Thin-film thermoelectric devices with high room-temperature figures of merit
TL;DR: Th thin-film thermoelectric materials are reported that demonstrate a significant enhancement in ZT at 300 K, compared to state-of-the-art bulk Bi2Te3 alloys, and the combination of performance, power density and speed achieved in these materials will lead to diverse technological applications.
Abstract: Thermoelectric materials are of interest for applications as heat pumps and power generators. The performance of thermoelectric devices is quantified by a figure of merit, ZT, where Z is a measure of a material's thermoelectric properties and T is the absolute temperature. A material with a figure of merit of around unity was first reported over four decades ago, but since then-despite investigation of various approaches-there has been only modest progress in finding materials with enhanced ZT values at room temperature. Here we report thin-film thermoelectric materials that demonstrate a significant enhancement in ZT at 300 K, compared to state-of-the-art bulk Bi2Te3 alloys. This amounts to a maximum observed factor of approximately 2.4 for our p-type Bi2Te3/Sb2Te3 superlattice devices. The enhancement is achieved by controlling the transport of phonons and electrons in the superlattices. Preliminary devices exhibit significant cooling (32 K at around room temperature) and the potential to pump a heat flux of up to 700 W cm-2; the localized cooling and heating occurs some 23,000 times faster than in bulk devices. We anticipate that the combination of performance, power density and speed achieved in these materials will lead to diverse technological applications: for example, in thermochemistry-on-a-chip, DNA microarrays, fibre-optic switches and microelectrothermal systems.
Citations
More filters
TL;DR: Thermoelectric materials are solid-state energy converters whose combination of thermal, electrical, and semiconductor properties allows them to be used to convert waste heat into electricity or electrical power directly into cooling and heating.
Abstract: Thermoelectric materials are solid-state energy converters whose combination of thermal, electrical, and semiconducting properties allows them to be used to convert waste heat into electricity or electrical power directly into cooling and heating. These materials can be competitive with fluid-based systems, such as two-phase air-conditioning compressors or heat pumps, or used in smaller-scale applications such as in automobile seats, night-vision systems, and electrical-enclosure cooling. More widespread use of thermoelectrics requires not only improving the intrinsic energy-conversion efficiency of the materials but also implementing recent advancements in system architecture. These principles are illustrated with several proven and potential applications of thermoelectrics.
4,700 citations
TL;DR: Electrical transport measurements, coupled with microstructure studies and modeling, show that the ZT improvement is the result of low thermal conductivity caused by the increased phonon scattering by grain boundaries and defects, which makes these materials useful for cooling and power generation.
Abstract: The dimensionless thermoelectric figure of merit (ZT) in bismuth antimony telluride (BiSbTe) bulk alloys has remained around 1 for more than 50 years. We show that a peak ZT of 1.4 at 100°C can be achieved in a p-type nanocrystalline BiSbTe bulk alloy. These nanocrystalline bulk materials were made by hot pressing nanopowders that were ball-milled from crystalline ingots under inert conditions. Electrical transport measurements, coupled with microstructure studies and modeling, show that the ZT improvement is the result of low thermal conductivity caused by the increased phonon scattering by grain boundaries and defects. More importantly, ZT is about 1.2 at room temperature and 0.8 at 250°C, which makes these materials useful for cooling and power generation. Cooling devices that use these materials have produced high-temperature differences of 86°, 106°, and 119°C with hot-side temperatures set at 50°, 100°, and 150°C, respectively. This discovery sets the stage for use of a new nanocomposite approach in developing high-performance low-cost bulk thermoelectric materials.
4,695 citations
Journal Article•
4,230 citations
TL;DR: Nanocrystals (NCs) discussed in this Review are tiny crystals of metals, semiconductors, and magnetic material consisting of hundreds to a few thousand atoms each that are among the hottest research topics of the last decades.
Abstract: Nanocrystals (NCs) discussed in this Review are tiny crystals of metals, semiconductors, and magnetic material consisting of hundreds to a few thousand atoms each. Their size ranges from 2-3 to about 20 nm. What is special about this size regime that placed NCs among the hottest research topics of the last decades? The quantum mechanical coupling * To whom correspondence should be addressed. E-mail: dvtalapin@uchicago.edu. † The University of Chicago. ‡ Argonne National Lab. Chem. Rev. 2010, 110, 389–458 389
3,720 citations
TL;DR: It is shown that heat-carrying phonons with long mean free paths can be scattered by controlling and fine-tuning the mesoscale architecture of nanostructured thermoelectric materials, and an increase in ZT beyond the threshold of 2 highlights the role of, and need for, multiscale hierarchical architecture in controlling phonon scattering in bulk thermoeLECTrics.
Abstract: Controlling the structure of thermoelectric materials on all length scales (atomic, nanoscale and mesoscale) relevant for phonon scattering makes it possible to increase the dimensionless figure of merit to more than two, which could allow for the recovery of a significant fraction of waste heat with which to produce electricity.
3,670 citations
References
More filters
23,110 citations
TL;DR: A new mechanism for strong Anderson localization of photons in carefully prepared disordered dielectric superlattices with an everywhere real positive dielectrics constant is described.
Abstract: A new mechanism for strong Anderson localization of photons in carefully prepared disordered dielectric superlattices with an everywhere real positive dielectric constant is described. In three dimensions, two photon mobility edges separate high- and low-frequency extended states from an intermediate-frequency pseudogap of localized states arising from remnant geometric Bragg resonances. Experimentally observable consequences are discussed.
9,067 citations
"Thin-film thermoelectric devices wi..." refers background in this paper
..., similar to photon-localization in highly scattering medi...
[...]
14 Jul 1995
TL;DR: In this article, Rowe et al. proposed a method for reducing the thermal conductivity of a thermoelectric generator by reducing the carrier concentration of the generator, which was shown to improve the generator's performance.
Abstract: Introduction, D.M. Rowe General Principles and Theoretical Considerations Thermoelectric Phenomena, D.D. Pollock Coversion Efficiency and Figure-of-Merit, H.J. Goldsmid Thermoelectric Transport Theory, C.M. Bhandari Optimization of Carrier Concentration, C.M. Bhandari and D.M. Rowe Minimizing the Thermal Conductivity, C.M. Bhandari Selective Carrier Scattering in Thermoelectric Materials, Y.I. Ravich Thermomagnetic Phenomena, H.J. Goldsmid Material Preparation Preparation of Thermoelectric Materials from Melts, A. Borshchevsky Powder Metallurgy Techniques, A.N. Scoville PIES Method of Preparing Bismuth Alloys, T. Ohta and T. Kajikawa Preparation of Thermoelectric Materials by Mechanical Alloying, B.A. Cook, J.L. Harringa, and S.H. Han Preparation of Thermoelectric Films, K. Matsubara, T. Koyanagi, K. Nagao, and K. Kishimoto Measurement of Thermoelectric Properties Calculation of Peltier Device Performance, R.J. Buist Measurements of Electrical Properties, I.A. Nishida Measurement of Thermal Properties, R. Taylor Z-Meters, H.H. Woodbury, L.M. Levinson, and S. Lewandowski Methodology for Testing Thermoelectric Materials and Devices, R.J. Buist Thermoelectric Materials Bismuth Telluride, Antimony Telluride, and Their Solid Solutions, H. Scherrer and S. Scherrer Valence Band Structure and the Thermoelectric Figure-of-Merit of (Bi1-xSbx)Te3 Crystals, M. Stordeur Lead Telluride and Its Alloys, V. Fano Properties of the General Tags System, E.A. Skrabek and D.S. Trimmer Thermoelectric Properties of Silicides, C.B. Vining Polycrystalline Iron Disilicide as a Thermoelectric Generator Material, U. Birkholz, E. Gross, and U. Stohrer Thermoelectric Properties of Anisotropic MnSi1.75 , V.K. Zaitsev Low Carrier Mobility Materials for Thermoelectric Applications, V.K. Zaitsev, S.A. Ktitorov, and M.I. Federov Semimetals as Materials for Thermoelectric Generators, M.I. Fedorov and V.K. Zaitsev Silicon Germanium, C.B. Vining Rare Earth Compounds, B.J. Beaudry and K.A. Gschneidner, Jr. Thermoelectric Properties of High-Temperature Superconductors, M. Cassart and J.-P. Issi Boron Carbides, T.L. Aselage and D. Emin Thermoelectric Properties of Metallic Materials, A.T. Burkov and M.V. Vedernikov Neutron Irradiation Damage in SiGe Alloys, J.W. Vandersande New Materials and Performance Limits for Thermoelectric Cooling, G.A. Slack Thermoelectric Generation Miniature Semiconductor Thermoelectric Devices, D.M. Rowe Commercially Available Generators, A.G. McNaughton Modular RTG Technology, R.F. Hartman Peltier Devices as Generators, G. Min and D.M. Rowe Calculations of Generator Performance, M.H. Cobble Generator Applications Terrestrial Applications of Thermoelectric Generators, W.C. Hall Space Applications, G.L. Bennett SP-100 Space Subsystems, J.F. Mondt Safety Aspects of Thermoelectrics in Space, G.L. Bennett Low-Temperature Heat Conversion, K. Matsuura and D.M. Rowe Thermoelectric Refrigeration Introduction, H.J. Goldsmid Module Design and Fabrication, R. Marlow and E. Burke Cooling Thermoelements with Superconducting Leg, M.V. Vedernikov and V.L. Kuznetsov Applications of Thermoelectric Cooling Introduction, H.J. Goldsmid Commercial Peltier Modules, K.-I. Uemura Thermoelectrically Cooled Radiation Detectors, L.I. Anatychuk Reliability of Peltier Coolers in Fiber-Optic Laser Packages, R.M. Redstall and R. Studd Laboratory Equipment, K.-I. Uemura Large-Scale Cooling: Integrated Thermoelectric Element Technology, J.G. Stockholm Medium-Scale Cooling: Thermoelectric Module Technology, J.G. Stockholm Modeling of Thermoelectric Cooling Systems, J.G. Stockholm
4,192 citations
TL;DR: In this article, the authors proposed to use quantum-well superlattice structures to enhance the performance of thermoelectric coolers and showed that layering has the potential to increase significantly the figure of merit of a highly anisotropic material.
Abstract: Currently the materials with the highest thermoelectric figure of merit Z are ${\mathrm{Bi}}_{2}$${\mathrm{Te}}_{3}$ alloys. Therefore these compounds are the best thermoelectric refrigeration elements. However, since the 1960s only slow progress has been made in enhancing Z, either in ${\mathrm{Bi}}_{2}$${\mathrm{Te}}_{3}$ alloys or in other thermoelectric materials. So far, the materials used in applications have all been in bulk form. In this paper, it is proposed that it may be possible to increase Z of certain materials by preparing them in quantum-well superlattice structures. Calculations have been done to investigate the potential for such an approach, and also to evaluate the effect of anisotropy on the figure of merit. The calculations show that layering has the potential to increase significantly the figure of merit of a highly anisotropic material such as ${\mathrm{Bi}}_{2}$${\mathrm{Te}}_{3}$, provided that the superlattice multilayers are made in a particular orientation. This result opens the possibility of using quantum-well superlattice structures to enhance the performance of thermoelectric coolers.
3,202 citations
Additional excerpts
...One involves the use of quantum-confinement effect...
[...]
01 Jan 1987
2,842 citations