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nanostructured thermoelectric material

Manisha Samanta, Subhajit Roychowdhury, Jay Ghatak, Suresh Perumal, Kanishka Biswas
Waste heat sources are generally diffused and provide a range of temperatures rather than a particular temperature. Thus, thermoelectric waste heat to electricity conversion requires high average thermoelectric figure of merit (ZTavg) of materials over the entire working temperature along with high peak thermoelectric figure of merit (ZTmax). Herein, we report an ultrahigh ZTavg of 1.4 for (GeTe)80(AgSbSe2)20 [TAGSSe-80] in the temperature range of 300-700K, which is one of the highest value measured among the state-of-art Pb-free thermoelectric materials...
April 24, 2017: Chemistry: a European Journal
Yan Jin, Yingling Tan, Xiaozhen Hu, Bin Zhu, Qinghui Zheng, Zijiao Zhang, Guoying Zhu, Qian Yu, Zhong Jin, Jia Zhu
Alloy anodes possessed of high theoretical capacity show great potential for next-generation advanced lithium-ion battery. Even though huge volume change during lithium insertion and extraction leads to severe problems, such as pulverization and an unstable solid-electrolyte interphase (SEI), various nanostructures including nanoparticles, nanowires, and porous networks can address related challenges to improve electrochemical performance. However, the complex and expensive fabrication process hinders the widespread application of nanostructured alloy anodes, which generate an urgent demand of low-cost and scalable processes to fabricate building blocks with fine controls of size, morphology, and porosity...
April 25, 2017: ACS Applied Materials & Interfaces
Zhiwei Chen, Zhengzhong Jian, Wen Li, Yunjie Chang, Binghui Ge, Riley Hanus, Jiong Yang, Yue Chen, Mingxin Huang, Gerald Jeffrey Snyder, Yanzhong Pei
Phonon scattering by nanostructures and point defects has become the primary strategy for minimizing the lattice thermal conductivity (κL ) in thermoelectric materials. However, these scatterers are only effective at the extremes of the phonon spectrum. Recently, it has been demonstrated that dislocations are effective at scattering the remaining mid-frequency phonons as well. In this work, by varying the concentration of Na in Pb0.97 Eu0.03 Te, it has been determined that the dominant microstructural features are point defects, lattice dislocations, and nanostructure interfaces...
April 11, 2017: Advanced Materials
No-Won Park, Jay-Young Ahn, Tae-Hyun Park, Jung-Hun Lee, Won-Yong Lee, Kwanghee Cho, Young-Gui Yoon, Chel-Jong Choi, Jin-Seong Park, Sang-Kwon Lee
Recently, significant progress has been made in increasing the figure-of-merit (ZT) of various nanostructured materials, including thin-film and quantum dot superlattice structures. Studies have focused on the size reduction and control of the surface or interface of nanostructured materials since these approaches enhance the thermopower and phonon scattering in quantum and superlattice structures. Currently, bismuth-tellurium-based semiconductor materials are widely employed for thermoelectric (TE) devices such as TE energy generators and coolers, in addition to other sensors, for use at temperatures under 400 K...
April 3, 2017: Nanoscale
Giuseppe Romano, Alexie M Kolpak
Boundary-engineering in nanostructures has the potential to dramatically impact the development of materials for high- efficiency conversion of thermal energy directly into electricity. In particular, nanostructuring of semiconductors can lead to strong suppression of heat transport with little degradation of electrical conductivity. Although this combination of material properties is promising for thermoelectric materials, it remains largely unexplored. In this work, we introduce a novel concept, the directional phonon suppression function, to unravel boundary-dominated heat transport in unprecedented detail...
March 24, 2017: Scientific Reports
Maureen J Lagos, Andreas Trügler, Ulrich Hohenester, Philip E Batson
Imaging of vibrational excitations in and near nanostructures is essential for developing low-loss infrared nanophotonics, controlling heat transport in thermal nanodevices, inventing new thermoelectric materials and understanding nanoscale energy transport. Spatially resolved electron energy loss spectroscopy has previously been used to image plasmonic behaviour in nanostructures in an electron microscope, but hitherto it has not been possible to map vibrational modes directly in a single nanostructure, limiting our understanding of phonon coupling with photons and plasmons...
March 22, 2017: Nature
Xiaolong Xu, Qingjun Song, Haifeng Wang, Pan Li, Kun Zhang, Yilun Wang, Kai Yuan, Zichen Yang, Yu Ye, Lun Dai
The group IV-VI compound tin selenide (SnSe) has recently attracted particular interest due to its unexpectedly low thermal conductivity and high power factor and shows great promise for thermoelectric applications. With an orthorhombic lattice structure, SnSe displays intriguing anisotropic properties due to the low symmetry of the puckered in-plane lattice structure. When thermoelectric materials, such as SnSe, have decreased dimensionality, their thermoelectric conversion efficiency may be improved due to increased power factor and decreased thermal conductivity...
March 28, 2017: ACS Applied Materials & Interfaces
Zi-Zhen Lin, Cong-Liang Huang, Wen-Kai Zhen, Yan-Hui Feng, Xin-Xin Zhang, Ge Wang
The hot-wire method is applied in this paper to probe the thermal conductivity (TC) of Cu and Ni nanoparticle packed beds (NPBs). A different decrease tendency of TC versus porosity than that currently known is discovered. The relationship between the porosity and nanostructure is investigated to explain this unusual phenomenon. It is found that the porosity dominates the TC of the NPB in large porosities, while the TC depends on the contact area between nanoparticles in small porosities. Meanwhile, the Vickers hardness (HV) of NPBs is also measured...
December 2017: Nanoscale Research Letters
Lina Yang, Austin J Minnich
Nanocrystalline thermoelectric materials based on Si have long been of interest because Si is earth-abundant, inexpensive, and non-toxic. However, a poor understanding of phonon grain boundary scattering and its effect on thermal conductivity has impeded efforts to improve the thermoelectric figure of merit. Here, we report an ab-initio based computational study of thermal transport in nanocrystalline Si-based materials using a variance-reduced Monte Carlo method with the full phonon dispersion and intrinsic lifetimes from first-principles as input...
March 14, 2017: Scientific Reports
Tiejun Zhu, Yintu Liu, Chenguang Fu, Joseph P Heremans, Jeffrey G Snyder, Xinbing Zhao
The past two decades have witnessed the rapid growth of thermoelectric (TE) research. Novel concepts and paradigms are described here that have emerged, targeting superior TE materials and higher TE performance. These superior aspects include band convergence, "phonon-glass electron-crystal", multiscale phonon scattering, resonant states, anharmonicity, etc. Based on these concepts, some new TE materials with distinct features have been identified, including solids with high band degeneracy, with cages in which atoms rattle, with nanostructures at various length scales, etc...
March 6, 2017: Advanced Materials
Mouna Gharsallah, Federico Serrano-Sanchez, Norbert M Nemes, Jose Luis Martinez, Jose Antonio Alonso
In competitive thermoelectric devices for energy conversion and generation, high-efficiency materials of both n-type and p-type are required. For this, Bi2Te3-based alloys have the best thermoelectric properties in room temperature applications. Partial replacement of tellurium by selenium is expected to introduce new donor states in the band gap, which would alter electrical conductivity and thermopower. We report on the preparation of n-type Bi2(Te1-xSex)3 solid solutions by a straightforward arc-melting technique, yielding nanostructured polycrystalline pellets...
December 2017: Nanoscale Research Letters
Biao Xu, Tianli Feng, Matthias T Agne, Lin Zhou, Xiulin Ruan, G Jeffery Snyder, Yue Wu
To enhance the performance of thermoelectric materials and enable access to their widespread applications, it is beneficial yet challenging to synthesize hollow nanostructures in large quantities, with high porosity, low thermal conductivity (κ) and excellent figure of merit (z T). Herein we report a scalable (ca. 11.0 g per batch) and low-temperature colloidal processing route for Bi2 Te2.5 Se0.5 hollow nanostructures. They are sintered into porous, bulk nanocomposites (phi 10 mm×h 10 mm) with low κ (0...
January 12, 2017: Angewandte Chemie
Soudabeh Mashhadi, Dinh Loc Duong, Marko Burghard, Klaus Kern
Tuning the electron and phonon transport properties of thermoelectric materials by nanostructuring has enabled improving their thermopower figure of merit. Three-dimensional topological insulators, including many bismuth chalcogenides, attract increasing attention for this purpose, as their topologically protected surface states are promising to further enhance the thermoelectric performance. While individual bismuth chalcogenide nanostructures have been studied with respect to their photothermoelectric properties, nanostructured p-n junctions of these compounds have not yet been explored...
January 11, 2017: Nano Letters
Shuankui Li, Tianju Fan, Xuerui Liu, Fusheng Liu, Hong Meng, Yidong Liu, Feng Pan
Novel Bi2Te3/graphene quantum dots (Bi2Te3/GQDs) hybrid nanosheets with a unique structure that GQDs are homogeneously embedded in the Bi2Te3 nanosheet matrix have been synthesized by a simple solution-based synthesis strategy. A significantly reduced thermal conductivity and enhanced powder factor are observed in the Bi2Te3/GQDs hybrid nanosheets, which is ascribed to the optimized thermoelectric transport properties of the Bi2Te3/GQDs interface. Furthermore, by varying the size of the GQDs, the thermoelectric performance of Bi2Te3/GQDs hybrid nanostructures could be further enhanced, which could be attributed to the optimization of the density and dispersion manner of the GQDs in the Bi2Te3 matrix...
February 1, 2017: ACS Applied Materials & Interfaces
Taehan Yeo, Hayoung Hwang, Dongjoon Shin, Byungseok Seo, Wonjoon Choi
There is an urgent need to develop a suitable energy source owing to the rapid development of various innovative devices using micro-nanotechnology. The thermopower wave (TW), which produces a high specific power during the combustion of solid fuel inside micro-nanostructure materials, is a unique energy source for unusual platforms that cannot use conventional energy sources. Here, we report on the significant enhancement of hybrid energy generation of pyroelectrics and thermoelectrics from TWs in carbon nanotube (CNT)-PZT (lead zirconate titanate, P(Z0...
January 4, 2017: Nanotechnology
S Aminorroaya Yamini, D R G Mitchell, M Avdeev
Multiphase thermoelectric materials have recently attracted considerable attention due to the high thermoelectric efficiencies which can be achieved in these compounds compared to their single-phase counterparts. However, there is very little known on the structural evolution of these phases as a function of temperature. In this work we performed an in situ high temperature structural characterisation of recently reported high efficiency p-type multiphase (PbTe)0.65(PbS)0.25(PbSe)0.1 compounds by hot stage transmission electron microscopy and high-resolution neutron powder diffraction...
December 7, 2016: Physical Chemistry Chemical Physics: PCCP
Dongwook Lee, Sayed Youssef Sayed, Sangyeop Lee, Chris Adam Kuryak, Jiawei Zhou, Gang Chen, Yang Shao-Horn
Poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) has high electrical conductivity (∼10(3) S cm(-1)) but it exhibits a low Seebeck coefficient (<15 μV K(-1)), resulting in a low power factor. Mixing PEDOT:PSS with nanostructured semiconductors can enhance the Seebeck coefficient and achieve an improved thermoelectric power factor. However, underlying mechanisms for those composite thermoelectric systems are scarcely understood so far. In this study, quantitative analyses on the electrical conductivity and Seebeck coefficient for the heterostructures of nanometer-thick PEDOT:PSS on single-crystal Si (001) on sapphire (SOS) are reported...
December 1, 2016: Nanoscale
Fariborz Kargar, Bishwajit Debnath, Joona-Pekko Kakko, Antti Säynätjoki, Harri Lipsanen, Denis L Nika, Roger K Lake, Alexander A Balandin
Similar to electron waves, the phonon states in semiconductors can undergo changes induced by external boundaries. However, despite strong scientific and practical importance, conclusive experimental evidence of confined acoustic phonon polarization branches in individual free-standing nanostructures is lacking. Here we report results of Brillouin-Mandelstam light scattering spectroscopy, which reveal multiple (up to ten) confined acoustic phonon polarization branches in GaAs nanowires with a diameter as large as 128 nm, at a length scale that exceeds the grey phonon mean-free path in this material by almost an order-of-magnitude...
November 10, 2016: Nature Communications
Kunsu Park, Kyunghan Ahn, Joonil Cha, Sanghwa Lee, Sue In Chae, Sung-Pyo Cho, Siheon Ryee, Jino Im, Jaeki Lee, Su-Dong Park, Myung Joon Han, In Chung, Taeghwan Hyeon
Thermoelectrics directly converts waste heat into electricity and is considered a promising means of sustainable energy generation. While most of the recent advances in the enhancement of the thermoelectric figure of merit (ZT) resulted from a decrease in lattice thermal conductivity by nanostructuring, there have been very few attempts to enhance electrical transport properties, i.e., the power factor. Here we use nanochemistry to stabilize bulk bismuth telluride (Bi2Te3) that violates phase equilibrium, namely, phase-pure n-type K0...
October 20, 2016: Journal of the American Chemical Society
Linqi Zong, Yan Jin, Chang Liu, Bin Zhu, Xiaozhen Hu, Zhenda Lu, Jia Zhu
Alloy anodes, particularly silicon, have been intensively pursued as one of the most promising anode materials for the next generation lithium-ion battery primarily because of high specific capacity (>4000 mAh/g) and elemental abundance. In the past decade, various nanostructures with porosity or void space designs have been demonstrated to be effective to accommodate large volume expansion (∼300%) and to provide stable solid electrolyte interphase (SEI) during electrochemical cycling. However, how to produce these building blocks with precise morphology control at large scale and low cost remains a challenge...
November 9, 2016: Nano Letters
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