Thermoelectric Cooling/Heating System for Car Seat Climate Control (CSCC)

    Science.gov (United States)

    Elarusi, Abdulmunaem; Attar, Alaa; Lee, HoSung

    2018-02-01

    The optimum design of a thermoelectric system for application in car seat climate control has been modeled and its performance evaluated experimentally. The optimum design of the thermoelectric device combining two heat exchangers was obtained by using a newly developed optimization method based on the dimensional technique. Based on the analytical optimum design results, commercial thermoelectric cooler and heat sinks were selected to design and construct the climate control heat pump. This work focuses on testing the system performance in both cooling and heating modes to ensure accurate analytical modeling. Although the analytical performance was calculated using the simple ideal thermoelectric equations with effective thermoelectric material properties, it showed very good agreement with experiment for most operating conditions.

  9. Calculation of Nonlinear Thermoelectric Coefficients of InAs1-xSbx Using Monte Carlo Method

    Energy Technology Data Exchange (ETDEWEB)

    Sadeghian, RB; Bahk, JH; Bian, ZX; Shakouri, A

    2011-12-28

    It was found that the nonlinear Peltier effect could take place and increase the cooling power density when a lightly doped thermoelectric material is under a large electrical field. This effect is due to the Seebeck coefficient enhancement from an electron distribution far from equilibrium. In the nonequilibrium transport regime, the solution of the Boltzmann transport equation in the relaxation-time approximation ceases to apply. The Monte Carlo method, on the other hand, proves to be a capable tool for simulation of semiconductor devices at small scales as well as thermoelectric effects with local nonequilibrium charge distribution. InAs1-xSb is a favorable thermoelectric material for nonlinear operation owing to its high mobility inherited from the binary compounds InSb and InAs. In this work we report simulation results on the nonlinear Peltier power of InAs1-xSb at low doping levels, at room temperature and at low temperatures. The thermoelectric power factor in nonlinear operation is compared with the maximum value that can be achieved with optimal doping in the linear transport regime.

  10. Tetradymites as thermoelectrics and topological insulators

    Science.gov (United States)

    Heremans, Joseph P.; Cava, Robert J.; Samarth, Nitin

    2017-10-01

    Tetradymites are M2X3 compounds — in which M is a group V metal, usually Bi or Sb, and X is a group VI anion, Te, Se or S — that crystallize in a rhombohedral structure. Bi2Se3, Bi2Te3 and Sb2Te3 are archetypical tetradymites. Other mixtures of M and X elements produce common variants, such as Bi2Te2Se. Because tetradymites are based on heavy p-block elements, strong spin-orbit coupling greatly influences their electronic properties, both on the surface and in the bulk. Their surface electronic states are a cornerstone of frontier work on topological insulators. The bulk energy bands are characterized by small energy gaps, high group velocities, small effective masses and band inversion near the centre of the Brillouin zone. These properties are favourable for high-efficiency thermoelectric materials but make it difficult to obtain an electrically insulating bulk, which is a requirement of topological insulators. This Review outlines recent progress made in bulk and thin-film tetradymite materials for the optimization of their properties both as thermoelectrics and as topological insulators.

  11. Thermoelectric performance of tellurium-reduced quaternary p-type lead–chalcogenide composites

    International Nuclear Information System (INIS)

    Aminorroaya Yamini, Sima; Wang, Heng; Gibbs, Zachary M.; Pei, Yanzhong; Mitchell, David R.G.; Dou, Shi Xue; Snyder, G. Jeffrey

    2014-01-01

    Graphical abstract: - Abstract: A long-standing technological challenge to the widespread application of thermoelectric generators is obtaining high-performance thermoelectric materials from abundant elements. Intensive study on PbTe alloys has resulted in a high figure of merit for the single-phase ternary PbTe–PbSe system through band structure engineering, and the low thermal conductivity achieved due to nanostructuring leads to high thermoelectric performance for ternary PbTe–PbS compounds. Recently, the single-phase p-type quaternary PbTe–PbSe–PbS alloys have been shown to provide thermoelectric performance superior to the binary and ternary lead chalcogenides. This occurs via tuning of the band structure and from an extraordinary low thermal conductivity resulting from high-contrast atomic mass solute atoms. Here, we present the thermoelectric efficiency of nanostructured p-type quaternary PbTe–PbSe–PbS composites and compare the results with corresponding single-phase quaternary lead chalcogenide alloys. We demonstrate that the very low lattice thermal conductivity achieved is attributed to phonon scattering at high-contrast atomic mass solute atoms rather than from the contribution of secondary phases. This results in a thermoelectric efficiency of ∼1.4 over a wide temperature range (650–850 K) in a p-type quaternary (PbTe) 0.65 (PbSe) 0.1 (PbS) 0.25 composite that is lower than that of single-phase (PbTe) 0.85 (PbSe) 0.1 (PbS) 0.05 alloy without secondary phases

  12. Radioisotope thermoelectric generator licensed hardware package and certification tests

    International Nuclear Information System (INIS)

    Goldmann, L.H.; Averette, H.S.

    1994-01-01

    This paper presents the Licensed Hardware package and the Certification Test portions of the Radioisotope Thermoelectric Generator Transportation System. This package has been designed to meet those portions of the Code of Federal Regulations (10 CFR 71) relating to ''Type B'' shipments of radioactive materials. The detailed information for the anticipated license is presented in the safety analysis report for packaging, which is now in process and undergoing necessary reviews. As part of the licensing process, a full-size Certification Test Article unit, which has modifications slightly different than the Licensed Hardware or production shipping units, is used for testing. Dimensional checks of the Certification Test Article were made at the manufacturing facility. Leak testing and drop testing were done at the 300 Area of the US Department of Energy's Hanford Site near Richland, Washington. The hardware includes independent double containments to prevent the environmental spread of 238 Pu, impact limiting devices to protect portions of the package from impacts, and thermal insulation to protect the seal areas from excess heat during accident conditions. The package also features electronic feed-throughs to monitor the Radioisotope Thermoelectric Generator's temperature inside the containment during the shipment cycle. This package is designed to safely dissipate the typical 4500 thermal watts produced in the largest Radioisotope Thermoelectric Generators. The package also contains provisions to ensure leak tightness when radioactive materials, such as a Radioisotope Thermoelectric Generator for the Cassini Mission, planned for 1997 by the National Aeronautics and Space Administration, are being prepared for shipment. These provisions include test ports used in conjunction with helium mass spectrometers to determine seal leakage rates of each containment during the assembly process

  13. Impact of thermoelectric phenomena on phase-change memory performance metrics and scaling

    International Nuclear Information System (INIS)

    Lee, Jaeho; Asheghi, Mehdi; Goodson, Kenneth E

    2012-01-01

    The coupled transport of heat and electrical current, or thermoelectric phenomena, can strongly influence the temperature distribution and figures of merit for phase-change memory (PCM). This paper simulates PCM devices with careful attention to thermoelectric transport and the resulting impact on programming current during the reset operation. The electrothermal simulations consider Thomson heating within the phase-change material and Peltier heating at the electrode interface. Using representative values for the Thomson and Seebeck coefficients extracted from our past measurements of these properties, we predict a cell temperature increase of 44% and a decrease in the programming current of 16%. Scaling arguments indicate that the impact of thermoelectric phenomena becomes greater with smaller dimensions due to enhanced thermal confinement. This work estimates the scaling of this reduction in programming current as electrode contact areas are reduced down to 10 nm × 10 nm. Precise understanding of thermoelectric phenomena and their impact on device performance is a critical part of PCM design strategies. (paper)

  14. Enhancement in figure-of-merit with superlattices structures for thin-film thermoelectric devices

    Energy Technology Data Exchange (ETDEWEB)

    Venkatasubramanian, R; Colpitts, T

    1997-07-01

    Thin-film superlattice (SL) structures in thermoelectric materials are shown to be a promising approach to obtaining an enhanced figure-of-merit, ZT, compared to conventional, state-of-the-art bulk alloyed materials. In this paper the authors describe experimental results on Bi{sub 2}Te{sub 3}/Sb{sub 2}Te{sub 3} and Si/Ge SL structures, relevant to thermoelectric cooling and power conversion, respectively. The short-period Bi{sub 2}Te{sub 3} and Si/Ge SL structures appear to indicate reduced thermal conductivities compared to alloys of these materials. From the observed behavior of thermal conductivity values in the Bi{sub 2}Te{sub 3}/Sb{sub 2}Te{sub 3} SL structures, a distinction is made where certain types of periodic structures may correspond to an ordered alloy rather than an SL, and therefore, do not offer a significant reduction in thermal conductivity values. The study also indicates that SL structures, with little or weak quantum-confinement, also offer an improvement in thermoelectric power factor over conventional alloys. They present power factor and electrical transport data in the plane of the SL interfaces to provide preliminary support for the arguments on reduced alloy scattering and impurity scattering in Bi{sub 2}Te{sub 3}/Sb{sub 2}Te{sub 3} and Si/Ge SL structures. These results, though tentative due to the possible role of the substrate and the developmental nature of the 3-{omega} method used to determine thermal conductivity values, suggest that the short-period SL structures potentially offer factorial improvements in the three-dimensional figure-of-merit (ZT3D) compared to current state-of-the-art bulk alloys. An approach to a thin-film thermoelectric device called a Bipolarity-Assembled, Series-Inter-Connected Thin-Film Thermoelectric Device (BASIC-TFTD) is introduced to take advantage of these thin-film SL structures.

  15. Designing and testing the optimum design of automotive air-to-air thermoelectric air conditioner (TEAC) system

    International Nuclear Information System (INIS)

    Attar, Alaa; Lee, HoSung

    2016-01-01

    Highlights: • The optimum design of automotive thermoelectric AC system is proposed. • It is optimized by combining the thermal isolation and the dimensionless methods. • An experiment is conducted to validate the analytical design. - Abstract: The current project is discussing the optimization of counter flow air-to-air thermoelectric air conditioners (TEAC) system. Previous work showed an analytical model with experimental validation of a unit cell of TEAC system. However, the focus of this work is to simulate the optimum design of a whole TEAC system from given inlet parameters (i.e., hot and cold air mass flow rates and ambient temperatures). The analytical model was built by combining an optimal design method with dimensional analysis, which was recently developed, and the thermal isolation method in order to optimize the thermoelectric parameters (i.e., electrical current supplied and the number of thermocouples or the geometric factor, simultaneously). Moreover, based on the designed model, an experiment was conducted in order to study the accuracy of the analytical model. Even though the analytical model was built based on the thermoelectric ideal equations, it shows a good agreement with the experiment. This agreement was mainly a result of the use of the thermoelectric effective material properties which are obtained from the measured maximum thermoelectric module parameters. Since the experiment validate the analytical model, this model provides uncomplicated method to study the optimum design at given inputs.

  16. Design of thermoelectrically highly efficient Heusler compounds using phase separations and nano-composites under an economic point of view

    Science.gov (United States)

    Balke, Benjamin

    Half-Heusler (HH) compounds are one of the most promising candidates for thermoelectric materials for automotive and industrial waste heat recovery applications. In this talk, I will give an overview about our recent investigations of phase separations in HH thermoelectrics, focusing on the ternary system TiNiSn-ZrNiSn-HfNiSn. I will show how we adapted this knowledge to design a p-type HH compound which exhibits a ZT that is increased by 130% compared to the best published bulk p-type Heusler. I will also present how we used the phase separation to design thermoelectric highly efficient nano-composites of different single-phase materials. Since the price for Hafnium doubled within the last year, our research focused on the design of HH compounds without Hafnium. I will present a very recent calculation on ZT per Euro and efficiency per Euro for various materials followed by our latest very promising results for n-type Heusler compunds without Hafnium resulting in 20 times higher ZT/Euro values. These results strongly underline the importance of phase separations as a powerful tool for designing highly efficient materials for thermoelectric applications that fulfill the industrial demands for a thermoelectric converter. The author gratefully acknowledges financial support by the thermoHEUSLER2 Project (Project No. 19U15006F) of the German Federal Ministry of Economics and Technology (BMWi).

  17. PV-hybrid and thermoelectric collectors

    Energy Technology Data Exchange (ETDEWEB)

    Rockendorf, G.; Sillmann, R. [Institut fuer Solarenergieforschung GmbH, Emmerthal (Germany); Podlowski, L.; Litzenburger, B. [SolarWerk GmbH, Teltow (Germany)

    1999-07-01

    Two different principles of thermoelectric cogeneration solar collectors have been realized and investigated. Concerning the first principle, the thermoelectric collector (TEC) delivers electricity indirectly by first producing heat and subsequently generating electricity by means of a thermoelectric generator. Concerning the second principle, the photovoltaic-hybrid collector (PVHC) uses photovoltaic cells, which are cooled by a liquid heat-transfer medium. The characteristics of both collector types are described. Simulation modules have been developed and implemented in TRNSYS 14.1 (1994), in order to simulate their behaviour in typical domestic hot-water systems. The discussion of the results shows that the electric output of the PV-hybrid collector is significantly higher than that of the thermoelectric collector. (author)

  18. Preparation and thermoelectric properties of RF co-sputtered CoSb{sub 3} skutteruddite thin films

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, Aziz [University of Science and Technology, Daejeon (Korea, Republic of); Han, Seungwoo [Korea Institute of Machinery and Materials, Daejeon (Korea, Republic of); University of Science and Technology, Daejeon (Korea, Republic of)

    2014-11-15

    Various skutterudites have been under investigation because of their potential application in thermoelectric materials and devices. These studies indicate that bulk materials with a skutterudite type structure show reasonable thermoelectric behaviors at elevated temperatures, which make them suitable for high-temperature thermoelectric applications. The results of thermoelectric-property measurements on skutterudite-phase CoSb{sub 3} thin films are presented in this study in order to extend the bulk material concept to micro-device applications by using thin film deposition technology. Thin films are deposited on oxidized silicon substrates by using the RF co-sputtering method. The film's composition is found to depend strongly on the deposition conditions. The temperature at which the deposited films transition from an amorphous state to a crystalline state has been reported to be about 153 .deg. C. Therefore, some experiments are performed with the substrate temperature kept at 200 .deg. C to obtain polycrystalline films. The crystal structure of the film is evaluated by using x-ray diffraction (XRD) measurements. Energy dispersive spectroscopy (EDS) is used to determine the film's composition whereas the surface morphology and the thickness are investigated and measured by using scanning electron microscopy (SEM). Finally, the thermoelectric properties, namely, the electrical resistivity and the Seebeck coefficient, are used to calculate the power factor of the deposited thin films and, their variations with temperature are measured. We report a maximum power factor of 0.41 mW/mK{sup 2} for the film deposited at a 200 .deg. C substrate temperature.

  19. Effect of ball milling time on thermoelectric properties of bismuth telluride nanomaterials

    Science.gov (United States)

    Khade, Poonam; Bagwaiya, Toshi; Bhattacharaya, Shovit; Singh, Ajay; Jha, Purushottam; Shelke, Vilas

    2018-04-01

    The effect of different milling time on thermoelectric properties of bismuth telluride (Bi2Te3) was investigated. The nanomaterial was prepared by varying the ball milling time and followed by hot press sintering. The crystal structure and phase formation were verified by X-ray diffraction and Raman Spectroscopy. The experimental results show that electrical conductivity increases whereas thermal conductivity decreases with increasing milling time. The negative sign of seebeck coefficient indicate the n-type nature with majority charge carriers of electrons. A maximum figure of merit about 0.55 is achieved for l5hr ball milled Bi2Te3 sample. The present study demonstrates the simple and cost-effective method for synthesis of Bi2Te3 thermoelectric material at large scale thermoelectric applications.

  20. Effect of high-temperature annealing on the microstructure and thermoelectric properties of GaP doped SiGe. M.S. Thesis

    Science.gov (United States)

    Draper, Susan L.

    1987-01-01

    Annealing of GaP doped SiGe will significantly alter the thermoelectric properties of the material resulting in increased performance as measured by the figure of merit Z and the power factor P. The microstructures and corresponding thermoelectric properties after annealing in the 1100 to 1300 C temperature range have been examined to correlate performance improvement with annealing history. The figure of merit and power factor were both improved by homogenizing the material and limiting the amount of cross-doping. Annealing at 1215 C for 100 hr resulted in the best combination of thermoelectric properties with a resultant figure of merit exceeding 1x10 to the -3 deg C to the -1 and a power factor of 44 microW/cm/deg C sq for the temperature range of interest for space power: 400 to 1000 C.

  1. Roles of Cu in the Enhanced Thermoelectric Properties in Bi0.5Sb1.5Te3

    Directory of Open Access Journals (Sweden)

    Feng Hao

    2017-03-01

    Full Text Available Recently, Cu-containing p-type Bi0.5Sb1.5Te3 materials have shown high thermoelectric performances and promising prospects for practical application in low-grade waste heat recovery. However, the position of Cu in Bi0.5Sb1.5Te3 is controversial, and the roles of Cu in the enhancement of thermoelectric performance are still not clear. In this study, via defects analysis and stability test, the possibility of Cu intercalation in p-type Bi0.5Sb1.5Te3 materials has been excluded, and the position of Cu is identified as doping at the Sb sites. Additionally, the effects of Cu dopants on the electrical and thermal transport properties have been systematically investigated. Besides introducing additional holes, Cu dopants can also significantly enhance the carrier mobility by decreasing the Debye screen length and weakening the interaction between carriers and phonons. Meanwhile, the Cu dopants interrupt the periodicity of lattice vibration and bring stronger anharmonicity, leading to extremely low lattice thermal conductivity. Combining the suppression on the intrinsic excitation, a high thermoelectric performance—with a maximum thermoelectric figure of merit of around 1.4 at 430 K—has been achieved in Cu0.005Bi0.5Sb1.495Te3, which is 70% higher than the Bi0.5Sb1.5Te3 matrix.

  2. Thermoelectric PbTe thin film for superresolution optical data storage

    International Nuclear Information System (INIS)

    Lee, Hyun Seok; Cheong, Byung-ki; Lee, Taek Sung; Lee, Kyeong Seok; Kim, Won Mok; Lee, Jae Won; Cho, Sung Ho; Youl Huh, Joo

    2004-01-01

    To find its practical use in ultrahigh density optical data storage, superresolution (SR) technique needs a material that can render a high SR capability at no cost of durability against repeated readout and write. Thermoelectric materials appear to be promising candidates due to their capability of yielding phase-change-free thermo-optic changes. A feasibility study was carried out with PbTe for its large thermoelectric coefficient and high stability over a wide temperature range as a crystalline single phase. Under exposure to pulsed red light, the material was found to display positive, yet completely reversible changes of optical transmittance regardless of laser power, fulfilling basic requirements for SR readout and write. The material was also shown to have a high endurance against repeated static laser heating of up to 10 6 -10 7 cycles tested. A read only memory disk with a PbTe SR layer led to the carrier to noise ratio value of 47 dB at 3.5 mW for 0.25 μm pit; below the optical resolution limit (∼0.27 μm) of the tester

  3. Dismantling and chemical characterization of spent Peltier thermoelectric devices for antimony, bismuth and tellurium recovery.

    Science.gov (United States)

    Balva, Maxime; Legeai, Sophie; Garoux, Laetitia; Leclerc, Nathalie; Meux, Eric

    2017-04-01

    Major uses of thermoelectricity concern refrigeration purposes, using Peltier devices, mainly composed of antimony, bismuth and tellurium. Antimony was identified as a critical raw material by EU and resources of bismuth and tellurium are not inexhaustible, so it is necessary to imagine the recycling of thermoelectric devices. That for, a complete characterization is needed, which is the aim of this work. Peltier devices were manually dismantled in three parts: the thermoelectric legs, the alumina plates on which remain the electrical contacts and the silicone paste used to connect the plates. The characterization was performed using five Peltier devices. It includes mass balances of the components, X-ray diffraction analysis of the thermoelectric legs and elemental analysis of each part of the device. It appears that alumina represents 45% of a Peltier device in weight. The electrical contacts are mainly composed of copper and tin, and the thermoelectric legs of bismuth, tellurium and antimony. Thermoelectric legs appear to be Se-doped Bi 2 Te 3 and (Bi 0,5 Sb 1,5 )Te 3 for n type and p type semiconductors, respectively. This work shows that Peltier devices can be considered as a copper ore and that thermoelectric legs contain high amounts of bismuth, tellurium and antimony compared to their traditional resources.

  4. A note on the electrochemical nature of the thermoelectric power

    Science.gov (United States)

    Apertet, Y.; Ouerdane, H.; Goupil, C.; Lecoeur, Ph.

    2016-04-01

    While thermoelectric transport theory is well established and widely applied, it is not always clear in the literature whether the Seebeck coefficient, which is a measure of the strength of the mutual interaction between electric charge transport and heat transport, is to be related to the gradient of the system's chemical potential or to the gradient of its electrochemical potential. The present article aims to clarify the thermodynamic definition of the thermoelectric coupling. First, we recall how the Seebeck coefficient is experimentally determined. We then turn to the analysis of the relationship between the thermoelectric power and the relevant potentials in the thermoelectric system: As the definitions of the chemical and electrochemical potentials are clarified, we show that, with a proper consideration of each potential, one may derive the Seebeck coefficient of a non-degenerate semiconductor without the need to introduce a contact potential as seen sometimes in the literature. Furthermore, we demonstrate that the phenomenological expression of the electrical current resulting from thermoelectric effects may be directly obtained from the drift-diffusion equation.

  5. Thermoelectric generator

    International Nuclear Information System (INIS)

    Purdy, D.L.

    1978-01-01

    The main components of a thermoelectric generator are housed in an evacuated cylindrical vessel. In the middle of it there is the radioactive heat source, e.g. 90 Sr or 238 Pu, enclosed by a gamma radiation shield. This one is surrounded by a heat-insulating screen from getter material or indicidual sheets of titanium. In the bottom of the screen there are arranged several thermocouples on a circle. The thermocouples themselves are contained within casings sealed gas-tight and filled with an inert gas, e.g. argon. By separating the internal space of the generator vessel from the thermocouple casings, made of e.g. n- respectively p-doped lead telluride cylinders, for both the optimal gas state may be obtained. (DG) [de

  6. Solution synthesis of telluride-based nano-barbell structures coated with PEDOT:PSS for spray-printed thermoelectric generators

    Science.gov (United States)

    Bae, Eun Jin; Kang, Young Hun; Jang, Kwang-Suk; Lee, Changjin; Cho, Song Yun

    2016-05-01

    Solution-processable telluride-based heterostructures coated with poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (Te-Bi2Te3/PEDOT:PSS) were synthesized through a solution-phase reaction at low temperatures. The water-based synthesis yielded PEDOT:PSS-coated Te-Bi2Te3 nano-barbell structures with a high Seebeck coefficient that can be stably dispersed in water. These hybrid solutions were deposited onto a substrate by the spray-printing method to prepare thermoelectric generators. The thermoelectric properties of the Te-Bi2Te3/PEDOT:PSS hybrid films were significantly enhanced by a simple acid treatment due to the increased electrical conductivity, and the power factor of those materials can be effectively tuned over a wide range depending on the acid concentration of the treatment. The power factors of the synthesized Te-Bi2Te3/PEDOT:PSS hybrids were optimized to 60.05 μW m-1 K-2 with a Seebeck coefficient of 93.63 μV K-1 and an electrical conductivity of 69.99 S cm-1. The flexible thermoelectric generator fabricated by spray-printing Te-Bi2Te3/PEDOT:PSS hybrid solutions showed an open-circuit voltage of 1.54 mV with six legs at ΔT = 10 °C. This approach presents the potential for realizing printing-processable hybrid thermoelectric materials for application in flexible thermoelectric generators.Solution-processable telluride-based heterostructures coated with poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (Te-Bi2Te3/PEDOT:PSS) were synthesized through a solution-phase reaction at low temperatures. The water-based synthesis yielded PEDOT:PSS-coated Te-Bi2Te3 nano-barbell structures with a high Seebeck coefficient that can be stably dispersed in water. These hybrid solutions were deposited onto a substrate by the spray-printing method to prepare thermoelectric generators. The thermoelectric properties of the Te-Bi2Te3/PEDOT:PSS hybrid films were significantly enhanced by a simple acid treatment due to the increased electrical conductivity, and

  7. A holistic 3D finite element simulation model for thermoelectric power generator element

    International Nuclear Information System (INIS)

    Wu, Guangxi; Yu, Xiong

    2014-01-01

    Highlights: • Development of a holistic simulation model for the thermoelectric energy harvester. • Account for delta Seebeck coefficient and carrier charge densities variations. • Solution of thermo-electric coupling problem with finite element method. • Model capable of predicting phenomena not captured by traditional models. • A simulation tool for design of innovative TEM materials and structures. - Abstract: Harvesting the thermal energy stored in the ambient environment provides a potential sustainable energy source. Thermoelectric power generators have advantages of having no moving parts, being durable, and light-weighted. These unique features are advantageous for many applications (i.e., carry-on medical devices, embedded infrastructure sensors, aerospace, transportation, etc.). To ensure the efficient applications of thermoelectric energy harvesting system, the behaviors of such systems need to be fully understood. Finite element simulations provide important tools for such purpose. Although modeling the performance of thermoelectric modules has been conducted by many researchers, due to the complexity in solving the coupled problem, the influences of the effective Seebeck coefficient and carrier density variations on the performance of thermoelectric system are generally neglected. This results in an overestimation of the power generator performance under strong-ionization temperature region. This paper presents an advanced simulation model for thermoelectric elements that considers the effects of both factors. The mathematical basis of this model is firstly presented. Finite element simulations are then implemented on a thermoelectric power generator unit. The characteristics of the thermoelectric power generator and their relationship to its performance are discussed under different working temperature regions. The internal physics processes of the TEM harvester are analyzed from the results of computational simulations. The new model

  8. Effects of hydrostatic pressure on the thermoelectric properties of the ɛ-polytype of InSe, GaSe, and InGaSe2 semiconductor compounds: an ab initio study

    Science.gov (United States)

    Elsayed, H.; Olguín, D.; Cantarero, A.

    2017-12-01

    This work presents an ab initio study of the effects of hydrostatic pressure on the Seebeck coefficients and thermoelectric power factors of the ɛ-polytype of InSe, GaSe, and InGaSe2 semiconductor compounds. Our study is performed using the semi-classical Boltzmann theory and the rigid band approach. The electronic band structures of these materials are calculated using the full-potential linearized augmented plane-wave method. The obtained thermoelectric properties are discussed in terms of the results of the electronic structure calculations. As we will show, our calculated Seebeck coefficient values indicate that these materials are good alternatives to other well-studied thermoelectric systems.

  9. Development and Analysis of Hybrid Thermoelectric Refrigerator Systems

    Science.gov (United States)

    Saifizi, M.; Zakaria, M. S.; Yaacob, Sazali; Wan, Khairunizam

    2018-03-01

    Thermoelectric module (TEM) is a type of solid-state devices which has the capability to maintain the accuracy of small temperature variation application. In this study, a hybrid thermoelectric refrigerator system is introduced by utilizing TEMs; direct and air to air thermoelectric heat pump to cool down and maintain low temperature for vaccines storage. Two different materials which are aluminum and stainless steel are used as container in hybrid thermoelectric refrigerator (HTER) configuration to investigate the response of every system in transient and steady state mode. A proper temperature sensor calibration technique is implemented to make certain real time data acquisition of the systems are not affected very much from the noise generated. From step response analysis, it is indicated that HTER I (aluminum) has rapid settling time from transient to steady state than HTER II (stainless steel) since aluminum has better thermal conductivity as compared to stainless steel. It is found that HTER I is better in cooling capability with the same input current instead of HTER II which required a longer time to achieve steady state mode. Besides, in Pseudo Random Binary Sequence (PRBS) response analysis injected to both systems shows HTER I is very sensitive to current input as the sequence length of HTER I is shorter than HTER II. However both systems depict the varying temperature in the range of 4 oC due to differences in thermal conductivity of container.

  10. The single-crystal multinary compound Cu2ZnSnS4 as an environmentally friendly high-performance thermoelectric material

    Science.gov (United States)

    Nagaoka, Akira; Masuda, Taizo; Yasui, Shintaro; Taniyama, Tomoyasu; Nose, Yoshitaro

    2018-05-01

    We investigated the thermoelectric properties of high-quality p-type Cu2ZnSnS4 single crystals. This material showed two advantages: low thermal conductivity because of lattice scattering caused by the easily formed Cu/Zn disordered structure, and high conductivity because of high doping from changes to the composition. All samples showed a thermal conductivity of 3.0 W m‑1 K‑1 at 300 K, and the Cu-poor sample showed a conductivity of 7.5 S/cm at 300 K because of the high density of shallow-acceptor Cu vacancies. The figure of merit of the Cu-poor Cu2ZnSnS4 reached 0.2 at 400 K, which is 1.4–45 times higher than those of related compounds.

  11. Thermoelectric Effects under Adiabatic Conditions

    Directory of Open Access Journals (Sweden)

    George Levy

    2013-10-01

    Full Text Available This paper investigates not fully explained voltage offsets observed by several researchers during the measurement of the Seebeck coefficient of high Z materials. These offsets, traditionally attributed to faulty laboratory procedures, have proven to have an irreducible component that cannot be fully eliminated in spite of careful laboratory procedures. In fact, these offsets are commonly observed and routinely subtracted out of commercially available Seebeck measurement systems. This paper offers a possible explanation based on the spontaneous formation of an adiabatic temperature gradient in the presence of a force field. The diffusion-diffusion heat transport mechanism is formulated and applied to predict two new thermoelectric effects. The first is the existence of a temperature gradient across a potential barrier in a semiconductor and the second is the Onsager reciprocal of the first, that is, the presence of a measureable voltage that arises across a junction when the temperature gradient is forced to zero by a thermal clamp. Suggested future research includes strategies for utilizing the new thermoelectric effects.

  12. Electrical and thermoelectric properties of different compositions of Ge–Se–In thin films

    Energy Technology Data Exchange (ETDEWEB)

    Aly, K.A., E-mail: kamalaly2001@gmail.com [Physics Department, Faculty of Science and Arts Khulais, University of Jeddah (Saudi Arabia); Physics Department, Faculty of Science, Al-Azhar University, Assiut Branch, Assiut (Egypt); Dahshan, A., E-mail: adahshan73@gmail.com [Department of Physics, Faculty of Science, Port Said University, Port Said (Egypt); Department of Physics, Faculty of Science for Girls, King Khalid University, Abha (Saudi Arabia); Abbady, Gh. [Department of Physics, Faculty of Science, Assuit University, Assuit (Egypt); Saddeek, Y. [Physics Department, Faculty of Science, Al-Azhar University, Assiut Branch, Assiut (Egypt)

    2016-09-15

    The effect of temperature in the range of 300–450 K and the indium content on the electrical and thermoelectric properties of Ge{sub 20}Se{sub 80−x}In{sub x} (0.0≤x≤24 at%) chalcogenide glassy thin films have been studied. From dc electrical and thermoelectric measurements, it was observed that the activation energies for electrical conductivity (ΔE) and for thermoelectric (ΔE{sub s}) decrease while the conductivity (σ) and Seebeck coefficient (S) increase upon introducing In into the Ge–Se glasses. In contrast to the behavior obtained with Bi or Pb doping, In incorporated in Ge–Se does not lead to a p-to n-type conduction inversion. The power factor (P) which is strongly depends on both of the Seebeck coefficient and the electrical conductivity. According to the obtained results, the Ge{sub 20}Se{sub 80−x}In{sub x} films can be considered potential candidates for incurring high action thermoelectric materials.

  13. Thermoelectric Properties in the TiO2/SnO2 System

    Science.gov (United States)

    Dynys, F.; Sayir, A.; Sehirlioglu, A.; Berger, M.

    2009-01-01

    Nanotechnology has provided a new interest in thermoelectric technology. A thermodynamically driven process is one approach in achieving nanostructures in bulk materials. TiO2/SnO2 system exhibits a large spinodal region with exceptional stable phase separated microstructures up to 1400 C. Fabricated TiO2/SnO2 nanocomposites exhibit n-type behavior with Seebeck coefficients greater than -300 .V/K. Composites exhibit good thermal conductance in the range of 7 to 1 W/mK. Dopant additions have not achieved high electrical conductivity (<1000 S/m). Formation of oxygen deficient composites, TixSn1-xO2-y, can change the electrical conductivity by four orders of magnitude. Achieving higher thermoelectric ZT by oxygen deficiency is being explored. Seebeck coeffcient, thermal conductivity, electrical conductance and microstructure will be discussed in relation to composition and doping.

  14. Flexible and self-powered temperature-pressure dual-parameter sensors using microstructure-frame-supported organic thermoelectric materials.

    Science.gov (United States)

    Zhang, Fengjiao; Zang, Yaping; Huang, Dazhen; Di, Chong-an; Zhu, Daoben

    2015-09-21

    Skin-like temperature- and pressure-sensing capabilities are essential features for the next generation of artificial intelligent products. Previous studies of e-skin and smart elements have focused on flexible pressure sensors, whereas the simultaneous and sensitive detection of temperature and pressure with a single device remains a challenge. Here we report developing flexible dual-parameter temperature-pressure sensors based on microstructure-frame-supported organic thermoelectric (MFSOTE) materials. The effective transduction of temperature and pressure stimuli into two independent electrical signals permits the instantaneous sensing of temperature and pressure with an accurate temperature resolution of pressure-sensing sensitivity of up to 28.9 kPa(-1). More importantly, these dual-parameter sensors can be self-powered with outstanding sensing performance. The excellent sensing properties of MFSOTE-based devices, together with their unique advantages of low cost and large-area fabrication, make MFSOTE materials possess promising applications in e-skin and health-monitoring elements.

  15. High Performance Thermoelectric Materials Using Solution Phase Synthesis of Narrow Bandgap Core/Shell Quantum Dots Deposited Into Colloidal Crystal Thin Films

    National Research Council Canada - National Science Library

    2005-01-01

    Thermoelectrics is the science and technology associated with thermoelectric converters, that is, the generation of electrical power based on the Seebeck effect and refrigeration by the Peltier effect...

  16. Independent Power Generation in a Modern Electrical Substation Based on Thermoelectric Technology

    Science.gov (United States)

    Li, Z. M.; Zhao, Y. Q.; Liu, W.; Wei, B.; Qiu, M.; Lai, X. K.

    2017-05-01

    Because of many types of electrical equipment with high power in substations, the potentiality of energy conservation is quite large. From this viewpoint, thermoelectric materials may be chosen to produce electrical energy using the waste heat produced in substations. Hence, a thermoelectric generation system which can recycle the waste heat from electric transformers was proposed to improve the energy efficiency and reduce the burden of the oil cooling system. An experimental prototype was fabricated to perform the experiment and to verify the feasibility. The experimental results showed that the output power could achieve 16 W from waste heat of 900 W, and that the power conversion efficiency was approximately 1.8%. Therefore, power generation is feasible by using the waste heat from the transformers based on thermoelectric technology.

  17. Synthesis, thermal behavior and thermoelectric properties of disordered tellurides with structures derived from the rocksalt type

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, Thorsten

    2014-06-17

    GeBi{sub 2}Te{sub 4} is proposed as phase-change material. Nanostructures in metastable GeBi{sub 2}Te{sub 4} were obtained by high-pressure synthesis and thermal quenching, - depending on temperature and pressure different modifications were found. The differences in the electrical characteristics can be attributed to the variation of grain boundary concentration and the grain size distribution. Two synthesis approaches were used to prepare Ag{sub 3.4}In{sub 3.7}Sb{sub 76.4}Te{sub 16.5} bulk samples and studied with respect to their transport and thermal properties. A high pressure route to prepare thermoelectrics with low thermal conductivity was developed for AgIn{sub x}Sb{sub 1-x}Te{sub 2}. Disorder and and transport studies on In{sub 3}SbTe{sub 2} were performed using X-ray, neutron and electron diffraction measurements. Nanostructures in Te/Sb/Ge/Ag (TAGS) thermoelectric materials were induced by phase transitions associated with vacancy ordering. Further studies concerned solid solution series (GeTe){sub x}(LiSbTe{sub 2}){sub 2} (1 smaller or equal x smaller or equal 11) and their thermoelectric properties.

  18. Thermoelectric properties of high electron concentration materials under large temperature gradients

    International Nuclear Information System (INIS)

    Bulat, L.P.; Stefansky, V.A.

    1994-01-01

    Theoretical methods of investigating of transport properties in solids under large temperature gradients are grounded. The nonlinear and non-local expressions for current density and heat flow are obtained with degenerated of current carriers gas. A number of new effects with large temperature gradients have been tested. Use of large temperature gradients leads to the increasing of the thermoelectric figure of merit. copyright 1995 American Institute of Physics

  19. Thermal and stress analyses in thermoelectric generator with tapered and rectangular pin configurations

    International Nuclear Information System (INIS)

    Yilbas, Bekir Sami; Akhtar, S.S.; Sahin, A.Z.

    2016-01-01

    Thermal stress developed in thermoelectric generators is critical for long service applications. High temperature gradients, due to a large temperature difference across the junctions, causes excessive stress levels developed in the device pins and electrodes at the interfaces. In the present study, a thermoelectric generator with horizontal pin configuration is considered and thermal stress analysis in the device is presented. Ceramic wafer is considered to resemble the high temperature plate and copper electrodes are introduced at the pin junctions to reduce the electrical resistance between the pins and the high and low temperature junction plates during the operation. Finite element code is used to simulate temperature and stress fields in the thermoelectric generator. In the simulations, convection and radiation losses from the thermoelectric pins are considered and bismuth telluride pin material with and without tapering is incorporated. It is found that von Mises stress attains high values at the interface between the hot and cold junctions and the copper electrodes. Thermal stress developed in tapered pin configuration attains lower values than that of rectangular pin cross-section. - Highlights: • Different cold junction temperatures improves thermoelectric generator performance. • von Mises stress remains high across copper electrodes and hot junction ceramics. • von Mises stress reduces along pin length towards cold junction. • Pin tapering lowers stress levels in thermoelectric generator.

  20. A Low-Cost Production Method of FeSi2 Power Generation Thermoelectric Modules

    Science.gov (United States)

    Inoue, Hiroyuki; Kobayashi, Takahide; Kato, Masahiko; Yoneda, Seiji

    2016-03-01

    A method is proposed to reduce the production cost of power generation thermoelectric modules. FeSi2 is employed as the thermoelectric material because of its low cost, low environmental load, and oxidation resistance. The raw materials were prepared in the composition of Fe0.96Si2.1Co0.04 for n-type and Fe0.92Si2.1Mn0.08 for p-type, which were added with 0.5 wt.% Cu as the starting materials. They were sintered without pressure at 1446 K to be formed into elements. The Seebeck coefficient and resistivity at room temperature were determined to be -182 μV/K and 0.13 mΩm for n-type, and 338 μV/K and 1.13 mΩm for p-type, respectively. The brazing conditions of the direct joining between the element and the solder were examined. Pastes of BNi-6, BNi-7 or TB-608T were tried as the solder. TB-608T was useable for metallizing of insulation substrates and joining of thermoelectric elements in order to manufacture thermoelectric modules. The joining strength was determined to be 50 MPa between the alumina plate and the elements. No mechanical failure was observed in the modules after repetition of 10 or more exposures to a heat source of 670 K. No change was found in the internal resistance. The present production method will provide modules with high durability and low production cost, which will enable high-power multi-stage cascade modules at a reasonable cost.

  1. Inorganic nanostructure-organic polymer heterostructures useful for thermoelectric devices

    Energy Technology Data Exchange (ETDEWEB)

    See, Kevin C.; Urban, Jeffrey J.; Segalman, Rachel A.; Coates, Nelson E.; Yee, Shannon K.

    2017-11-28

    The present invention provides for an inorganic nanostructure-organic polymer heterostructure, useful as a thermoelectric composite material, comprising (a) an inorganic nanostructure, and (b) an electrically conductive organic polymer disposed on the inorganic nanostructure. Both the inorganic nanostructure and the electrically conductive organic polymer are solution-processable.

  2. Scientific report 1998; Rapport scientifique 1998

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-07-01

    The aim of this report is to outline the main developments of the ''Departement des Reacteurs Nucleaires'', (DRN) during the year 1998. DRN is one of the CEA Institution. This report is divided in three main parts: the DRN scientific programs, the scientific and technical publications (with abstracts in english) and economic data on staff, budget and communication. Main results of the Department, for the year 1998, are presented giving information on the reactors technology and safety, the neutronics, the transmutation and the hybrid systems, the dismantling and the sites improvement, the nuclear accidents, the nuclear matter transport, the thermonuclear fusion safety, the fuel cladding materials and radioactive waste control. (A.L.B.)

  3. Scientific report 1998; Rapport scientifique 1998

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-07-01

    The aim of this report is to outline the main developments of the ''Departement des Reacteurs Nucleaires'', (DRN) during the year 1998. DRN is one of the CEA Institution. This report is divided in three main parts: the DRN scientific programs, the scientific and technical publications (with abstracts in english) and economic data on staff, budget and communication. Main results of the Department, for the year 1998, are presented giving information on the reactors technology and safety, the neutronics, the transmutation and the hybrid systems, the dismantling and the sites improvement, the nuclear accidents, the nuclear matter transport, the thermonuclear fusion safety, the fuel cladding materials and radioactive waste control. (A.L.B.)

  4. Investigation of thermoelectric SiC ceramics for energy harvesting ...

    Indian Academy of Sciences (India)

    Utilizing thermoelectric technology to aerodynamic heat harvesting on the ... in terms of the computational fluid dynamics and the thermal conduction theory. ... It is shown that doping elements with good ... ous SiC materials, yet few experimental studies have been ... polymer-derived consolidated SiC-based ceramics, which.

  5. Microwave plasma synthesis of Si/Ge and Si/WSi2 nanoparticles for thermoelectric applications

    Science.gov (United States)

    Petermann, Nils; Schneider, Tom; Stötzel, Julia; Stein, Niklas; Weise, Claudia; Wlokas, Irenäus; Schierning, Gabi; Wiggers, Hartmut

    2015-08-01

    The utilization of microwave-based plasma systems enables a contamination-free synthesis of highly specific nanoparticles in the gas phase. A reactor setup allowing stable, long-term operation was developed with the support of computational fluid dynamics. This paper highlights the prospects of gas-phase plasma synthesis to produce specific materials for bulk thermoelectrics. Taking advantage of specific plasma reactor properties such as Coulomb repulsion in combination with gas temperatures considerably higher than 1000 K, spherical and non-aggregated nanoparticles of multiple compositions are accessible. Different strategies towards various nanostructured composites and alloys are discussed. It is shown that, based on doped silicon/germanium alloys and composites, thermoelectric materials with zT values up to almost unity can be synthesized in one step. First experimental results concerning silicon/tungsten silicide thermoelectrics applying the nanoparticle-in-alloy idea are presented indicating that this concept might work. However, it is found that tungsten silicides show a surprising sinter activity more than 1000 K below their melting temperature.

  6. Hydrogenated Nano-/Micro-Crystalline Silicon Thin-Films for Thermoelectrics

    Science.gov (United States)

    Acosta, E.; Wight, N. M.; Smirnov, V.; Buckman, J.; Bennett, N. S.

    2018-06-01

    Thermoelectric technology has not yet been able to reach full-scale market penetration partly because most commercial materials employed are scarce/costly, environmentally unfriendly and in addition provide low conversion efficiency. The necessity to tackle some of these hurdles leads us to investigate the suitability of n-type hydrogenated microcrystalline silicon (μc-Si: H) in the fabrication of thermoelectric devices, produced by plasma enhanced chemical vapour deposition (PECVD), which is a mature process of proven scalability. This study reports an approach to optimise the thermoelectric power factor (PF) by varying the dopant concentration by means of post-annealing without impacting film morphology, at least for temperatures below 550°C. Results show an improvement in PF of more than 80%, which is driven by a noticeable increase of carrier mobility and Seebeck coefficient in spite of a reduction in carrier concentration. A PF of 2.08 × 10-4 W/mK2 at room temperature is reported for n-type films of 1 μm thickness, which is in line with the best values reported in recent literature for similar structures.

  7. Hydrogenated Nano-/Micro-Crystalline Silicon Thin-Films for Thermoelectrics

    Science.gov (United States)

    Acosta, E.; Wight, N. M.; Smirnov, V.; Buckman, J.; Bennett, N. S.

    2017-11-01

    Thermoelectric technology has not yet been able to reach full-scale market penetration partly because most commercial materials employed are scarce/costly, environmentally unfriendly and in addition provide low conversion efficiency. The necessity to tackle some of these hurdles leads us to investigate the suitability of n-type hydrogenated microcrystalline silicon (μc-Si: H) in the fabrication of thermoelectric devices, produced by plasma enhanced chemical vapour deposition (PECVD), which is a mature process of proven scalability. This study reports an approach to optimise the thermoelectric power factor (PF) by varying the dopant concentration by means of post-annealing without impacting film morphology, at least for temperatures below 550°C. Results show an improvement in PF of more than 80%, which is driven by a noticeable increase of carrier mobility and Seebeck coefficient in spite of a reduction in carrier concentration. A PF of 2.08 × 10-4 W/mK2 at room temperature is reported for n-type films of 1 μm thickness, which is in line with the best values reported in recent literature for similar structures.

  8. Fabrication of Thermoelectric Devices Using Additive-Subtractive Manufacturing Techniques: Application to Waste-Heat Energy Harvesting

    Science.gov (United States)

    Tewolde, Mahder

    Thermoelectric generators (TEGs) are solid-state devices that convert heat directly into electricity. They are well suited for waste-heat energy harvesting applications as opposed to primary energy generation. Commercially available thermoelectric modules are flat, inflexible and have limited sizes available. State-of-art manufacturing of TEG devices relies on assembling prefabricated parts with soldering, epoxy bonding, and mechanical clamping. Furthermore, efforts to incorporate them onto curved surfaces such as exhaust pipes, pump housings, steam lines, mixing containers, reaction chambers, etc. require custom-built heat exchangers. This is costly and labor-intensive, in addition to presenting challenges in terms of space, thermal coupling, added weight and long-term reliability. Additive manufacturing technologies are beginning to address many of these issues by reducing part count in complex designs and the elimination of sub-assembly requirements. This work investigates the feasibility of utilizing such novel manufacturing routes for improving the manufacturing process of thermoelectric devices. Much of the research in thermoelectricity is primarily focused on improving thermoelectric material properties by developing of novel materials or finding ways to improve existing ones. Secondary to material development is improving the manufacturing process of TEGs to provide significant cost benefits. To improve the device fabrication process, this work explores additive manufacturing technologies to provide an integrated and scalable approach for TE device manufacturing directly onto engineering component surfaces. Additive manufacturing techniques like thermal spray and ink-dispenser printing are developed with the aim of improving the manufacturing process of TEGs. Subtractive manufacturing techniques like laser micromachining are also studied in detail. This includes the laser processing parameters for cutting the thermal spray materials efficiently by

  9. Optimized Characterization of Thermoelectric Generators for Automotive Application

    Science.gov (United States)

    Tatarinov, Dimitri; Wallig, Daniel; Bastian, Georg

    2012-06-01

    New developments in the field of thermoelectric materials bring the prospect of consumer devices for recovery of some of the waste heat from internal combustion engines closer to reality. Efficiency improvements are expected due to the development of high-temperature thermoelectric generators (TEG). In contrast to already established radioisotope thermoelectric generators, the temperature difference in automotive systems is not constant, and this imposes a set of specific requirements on the TEG system components. In particular, the behavior of the TEGs and interface materials used to link the heat flow from the heat source through the TEG to the heat sink must be examined. Due to the usage patterns of automobiles, the TEG will be subject to cyclic thermal loads, which leads to module degradation. Additionally, the automotive TEG will be exposed to an inhomogeneous temperature distribution, leading to inhomogeneous mechanical loads and reduced system efficiency. Therefore, a characterization rig is required to allow determination of the electrical, thermal, and mechanical properties of such high-temperature TEG systems. This paper describes a measurement setup using controlled adjustment of cold-side and warm-side temperatures as well as controlled feed-in of electrical power for evaluation of TEGs for application in vehicles with combustion engines. The temperature profile in the setup can be varied to simulate any vehicle usage pattern, such as the European standard driving cycle, allowing the power yield of the TEGs to be evaluated for the chosen cycle. The spatially resolved temperature distribution of a TEG system can be examined by thermal imaging. Hotspots or cracks on thermocouples of the TEGs and the thermal resistance of thermal interface materials can also be examined using this technology. The construction of the setup is briefly explained, followed by detailed discussion of the experimental results.

  10. THERMOELECTRIC PROPERTIES OF HOT-PRESSED p-TYPE Mg2Si0.3Sn0.7 SOLID SOLUTION

    Directory of Open Access Journals (Sweden)

    G. N. Isachenko

    2014-05-01

    Full Text Available It is shown that thermoelectric energy conversion which gives the possibility for utilizing a low potential heat is one of the ways for adoption of energy-saving technologies; and semiconductor materials with p-type and n-type conductivities having high thermoelectric figure of merit are necessary for operation of thermoelectric generators. The paper deals with possibility of usage of the p-Mg2Si0.3Sn0.7 solid solution (with a nanostructured modification as a couple for the well studied thermoelectric material based on n-Mg2Si-Mg2Sn. A technological scheme for fabrication of heavily doped Mg2Si0.3Sn0.7 solid solution of p-type by hot pressing from nanopowder is developed. The given technology has made it possible to reduce duration of a homogeneous material fabrication and has improved its physical and chemical properties. The samples were made by three ways: direct fusion for polycrystals fabrication; hot pressing from microparticles; nanostructuring, i.e. hot pressing from nanoparticles. By X-ray diffraction it is shown that sizes of structural elements in the fabricated samples are about 40 nm. The probe technique is used for measurement of electric conductivity and Seebeck coefficient. The stationary absolute method is used for measurement of thermal conductivity. Thermoelectric figure of merit is defined by measured values of kinetic coefficients in the temperatures range of 77 – 800 K. It was demonstrated, that electric conductivity, Seebeck coefficient and the power factor do not depend practically on a way of solid solution preparation. Thermal conductivity of samples pressed from nanoparticles has appeared to be higher, than of samples, obtained by direct fusion; i.e. in this case nanostructuring has not led to increase of thermoelectric figure of merit. The conclusion is drawn, that polycrystalline semiconductor Mg2Si0.3Sn0.7 can be used as a p-branch for a thermoelectric generator though nanostructuring has not led to the figure of