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在N2气保护下,采用电磁感应法制备了添加La的Bi2Te3和Bi0.5Sb1.5Te3。运用X射线粉末衍射、电感耦合等离子光谱和扫描电子显微镜对材料的物相成分和形貌进行了表征。研究了La对Bi2Te3和Bi0.5Sb1.5Te3热电材料的电导率(σ)、Seebeck系数(S)和热导率(κ)的影响。实验结果表明,添加La明显降低了2种材料的热导率,提高了热电优值(ZT),添加La的Bi0.5Sb1.5Te3的热电优值在室温超过了1。 相似文献
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含镧的Bi2Te3基化合物的溶剂热合成及微观结构 总被引:5,自引:1,他引:5
以BiCl3,LaCl3和Te粉为原料,用溶剂热合成法制备了含稀土元素的单相LaxBi4Te6(x≤1)热电材料纳米粉末.研究发现,三元化合物LaxBi4Te6具有与二元Bi2Te3化合物相同的晶体结构和相似的晶格常数。LaxBi4Te6中的La含量随合成温度升高而增加,但与反应时间没有显著关系。LaxBi4Te6合成粉末的颗粒尺寸在30nm左右,并且几乎与反应温度和反应时间没有关系。在120℃合成的粉末基本上为不规则多面体形状,在150℃及以上温度合成的粉末则趋向于薄片状.并存在一些直径在50~80nm之间的纳米管。 相似文献
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Research on Chemical Intermediates - Tellurium nanotube-based bismuth telluride (Te/Bi2Te3) nanocomposite powders have been synthesized by the polyol process using Bi (NO3)3, TeCl4 as the metal... 相似文献
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Chemical and physical reactions during the low temperature aqueous chemical synthesis of nanostructured Bi2Te3 powders were investigated in-situ by pH measurement, color observation of the solution and X-ray diffraction analysis of
the powders. It was found that Bi2Te3 could be synthesized only in a strong alkaline solution. Bi2Te3 nanocapsules were synthesized by the aqueous chemical route at 65 °C with the addition of disodium ethylenediaminetetraacetate
salt. High-resolution transmission electron microscopy observation indicates that the nanocapsules are hollow-structured with
a wall thickness of about 6 nm.
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Translated from CHIMICA SINICA, 2005, 63(16)(in Chinese) 相似文献
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The Seebeck coefficient enhancement due to an increase of density-of-states effective mass of electron has been found in n-type Bi1.9Lu0.1Te3. This enhancement is assumed to be related to forming the narrow and non-parabolic impurity (Lu) band with local maximum of electronic density of states lying near the Fermi level. Minimum in the specific electrical resistivity, ρ, originated from change of conductivity mechanism was observed at temperature Tm ≈ 11 K. Above Tm, the ρ change is due to decrease of electron mobility via acoustic phonon scattering. Below Tm, the variable-range hopping conductivity takes place. The electron hops between the localized states of the impurity energy band occur via tunneling process. Using the temperature and magnetic field dependences of ρ, the localization radius of electron was estimated as ≈6 nm. Two parts in the magnetic field dependence of the electrical resistivity were found at temperature of 2 K. At weak magnetic fields, the ρ change is in agreement with the variable-range hopping conductivity mechanism. At high magnetic fields, the positive and almost linear transverse and longitudinal magnetoresistances were observed at low temperatures. Both variable-range hopping conductivity and positive linear magnetoresistance are characteristics of disordered and inhomogeneous semiconductors. 相似文献
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Cristina V. Manzano Adriana A. Rojas Michelle Decepida Begoña Abad Yazmin Feliz Olga Caballero-Calero Diana-Andra Borca-Tasciuc Marisol Martin-Gonzalez 《Journal of Solid State Electrochemistry》2013,17(7):2071-2078
Bi2Te3 films have been grown by constant and pulsed electrochemical deposition. The pulsed deposition was carried out by alternating between a constant potential (potentiostatic mode) and an open circuit potential (galvanostatic mode, where current density is fixed at 0 mA/cm2). The Harris texture analysis was performed to determine the degree of preferred orientation. The results showed that the films were strongly oriented along (1?1?0) direction. The morphology and compositions of the films were then analyzed. Finally, their Seebeck coefficient and electrical resistivity were measured and used to determine the thermoelectric Power Factor of the films for a temperature range between 57 and 107 °C. 相似文献
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Electrodeposition of ordered Bi2Te3 nanowire arrays. 总被引:9,自引:0,他引:9
A L Prieto M S Sander M S Martín-González R Gronsky T Sands A M Stacy 《Journal of the American Chemical Society》2001,123(29):7160-7161
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Rosalinda Inguanta Salvatore Piazza Carmelo Sunseri 《Electrochemistry communications》2009,11(7):1385-1388
This work shows that it is possible to obtain self-standing Pd nanowires into anodic alumina membranes by a simple metal displacement deposition. By using a proper arrangement, specifically designed in order to optimize the process, polycrystalline Pd nanowires were deposited from a solution containing Pd(NH3)4(NO3)2 as precursor. Morphological analysis showed the formation of perfectly aligned nanowires with a uniform diameter throughout the entire length. This last parameter was controlled by both the deposition time and the ratio between the anodic area (active metal) and the cathodic area (pore bottom). 相似文献
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Stefan Novaconi Paulina Vlazan Iosif Malaescu Iulia Badea Ioan Grozescu Paula Sfirloaga 《Central European Journal of Chemistry》2013,11(10):1599-1605
Nanocrystalline powders of doped Bi2Te3, with Ag (S1 sample), Sb (S2 sample), Sn (S3 sample) ions with different morphology and particle size 30–50 nm were prepared by a ultrasonically assisted hydrothermal method in alkaline aqueous solution with different concentration of NaBH4 as reducing agent at 200°C for 3 hours and 80% fill degree of autoclave. The influence of dopants and hydrothermal treatment conditions on the formation features, phase composition, particle size, morphology and properties of the products were investigated by X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, atomic force microscopy and electrical measurements. This paper reports a comparative study regarding the dopants influence to the shape and size of nano-structured thermoelectric materials. It was found that hydrothermal processing results in formation of low dimensional dispersion of doped Bi2Te3 nanostructures with desired shape and size and high degree of crystallinity with typical semiconductor behavior. 相似文献
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Hsu KF Lal S Hogan T Kanatzidis MG 《Chemical communications (Cambridge, England)》2002,(13):1380-1381
Two new thermoelectric materials of quaternary bismuth telluride CsPb3Bi3Te8 and CsPb4Bi3Te9 are reported, which are members of a homologous series featuring anionic slabs [PbmBi3Te5 + m]- (m = 1-4) of monotonically increasing thickness. 相似文献
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Bakavets Aliaksei Aniskevich Yauhen Ragoisha Genady Mazanik Alexander Tsyntsaru Natalia Cesiulis Henrikas Streltsov Eugene 《Journal of Solid State Electrochemistry》2021,25(12):2807-2819
Journal of Solid State Electrochemistry - Selective electrochemical transformations of bismuth interlayers in (Bi2)m(Bi2Te3)n superlattices can be of interest as a means of thermoelectric materials... 相似文献
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Bi2Te3 nanoparticles (NPs) have been synthesized at 50?°C by a low-cost wet chemical route. The structural properties of product sample were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy. Thermal properties of product sample were investigated by differential scanning calorimetry (DSC), thermogravimetric (TG), and transient plane source techniques. The XRD and selected area electron diffraction of Bi2Te3 NPs result showed the polycrystalline nature with a rhombohedral (R3m) structure of the nanocrystallites. The average grain size of Bi2Te3 NPs was found to be about 30?nm by XRD and TEM measurements. DSC result shows one endothermic peak and one exothermic peak. TG result shows that only 48?% mass loss has occurred in Bi2Te3 sample. The obtained lower thermal conductivity of Bi2Te3 NPs is about 0.3?W m?1 K?1 at room temperature, which is caused by considering the crystalline nature of this material. 相似文献
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《Thermochimica Acta》1987,122(1):135-141
Through X-ray, D.T.A. and microstructural analysis, phase interactions in the Bi2Te3-Bi2Se3 section were investigated and the phase diagram was described. The result was not a simple solid solution region as had been previously supposed. A more complex subsolidus pattern was discovered with two terminal solid solutions α and α' and a zone of demixion.An intermediate phase Bi2Te2Se was confirmed, its properties and conditions of existence described in the new context. 相似文献
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Dr. Guanjun Xiao Dr. Chunye Zhu Prof. Yanming Ma Prof. Bingbing Liu Prof. Guangtian Zou Prof. Bo Zou 《Angewandte Chemie (International ed. in English)》2014,53(3):729-733
There is an urgent need for the development in the field of the magnetism of topological insulators, owing to the necessity for the realization of the quantum anomalous Hall effect. Herein, we discuss experimentally fabricated nanostructured hierarchical architectures of the topological insulator Bi2Te3 without the introduction of any exotic magnetic dopants, in which intriguing room‐temperature ferromagnetism was identified. First‐principles calculations demonstrated that the intrinsic point defect with respect to the antisite Te site is responsible for the creation of a magnetic moment. Such a mechanism, which is different from that of a vacancy defect, provides new insights into the origins of magnetism. Our findings may pave the way for developing future Bi2Te3‐based dissipationless spintronics and fault‐tolerant quantum computation. 相似文献