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nanostructured thermoelectric material

Tiva Sharifi, Xiang Zhang, Gelu Costin, Sadegh Yazdi, Cristiano F Woellner, Yang Liu, Chandra Sekhar Tiwary, Pulickel Ajayan
We show that thermoelectric materials can function as electrocatalysts and use thermoelectric voltage generated to initiate and boost electrocatalytic reactions. The electrocatalytic activity is promoted by the use of nanostructured thermoelectric materials in a hydrogen evolution reaction (HER) by the thermoelectricity generated from induced temperature gradients. This phenomenon is demonstrated using two-dimensional layered thermoelectric materials Sb2Te3 and Bi0.5Sb1.5Te3 where a current density approaching ∼50 mA/cm(2) is produced at zero potential for Bi0...
November 13, 2017: Nano Letters
Sarah Friedensen, Jerome T Mlack, Marija Drndić
Focused ion beam milling allows manipulation of the shape and size of nanostructures to create geometries potentially useful for opto-electronics, thermoelectrics, and quantum computing. We focus on using the ion beam to control the thickness of Bi2Se3 and to create nanowires from larger structures. Changes in the material structure of Bi2Se3 nanomaterials that have been milled using a focused ion beam are presented. In order to characterize the effects of ion beam processing on the samples, we use a variety of techniques including analytical transmission electron microscopy and atomic force microscopy...
October 18, 2017: Scientific Reports
Duc-The Ngo, Hung Thanh Le, Nong Van Ngo
We demonstrate an advanced approach using advanced in-situ transmission electron microscopy (TEM) to understand the interplay between nanostructures and thermoelectric (TE) properties of high-performance Mg-doped Zn4Sb3 TE system. With the technique, microstructure and crystal evolutions of TE material have been dynamically captured as a function of temperature from 300 K to 573 K. On heating, we have observed clearly precipitation and growth of a Zn-rich secondary phase as nanoinclusions in the matrix of primary Zn4Sb3 phase...
October 9, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
Takao Mori
Thermoelectrics (TE), the direct solid-state conversion of waste heat to electricity, is a promising field with potential wide-scale application for power generation. Intrinsic conflicts in the requirements for high electrical conductivity but (a) low thermal conductivity and (b) a large Seebeck coefficient have made enhancing TE performance difficult. Several recent striking advances in the field are reviewed. In regard to the former conflict, notable bottom-up nanostructuring methods for phonon-selective scattering are discovered, namely using nanosheets, dislocations, and most strikingly a process to fabricate nano-micropores leading to a 100% enhancement in the figure of merit (ZT ≈ 1...
September 29, 2017: Small
Giuseppe Sansone, Andrea Ferretti, Lorenzo Maschio
Within the semiclassical Boltzmann transport theory in the constant relaxation-time approximation, we perform an ab initio study of the transport properties of selected systems, including crystalline solids and nanostructures. A local (Gaussian) basis set is adopted and exploited to analytically evaluate band velocities as well as to access full and range-separated hybrid functionals (such as B3LYP, PBE0, or HSE06) at a moderate computational cost. As a consequence of the analytical derivative, our approach is computationally efficient and does not suffer from problems related to band crossings...
September 21, 2017: Journal of Chemical Physics
Wenyu Zhao, Zhiyuan Liu, Zhigang Sun, Qingjie Zhang, Ping Wei, Xin Mu, Hongyu Zhou, Cuncheng Li, Shifang Ma, Danqi He, Pengxia Ji, Wanting Zhu, Xiaolei Nie, Xianli Su, Xinfeng Tang, Baogen Shen, Xiaoli Dong, Jihui Yang, Yong Liu, Jing Shi
The ability to control chemical and physical structuring at the nanometre scale is important for developing high-performance thermoelectric materials. Progress in this area has been achieved mainly by enhancing phonon scattering and consequently decreasing the thermal conductivity of the lattice through the design of either interface structures at nanometre or mesoscopic length scales or multiscale hierarchical architectures. A nanostructuring approach that enables electron transport as well as phonon transport to be manipulated could potentially lead to further enhancements in thermoelectric performance...
September 13, 2017: Nature
Bo Fu, Guihua Tang, Yifei Li
Nanostructuring technology has been widely employed to reduce the thermal conductivity of thermoelectric materials because of the strong phonon-boundary scattering. Optimizing the carrier concentration can not only improve the electrical properties, but also affect the lattice thermal conductivity significantly due to the electron-phonon scattering. The lattice thermal conductivity of silicon nanostructures considering electron-phonon scattering is investigated for comparing the lattice thermal conductivity reductions resulting from nanostructuring technology and the carrier concentration optimization...
November 1, 2017: Physical Chemistry Chemical Physics: PCCP
Jian Zhang, Di Wu, Dongsheng He, Dan Feng, Meijie Yin, Xiaoying Qin, Jiaqing He
Lead telluride has long been realized as an ideal p-type thermoelectric material at an intermediate temperature range; however, its commercial applications are largely restricted by its n-type counterpart that exhibits relatively inferior thermoelectric performance. This major limitation is largely solved here, where it is reported that a record-high ZT value of ≈1.83 can be achieved at 773 K in n-type PbTe-4%InSb composites. This significant enhancement in thermoelectric performance is attributed to the incorporation of InSb into the PbTe matrix resulting in multiphase nanostructures that can simultaneously modulate the electrical and thermal transport...
August 21, 2017: Advanced Materials
Giselle A Elbaz, Wee-Liat Ong, Evan A Doud, Philip Kim, Daniel W Paley, Xavier Roy, Jonathan A Malen
Thermal management plays a critical role in the design of solid state materials for energy conversion. Lead halide perovskites have emerged as promising candidates for photovoltaic, thermoelectric, and optoelectronic applications, but their thermal properties are still poorly understood. Here, we report on the thermal conductivity, elastic modulus, and sound speed of a series of lead halide perovskites MAPbX3 (X = Cl, Br, I), CsPbBr3, and FAPbBr3 (MA = methylammonium, FA = formamidinium). Using frequency domain thermoreflectance, we find that the room temperature thermal conductivities of single crystal lead halide perovskites range from 0...
September 13, 2017: Nano Letters
Bin Liu, Jizhu Hu, Jun Zhou, Ronggui Yang
Thermoelectric materials which can convert energies directly between heat and electricity are used for solid state cooling and power generation. There is a big challenge to improve the efficiency of energy conversion which can be characterized by the figure of merit (ZT). In the past two decades, the introduction of nanostructures into bulk materials was believed to possibly enhance ZT. Nanocomposites is one kind of nanostructured material system which includes nanoconstituents in a matrix material or is a mixture of different nanoconstituents...
April 15, 2017: Materials
Guang Han, Ruizhi Zhang, Srinivas R Popuri, Heather F Greer, Michael J Reece, Jan-Willem G Bos, Wuzong Zhou, Andrew R Knox, Duncan H Gregory
A facile one-pot aqueous solution method has been developed for the fast and straightforward synthesis of SnTe nanoparticles in more than ten gram quantities per batch. The synthesis involves boiling an alkaline Na₂SnO₂ solution and a NaHTe solution for short time scales, in which the NaOH concentration and reaction duration play vital roles in controlling the phase purity and particle size, respectively. Spark plasma sintering of the SnTe nanoparticles produces nanostructured compacts that have a comparable thermoelectric performance to bulk counterparts synthesised by more time- and energy-intensive methods...
February 26, 2017: Materials
F Serrano-Sánchez, M Gharsallah, N M Nemes, N Biskup, M Varela, J L Martínez, M T Fernández-Díaz, J A Alonso
Sb-doped Bi2Te3 is known since the 1950s as the best thermoelectric material for near-room temperature operation. Improvements in material performance are expected from nanostructuring procedures. We present a straightforward and fast method to synthesize already nanostructured pellets that show an enhanced ZT due to a remarkably low thermal conductivity and unusually high Seebeck coefficient for a nominal composition optimized for arc-melting: Bi0.35Sb1.65Te3. We provide a detailed structural analysis of the Bi2-xSbxTe3 series (0 ≤ x ≤ 2) based on neutron powder diffraction as a function of composition and temperature that reveals the important role played by atomic vibrations...
July 24, 2017: Scientific Reports
Ki Sung Kim, Young-Min Kim, Hyeona Mun, Jisoo Kim, Jucheol Park, Albina Y Borisevich, Kyu Hyoung Lee, Sung Wng Kim
Structural defects often dominate the electronic- and thermal-transport properties of thermoelectric (TE) materials and are thus a central ingredient for improving their performance. However, understanding the relationship between TE performance and the disordered atomic defects that are generally inherent in nanostructured alloys remains a challenge. Herein, the use of scanning transmission electron microscopy to visualize atomic defects directly is described and disordered atomic-scale defects are demonstrated to be responsible for the enhancement of TE performance in nanostructured Ti1-x Hfx NiSn1-y Sby half-Heusler alloys...
July 24, 2017: Advanced Materials
Kaleem Ahmad, Chunlei Wan
The advancement in nanostructured powder processing has attracted great interest as a cost effective and scalable strategy for high performance thermoelectric bulk materials. However, the level of technical breakthrough realized in quantum dot supperlattices/wires has not yet been demonstrated in these materials. Here, we report the first ever study on the uniform dispersion of single wall carbon nanotubes (SWCNTs) in nanostructured Bi2Te3 bulk, and their effect on thermoelectric parameters above room temperature...
July 20, 2017: Nanotechnology
Biplab Paul, Jun Lu, Per Eklund
Because of their inherent rigidity and brittleness, inorganic materials have seen limited use in flexible thermoelectric applications. On the other hand, for high output power density and stability, the use of inorganic materials is required. Here, we demonstrate a concept of fully inorganic flexible thermoelectric thin films with Ca3Co4O9-on-mica. Ca3Co4O9 is promising not only because of its high Seebeck coefficient and good electrical conductivity but also because of the abundance, low cost, and nontoxicity of its constituent raw materials...
August 2, 2017: ACS Applied Materials & Interfaces
Yanguang Zhou, Xiaojing Gong, Ben Xu, Ming Hu
Thermoelectric (TE) materials manifest themselves to enable direct conversion of temperature differences to electric power and vice versa. Though remarkable advances have been achieved in the past decades for various TE systems, the energy conversion efficiency of TE devices, which is characterized by a dimensionless figure-of-merit (ZT = S(2)σT/(κel + κph)), generally remains a poor factor that severely limits TE devices' competitiveness and range of employment. The bottleneck for substantially boosting the ZT coefficient lies in the strong interdependence of the physical parameters involved in electronic (S and σ, and κel) and phononic (κph) transport...
July 20, 2017: Nanoscale
Pavlo Zolotavin, Charlotte I Evans, Douglas Natelson
Nanoscale structuring holds promise to improve the thermoelectric properties of materials for energy conversion and photodetection. We report a study of the spatial distribution of the photothermoelectric voltage in thin-film nanowire devices fabricated from a single metal. A focused laser beam is used to locally heat the metal nanostructure via a combination of direct absorption and excitation of a plasmon resonance in Au devices. As seen previously, in nanowires shorter than the spot size of the laser, we observe a thermoelectric voltage distribution that is consistent with the local Seebeck coefficient being spatially dependent on the width of the nanostructure...
July 6, 2017: Nanoscale
Hamid Emadi, Masoud Salavati-Niasari, Azam Sobhani
The design of nanostructures with favored shape, particle size and structure is one of the most important fields of nanoscience. To reach this target hydrothermal method is one of the most applicable methods which allow us to obtain favored structures by changing some parameters. This review focuses on synthesis of some transition metal sulfides by hydrothermal method because of technological importance of this group of material. The common sulfides of Mn, Co, Ni, Cu, Zn, Ag and Cd are introduced and a mechanism proposed for their synthesis...
June 16, 2017: Advances in Colloid and Interface Science
Azhar Ali, Yixi Chen, Venkata Vasiraju, Sreeram Vaddiraju
Research on thermoelectrics has seen a huge resurgence since the early 1990s. The ability of tuning a material's electrical and thermal transport behavior upon nanostructuring has led to this revival. Nevertheless, thermoelectric performances of nanowires and related materials lag far behind those achieved with thin-film superlattices and quantum dot-based materials. This is despite the fact that nanowires offer many distinct advantages in enhancing the thermoelectric performances of materials. The simplicity of the strategy is the first and foremost advantage...
June 19, 2017: Nanotechnology
Manisha Samanta, Kanishka Biswas
GeTe and its derivatives constituting Pb-free elements have been well known as potential thermoelectric materials for the last five decades, which offer paramount technological importance. The main constraint in the way of optimizing thermoelectric performance of GeTe is the high lattice thermal conductivity (κlat). Herein, we demonstrate low κlat (∼0.7 W/m·K) and a significantly high thermoelectric figure of merit (ZT = 2.1 at 630 K) in the Sb-doped pseudoternary (GeTe)1-2x(GeSe)x(GeS)x system by two-step strategies...
June 28, 2017: Journal of the American Chemical Society
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