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Daniel Tordera, Dan Zhao, Anton V Volkov, Xavier Crispin, Magnus P Jonsson
Non-radiative decay of plasmons in metallic nanostructures offers unique means for light-to-heat conversion at the nanoscale. Typical thermoplasmonic systems utilize discrete particles, while metal nanohole arrays were instead considered suitable as heat sinks to reduce heating effects. By contrast, we show for the first time that, under uniform broadband illumination (e.g. the sun), ultrathin plasmonic nanohole arrays can be highly competitive plasmonic heaters and provide significantly higher temperatures than analogous nanodisk arrays...
April 25, 2017: Nano Letters
Mattia Sist, Carlo Gatti, Peter Nørby, Simone Cenedese, Hidetaka Kasai, Kenichi Kato, Bo B Iversen
The discovery of the ultra-high thermoelectric figure of merit of 2.6 in SnSe has drawn attention to other lead-free IV-VI orthorhombic semiconductors. GeSe has been predicted to possess thermoelectric performances comparable to SnSe. Here, a complete structural study is reported of GeSe with temperature by means of high-resolution synchrotron powder X-ray diffraction. In the orthorhombic phase, the evolution of the bond distances with temperature is shown to deviate significantly with respect to SnSe. Analysis of the chemical bonding within the Quantum Theory of Atoms in Molecules shows that GeSe is ionic with van der Waals interlayer interactions...
April 25, 2017: Chemistry: a European Journal
Carrie L McCarthy, Richard L Brutchey
Macroelectronics is a major focus in electronics research and is driven by large area applications such as flat panel displays and thin film solar cells. Innovations for these technologies, such as flexible substrates and mass production, will require efficient and affordable semiconductor processing. Low-temperature solution processing offers mild deposition methods, inexpensive processing equipment, and the possibility of high-throughput processing. In recent years, the discovery that binary "alkahest" mixtures of ethylenediamine and short chain thiols possess the ability to dissolve bulk inorganic materials to yield molecular inks has lead to the wide study of such systems and the straightforward recovery of phase pure crystalline chalcogenide thin films upon solution processing and mild annealing of the inks...
April 25, 2017: Chemical Communications: Chem Comm
Renee Kroon, David Kiefer, Dominik Stegerer, Liyang Yu, Michael Sommer, Christian Müller
Molecular doping of organic semiconductors is critical for optimizing a range of optoelectronic devices such as field-effect transistors, solar cells, and thermoelectric generators. However, many dopant:polymer pairs suffer from poor solubility in common organic solvents, which leads to a suboptimal solid-state nanostructure and hence low electrical conductivity. A further drawback is the poor thermal stability through sublimation of the dopant. The use of oligo ethylene glycol side chains is demonstrated to significantly improve the processability of the conjugated polymer p(g4 2T-T)-a polythiophene-in polar aprotic solvents, which facilitates coprocessing of dopant:polymer pairs from the same solution at room temperature...
April 24, 2017: Advanced Materials
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
D J Voneshen, H C Walker, K Refson, J P Goff
The suppression of transverse phonons by liquidlike diffusion in superionic conductors has been proposed as a means to dramatically reduce thermal conductivity in thermoelectric materials [H. Lui et al. Nat. Mater. 11, 422 (2012)NMAACR1476-112210.1038/nmat3273]. We have measured the ion transport and lattice dynamics in the original phonon-liquid electron-crystal Cu_{2}Se using neutron spectroscopy. We show that hopping time scales are too slow to significantly affect lattice vibrations and that the transverse phonons persist at all temperatures...
April 7, 2017: Physical Review Letters
Zhen He, Yuan Yang, Jian-Wei Liu, Shu-Hong Yu
Tellurium (Te) is a rare element in trace amounts of about one part per billion, comparable to that of platinum and ranked 75th in the abundance of the elements in the earth crust. Te nanostructures, as narrow bandgap semiconductors, have numerous potential applications in the fabrication of many modern devices. The past decades have witnessed an explosion in new strategies for synthesizing diverse emerging Te nanostructures with controlled compositions, sizes, shapes, and structures. Their structure-determined nature makes functional Te nanomaterials an attractive candidate for modern applications...
April 20, 2017: Chemical Society Reviews
Radoslaw Chmielowski, Sandip Bhattacharya, Stéphane Jacob, Daniel Péré, Alain Jacob, Kenzo Moriya, Bruno Delatouche, Pascal Roussel, Georg Madsen, Gilles Dennler
In order to reduce the thermal conductivity of CoSbS, a newly developed thermoelectric semiconductor, we have aimed at intentionally induce atomic disorder in its structure. This endeavor was guided by Density Functional Theory(DFT) calculations which indicated that substituting sulfur with selenium might be easily achievable experimentally because of the low formation energy of this point defect. Thereby, CoSbS1-xSex compounds having 0 ≤ x ≤ 1 have been synthesized by solid state reaction. Besides the expected semiconducting paracostibite phase, we have observed the appearance of a semimetallic costibite phase, never reported experimentally before...
April 20, 2017: Scientific Reports
Gangjian Tan, Shiqiang Hao, Jing Zhao, Chris Wolverton, Mercouri G Kanatzidis
We report electron-doped AgBi3S5 as a new type of high-performance non-toxic thermoelectric material. This compound features exceptionally low lattice thermal conductivities of 0.5-0.3 Wm-1K-1 in the temperature range of 300-800 K, which is ascribed to its unusual vibrational properties: "double rattling" phonon modes associated with Ag and Bi atoms. Chlorine doping at anion sites acts as an efficient electron donor, significantly enhancing the electrical properties of AgBi3S5. In the carrier concentration range (5×1018-2×1019 cm-3) investigated in this study, the trends in Seebeck coefficient can be reasonably understood using a single parabolic band model with the electron effective mass of 0...
April 18, 2017: Journal of the American Chemical Society
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
Hulei Yu, Wenxin Lao, Lijuan Wang, Kuo Li, Yue Chen
Tin-selenium binary compounds are important semiconductors that have attracted much interest for thermoelectric and photovoltaic applications. As tin has a +2 or +4 oxidation state and selenium has an oxidation number of -2, only SnSe and SnSe_{2} have been observed. In this work, we show that the chemical bonding between tin and selenium becomes counterintuitive under pressures. Combining evolutionary algorithms and density functional theory, a novel cubic tin-selenium compound with an unexpected stoichiometry 3∶4 has been predicted and further synthesized in laser-heated diamond anvil cell experiments...
March 31, 2017: Physical Review Letters
Mandvi Saxena, Tanmoy Maiti
Increasing electrical conductivity in oxides, which are inherently insulators, can be a potential route in developing oxide-based thermoelectric power generators with higher energy conversion efficiency. In the present work, environmentally friendly non-toxic double perovskite LaxSr2-xTiMoO6 (LSTM) ceramics were synthesized using a solid-state reaction route by optimizing the sintering temperature and atmosphere for high temperature thermoelectric applications. Rietveld refinement of XRD data confirmed a single-phase solid solution with a cubic structure in these double perovskites with the space-group Pm3[combining macron]m...
April 12, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Mohammed Noori, Hatef Sadeghi, Colin J Lambert
If high efficiency organic thermoelectric materials could be identified, then these would open the way to a range of energy harvesting technologies and Peltier coolers using flexible and transparent thin-film materials. We have compared the thermoelectric properties of three zinc porphyrin (ZnP) dimers and a ZnP monomer and found that the "edge-over-edge" dimer formed from stacked ZnP rings possesses a high electrical conductance, negligible phonon thermal conductance and a high Seebeck coefficient of the order of 300 μV K(-1)...
April 20, 2017: Nanoscale
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
Zhenhua Zou, Jinwei Dong, Michael A Menarguez, Xiangming Xiao, Yuanwei Qin, Russell B Doughty, Katherine V Hooker, K David Hambright
Oklahoma contains the largest number of manmade lakes and reservoirs in the United States. Despite the importance of these open surface water bodies to public water supply, agriculture, thermoelectric power, tourism and recreation, it is unclear how these water bodies have responded to climate change and anthropogenic water exploitation in past decades. In this study, we used all available Landsat 5 and 7 images (16,000 scenes) from 1984 through 2015 and a water index- and pixel-based approach to analyze the spatial-temporal variability of open surface water bodies and its relationship with climate and water exploitation...
April 7, 2017: Science of the Total Environment
Claudia Coughlan, Maria Ibáñez, Oleksandr Dobrozhan, Ajay Singh, Andreu Cabot, Kevin M Ryan
This review captures the synthesis, assembly, properties, and applications of copper chalcogenide NCs, which have achieved significant research interest in the last decade due to their compositional and structural versatility. The outstanding functional properties of these materials stems from the relationship between their band structure and defect concentration, including charge carrier concentration and electronic conductivity character, which consequently affects their optoelectronic, optical, and plasmonic properties...
April 10, 2017: Chemical Reviews
Shi-Jun Liang, Bo Liu, Wei Hu, Kun Zhou, L K Ang
Seeking for thermoelectric (TE) materials with high figure of merit (or ZT), which can directly converts low-grade wasted heat (400 to 500 K) into electricity, has been a big challenge. Inspired by the concept of multilayer thermionic devices, we propose and design a solid-state thermionic devices (as a power generator or a refrigerator) in using van der Waals (vdW) heterostructure sandwiched between two graphene electrodes, to achieve high energy conversion efficiency in the temperature range of 400 to 500 K...
April 7, 2017: Scientific Reports
Zhaoyang Lin, Courtney Hollar, Joon Sang Kang, Anxiang Yin, Yiliu Wang, Hui-Ying Shiu, Yu Huang, Yongjie Hu, Yanliang Zhang, Xiangfeng Duan
A solid-state thermoelectric device is attractive for diverse technological areas such as cooling, power generation and waste heat recovery with unique advantages of quiet operation, zero hazardous emissions, and long lifetime. With the rapid growth of flexible electronics and miniature sensors, the low-cost flexible thermoelectric energy harvester is highly desired as a potential power supply. Herein, a flexible thermoelectric copper selenide (Cu2 Se) thin film, consisting of earth-abundant elements, is reported...
March 29, 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
Xi Li, Yves Fautrelle, Zhongming Ren, Rene Moreau
Understanding the macrosegregation formed by applying magnetic fields is of high commercial importance. This work investigates how static magnetic fields control the solute and primary phase distributions in four directionally solidified alloys (i.e., Al-Cu, Al-Si, Al-Ni and Zn-Cu alloys). Experimental results demonstrate that significant axial macrosegregation of the solute and primary phases (i.e., Al2Cu, Si, Al3Ni and Zn5Cu phases) occurs at the initial solidification stage of the samples. This finding is accompanied by two interface transitions in the mushy zone: quasi planar → sloping → quasi planar...
April 3, 2017: Scientific Reports
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