The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Sergey V Ovsyannikov - One of the best experts on this subject based on the ideXlab platform.
-
enhanced power factor and high pressure effects in bi sb 2 te se 3 Thermoelectrics
Applied Physics Letters, 2015Co-Authors: Sergey V Ovsyannikov, Natalia V Morozova, Igor V Korobeinikov, Lidia N Lukyanova, Andrey Yu Manakov, Anna Y Likhacheva, A I Ancharov, Alexander P VokhmyaninAbstract:We investigated the effects of applied high pressure on thermoelectric, electric, structural, and optical properties of single-crystalline Thermoelectrics, Bi2Te3, BixSb2−xTe3 (x = 0.4, 0.5, 0.6), and Bi2Te2.73Se0.27 with the high thermoelectric performance. We established that moderate pressure of about 2–4 GPa can greatly enhance the thermoelectric power factor of all of them. X-ray diffraction and Raman studies on Bi2Te3 and Bi0.5Sb1.5Te3 found anomalies at similar pressures, indicating a link between crystal structure deformation and physical properties. We speculate about possible mechanisms of the power factor enhancement and suppose that pressure/stress tuning can be an effective tool for the optimization of the thermoelectric performance.
-
High-Pressure Routes in the Thermoelectricity or How One Can Improve a Performance of Thermoelectrics†
Chemistry of Materials, 2010Co-Authors: Sergey V Ovsyannikov, Vladimir V. ShchennikovAbstract:High pressure has a strong impact on materials. In regards to Thermoelectrics, pressure is able to significantly improve their thermoelectric (TE) performance (i.e., power factor and figure of merit), and for this reason, pressure is a powerful tool for energy conversion technologies. This paper reviews studies on thermoelectric properties of relevant materials (PbTe, PbSe, Bi2Te3, Sb2Te3, and others) under pressure. It is figured out that enhanced thermoelectric properties of lead telluride and bismuth telluride appear beyond a range of energy gaps proposed for a “conventional” thermoelectricity in narrow-gap semiconductors. An example given for SmTe hints that pressure effects on the thermoelectric performance may be tremendous. This review also attends studies on high-pressure thermoelectric properties in the presence of a nonzero magnetic field. Influence of magnetic-field-related effects, such as magnetoresistance, magnetothermopower (Nernst−Ettingshausen effects), and Maggi−Reghi−Leduc effect is ana...
Jeffrey G Snyder - One of the best experts on this subject based on the ideXlab platform.
-
low symmetry rhombohedral gete Thermoelectrics
Joule, 2018Co-Authors: Xinyue Zhang, Lidong Chen, Anubhav Jain, Zhiwei Chen, Siqi Lin, Jiahong Shen, Ian T Witting, Alireza Faghaninia, Yue Chen, Jeffrey G SnyderAbstract:Summary High-symmetry thermoelectric materials usually have the advantage of very high band degeneracy, while low-symmetry Thermoelectrics have the advantage of very low lattice thermal conductivity. If the symmetry breaking of band degeneracy is small, both effects may be realized simultaneously. Here we demonstrate this principle in rhombohedral GeTe alloys, having a slightly reduced symmetry from its cubic structure, to realize a record figure of merit ( zT ∼ 2.4) at 600 K. This is enabled by the control of rhombohedral distortion in crystal structure for engineering the split low-symmetry bands to be converged and the resultant compositional complexity for simultaneously reducing the lattice thermal conductivity. Device ZT as high as 1.3 in the rhombohedral phase and 1.5 over the entire working temperature range of GeTe alloys make this material the most efficient thermoelectric to date. This work paves the way for exploring low-symmetry materials as efficient Thermoelectrics.
-
vacancy induced dislocations within grains for high performance pbse Thermoelectrics
Nature Communications, 2017Co-Authors: Zhiwei Chen, Jeffrey G Snyder, Siqi Lin, Jiawen Shen, Yunjie Chang, Riley Hanus, Yanzhong PeiAbstract:To minimize the lattice thermal conductivity in Thermoelectrics, strategies typically focus on the scattering of low-frequency phonons by interfaces and high-frequency phonons by point defects. In addition, scattering of mid-frequency phonons by dense dislocations, localized at the grain boundaries, has been shown to reduce the lattice thermal conductivity and improve the thermoelectric performance. Here we propose a vacancy engineering strategy to create dense dislocations in the grains. In Pb1-xSb2x/3Se solid solutions, cation vacancies are intentionally introduced, where after thermal annealing the vacancies can annihilate through a number of mechanisms creating the desired dislocations homogeneously distributed within the grains. This leads to a lattice thermal conductivity as low as 0.4 Wm-1 K-1 and a high thermoelectric figure of merit, which can be explained by a dislocation scattering model. The vacancy engineering strategy used here should be equally applicable for solid solution Thermoelectrics and provides a strategy for improving zT.
-
low effective mass leading to high thermoelectric performance
Energy and Environmental Science, 2012Co-Authors: Aaron D. Lalonde, Heng Wang, Jeffrey G SnyderAbstract:High Seebeck coefficient by creating large density-of-states effective mass through either electronic structure modification or manipulating nanostructures is commonly considered as a route to advanced Thermoelectrics. However, large density-of-state due to flat bands leads to large transport effective mass, which results in a simultaneous decrease of mobility. In fact, the net effect of such a high effective mass is a lower thermoelectric figure of merit, zT, when the carriers are predominantly scattered by phonons according to the deformation potential theory of Bardeen–Shockley. We demonstrate that the beneficial effect of light effective mass contributes to high zT in n-type thermoelectric PbTe, where doping and temperature can be used to tune the effective mass. This clear demonstration of the deformation potential theory to Thermoelectrics shows that the guiding principle for band structure engineering should be low effective mass along the transport direction.
-
low effective mass leading to high thermoelectric performance
arXiv: Materials Science, 2011Co-Authors: Aaron D. Lalonde, Heng Wang, Jeffrey G SnyderAbstract:High Seebeck coefficient by creating large density of state (DOS) around the Fermi level through either electronic structure modification or manipulating nanostructures, is commonly considered as a route to advanced Thermoelectrics. However, large density of state due to flat bands leads to large effective mass, which results in a simultaneous decrease of mobility. In fact, the net effect of high effective mass is a lower thermoelectric figure of merit when the carriers are predominantly scattered by acoustic phonons according to the deformation potential theory of Bardeen-Shockley. We demonstrate the beneficial effect of light effective mass leading to high power factor in n-type thermoelectric PbTe, where doping and temperature can be used to tune the effective mass. This clear demonstration of the deformation potential theory to Thermoelectrics shows that the guiding principle for band structure engineering should be low effective mass along the transport direction.
-
lead telluride alloy Thermoelectrics
Materials Today, 2011Co-Authors: Aaron D. Lalonde, Heng Wang, Yanzhong Pei, Jeffrey G SnyderAbstract:The opportunity to use solid-state Thermoelectrics for waste heat recovery has reinvigorated the field of Thermoelectrics in tackling the challenges of energy sustainability. While thermoelectric generators have decades of proven reliability in space, from the 1960s to the present, terrestrial uses have so far been limited to niche applications on Earth because of a relatively low material efficiency. Lead telluride alloys were some of the first materials investigated and commercialized for generators but their full potential for Thermoelectrics has only recently been revealed to be far greater than commonly believed. By reviewing some of the past and present successes of PbTe as a thermoelectric material we identify the issues for achieving maximum performance and successful band structure engineering strategies for further improvements that can be applied to other thermoelectric materials systems.
David L Carroll - One of the best experts on this subject based on the ideXlab platform.
-
layered bi2se3 nanoplate polyvinylidene fluoride composite based n type thermoelectric fabrics
ACS Applied Materials & Interfaces, 2015Co-Authors: Chaochao Dun, Corey A Hewitt, Huihui Huang, David S Montgomery, Wanyi Nie, Qike Jiang, David L CarrollAbstract:In this study, we report the fabrication of n-type flexible thermoelectric fabrics using layered Bi2Se3 nanoplate/polyvinylidene fluoride (PVDF) composites as the thermoelectric material. These composites exhibit room temperature Seebeck coefficient and electrical conductivity values of -80 μV K(-1) and 5100 S m(-1), respectively, resulting in a power factor approaching 30 μW m(-1)K(-2). The temperature-dependent thermoelectric properties reveal that the composites exhibit metallic-like electrical conductivity, whereas the thermoelectric power is characterized by a heterogeneous model. These composites have the potential to be used in atypical applications for Thermoelectrics, where lightweight and flexible materials would be beneficial. Indeed, bending tests revealed excellent durability of the thermoelectric fabrics. We anticipate that this work may guide the way for fabricating high performance thermoelectric fabrics based on layered V-VI nanoplates.
-
multilayered carbon nanotube polymer composite based thermoelectric fabrics
Nano Letters, 2012Co-Authors: Corey A Hewitt, A B Kaiser, Siegmar Roth, Matt Craps, R Czerw, David L CarrollAbstract:Thermoelectrics are materials capable of the solid-state conversion between thermal and electrical energy. Carbon nanotube/polymer composite thin films are known to exhibit thermoelectric effects, however, have a low figure of merit (ZT) of 0.02. In this work, we demonstrate individual composite films of multiwalled carbon nanotubes (MWNT)/polyvinylidene fluoride (PVDF) that are layered into multiple element modules that resemble a felt fabric. The thermoelectric voltage generated by these fabrics is the sum of contributions from each layer, resulting in increased power output. Since these fabrics have the potential to be cheaper, lighter, and more easily processed than the commonly used thermoelectric bismuth telluride, the overall performance of the fabric shows promise as a realistic alternative in a number of applications such as portable lightweight electronics.
Brian Skinner - One of the best experts on this subject based on the ideXlab platform.
-
quantized thermoelectric hall effect induces giant power factor in a topological semimetal
Nature Communications, 2020Co-Authors: Fei Han, Nina Andrejevic, Thanh D Nguyen, Vladyslav Kozii, Quynh Nguyen, Tom Hogan, Zhiwei Ding, Ricardo Pablopedro, Shreya Parjan, Brian SkinnerAbstract:Thermoelectrics are promising by directly generating electricity from waste heat. However, (sub-)room-temperature Thermoelectrics have been a long-standing challenge due to vanishing electronic entropy at low temperatures. Topological materials offer a new avenue for energy harvesting applications. Recent theories predicted that topological semimetals at the quantum limit can lead to a large, non-saturating thermopower and a quantized thermoelectric Hall conductivity approaching a universal value. Here, we experimentally demonstrate the non-saturating thermopower and quantized thermoelectric Hall effect in the topological Weyl semimetal (WSM) tantalum phosphide (TaP). An ultrahigh longitudinal thermopower [Formula: see text] and giant power factor [Formula: see text] are observed at ~40 K, which is largely attributed to the quantized thermoelectric Hall effect. Our work highlights the unique quantized thermoelectric Hall effect realized in a WSM toward low-temperature energy harvesting applications.
-
quantized thermoelectric hall effect induces giant power factor in a topological semimetal
arXiv: Mesoscale and Nanoscale Physics, 2019Co-Authors: Fei Han, Nina Andrejevic, Thanh D Nguyen, Vladyslav Kozii, Quynh Nguyen, Tom Hogan, Zhiwei Ding, Ricardo Pablopedro, Shreya Parjan, Brian SkinnerAbstract:Thermoelectrics are promising by directly generating electricity from waste heat. However, (sub-)room-temperature Thermoelectrics have been a long-standing challenge due to vanishing electronic entropy at low temperatures. Topological materials offer a new avenue for energy harvesting applications. Recent theories predicted that topological semimetals at the quantum limit can lead to a large, non-saturating thermopower and a quantized thermoelectric Hall conductivity approaching a universal value. Here, we experimentally demonstrate the non-saturating thermopower and quantized thermoelectric Hall effect in the topological Weyl semimetal (WSM) tantalum phosphide (TaP). An ultrahigh longitudinal thermopower Sxx= 1.1x10^3 muV/K and giant power factor ~525 muW/cm/K^2 are observed at ~40K, which is largely attributed to the quantized thermoelectric Hall effect. Our work highlights the unique quantized thermoelectric Hall effect realized in a WSM toward low-temperature energy harvesting applications.
Chen Zhi-gang - One of the best experts on this subject based on the ideXlab platform.
-
Rational structure design and manipulation advance SnSe Thermoelectrics
'Royal Society of Chemistry (RSC)', 2020Co-Authors: Shi Xiao-lei, Chen Wen-yi, Tao Xinyong, Zou Jin, Chen Zhi-gangAbstract:Thermoelectrics can directly harvest electricity from waste heat through the Seebeck effect, therefore it has been regarded as an eco-friendly and sustainable solution to alleviate the pressure from fossil fuel consumption and environmental pollution. Rational structural manipulation is critical to improving the thermoelectric performance of materials, and a timely review is required to summarize the recent progress on the novel structural design for Thermoelectrics. In this review, taking SnSe as a typical example and combined with other thermoelectric materials, we summarize recent advances in the rational structural manipulation for thermoelectric materials, including point defects, dislocations, boundaries, nanoinclusions, and nanopores. The inherent links between syntheses, characterizations, and thermoelectric properties by tailoring the structures are established. In addition, we discuss the development of nanoscale thermoelectric materials and their potential for applying to flexible thermoelectric devices. This review can guide the design of high-performance thermoelectric materials
-
SrTiO3-based Thermoelectrics: Progress and challenges
'Elsevier BV', 2020Co-Authors: Shi Xiao-lei, Dargusch Matthew, Wu Hao, Liu Qingfeng, Zhou Wei, Lu Siyu, Shao Zongping, Chen Zhi-gangAbstract:Thermoelectrics, enabling the direct energy conversion between electricity and heat, provide alternatives for conventional power generation and refrigeration with considerable efficiency. As one of the most promising oxide thermoelectric candidates, SrTiO3 shows an intrinsically high Seebeck coefficient and high stability at high temperatures. This review aims to summarize the progress of SrTiO3-based Thermoelectrics from crystal and band structures to the strategies for tuning electrical and phonon transport. The article also highlights recent advances in the field of two-dimensional electronic gas system in SrTiO3 and suggests potential methods for further improving their thermoelectric performance. This review fills the gap of an overview of the progress and challenges associated with the development of SrTiO3-based Thermoelectrics and paves a way to design high-performance oxide-based thermoelectric materials and devices
-
High-performance GeTe-Based Thermoelectrics: from materials to devices
'Wiley', 2020Co-Authors: Liu Wei-di, Liu Qingfeng, Zhou Wei, Shao Zongping, Wang De-zhuang, Chen Zhi-gangAbstract:High-performance GeTe-based Thermoelectrics have been recently attracting growing research interest. Here, an overview is presented of the structural and electronic band characteristics of GeTe. Intrinsically, compared to low-temperature rhombohedral GeTe, the high-symmetry and high-temperature cubic GeTe has a low energy offset between L and sigma points of the valence band, the reduced direct bandgap and phonon group velocity, and as a result, high thermoelectric performance. Moreover, their thermoelectric performance can be effectively enhanced through either carrier concentration optimization, band structure engineering (bandgap reduction, band degeneracy, and resonant state engineering), or restrained lattice thermal conductivity (phonon velocity reduction or phonon scattering). Consequently, the dimensionless figure of merit, ZT values, of GeTe-based thermoelectric materials can be higher than 2. The mechanical and thermal stabilities of GeTe-based Thermoelectrics are highlighted, and it is found that they are suitable for practical thermoelectric applications except for their high cost. Finally, it is recognized that the performance of GeTe-based materials can be further enhanced through synergistic effects. Additionally, proper material selection and module design can further boost the energy conversion efficiency of GeTe-based Thermoelectrics
-
Fiber-based Thermoelectrics for solid, portable, and wearable electronics
'Royal Society of Chemistry (RSC)', 2020Co-Authors: Shi Xiao-lei, Chen Wen-yi, Zou Jin, Zhang Ting, Chen Zhi-gangAbstract:With the growing demand for solid, portable, and wearable electronics, exploring recyclable and stable charging and cooling techniques is of significance. Fiber-based Thermoelectrics, enabling sustainable power generation driven by the temperature difference or refrigeration without noise and freon, exhibit great potentials for applying in advanced electronics. In this work, we review significant advances in fiber-based Thermoelectrics, including inorganic fibers, organic fibers, inorganic/organic hybrid fibers, and fiber-based fabrics and devices. Fundamentals, synthesis, characterizations, property evaluation, and applications of thermoelectric fibers are comprehensively discussed with carefully selected cases, and corresponding thermoelectric devices based on these advanced fibers are introduced for both power generation and refrigeration. Further, we point out the challenges and future directions toward developments of fiber-based Thermoelectrics
-
Advanced thermoelectric design: from materials and structures to devices
'American Chemical Society (ACS)', 2020Co-Authors: Shi Xiao-lei, Zou Jin, Chen Zhi-gangAbstract:The long-standing popularity of thermoelectric materials has contributed to the creation of various thermoelectric devices and stimulated the development of strategies to improve their thermoelectric performance. In this review, we aim to comprehensively summarize the state-of-the-art strategies for the realization of high-performance thermoelectric materials and devices by establishing the links between synthesis, structural characteristics, properties, underlying chemistry and physics, including structural design (point defects, dislocations, interfaces, inclusions, and pores), multidimensional design (quantum dots/wires, nanoparticles, nanowires, nano- or microbelts, few-layered nanosheets, nano- or microplates, thin films, single crystals, and polycrystalline bulks), and advanced device design (thermoelectric modules, miniature generators and coolers, and flexible thermoelectric generators). The outline of each strategy starts with a concise presentation of their fundamentals and carefully selected examples. In the end, we point out the controversies, challenges, and outlooks toward the future development of thermoelectric materials and devices. Overall, this review will serve to help materials scientists, chemists, and physicists, particularly students and young researchers, in selecting suitable strategies for the improvement of Thermoelectrics and potentially other relevant energy conversion technologies
