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1.
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
2.
3.
A New Strategy for Realizing the Conversion of “Homo–Hetero–Homo” Heteroepitaxial Growth in Bi2Te3 and the Thermoelectric Performance
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Dr. Wei Guo Jianmin Ma Jiaqin Yang Di Li Qing Qin Caiying Wei Prof. Wenjun Zheng 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(19):5657-5664
Uncovering the reason for structure‐dependent thermoelectric performance still remains a big challenge. A low‐temperature and easily scalable strategy for synthesizing Bi2Te3 nanostring hierarchical structures through solution‐phase reactions, during which there is the conversion of “homo–hetero–homo” in Bi2Te3 heteroepitaxial growth, is reported. Bi2Te3 nanostrings are obtained through the transformation from pure Bi2Te3 hexagonal nanosheets followed by Te?Bi2Te3 “nanotop” heterostructures to Bi2Te3 nanostrings. The growth of Bi2Te3 nanostrings appears to be a self‐assembly process through a wavy competition process generated from Te and Bi3+. The conversion of homo–hetero–homo opens up new platforms to investigate the wet chemistry of Bi2Te3 nanomaterials. Furthermore, to study the effect of morphologies and hetero/homo structures, especially with the same origin and uniform conditions on their thermoelectric properties, the thermoelectric properties of Bi2Te3 nanostrings and Te?Bi2Te3 heterostructured pellets fabricated by spark plasma sintering have been investigated separately. 相似文献
4.
S. Michel S. Diliberto N. Stein B. Bolle C. Boulanger 《Journal of Solid State Electrochemistry》2008,12(1):95-101
Composition modulated Bi2(Te1−xSex)3 thin films were prepared on stainless steel substrates by cathodic electrodeposition. The composition was dependent on the
deposition conditions. It was possible to obtain, in the same electrolyte, films with either an excess or a deficiency of
bismuth in relation to stoichiometric Bi2(Te0.9Se0.1)3 by changing the deposition potential or the applied current density. The excess of bismuth was reached at the highest cathodic
conditions. The variation of the crystallographic axis and the morphology with a granular structure were correlated with the
presence of the Bi enrichment in the ternary. The crystallographic texture of bismuth telluride films was studied according
to the electrodeposition conditions. The films presented a fibre texture, and a main orientation {11.0} was observed. Electrical
and thermoelectric properties of a Bi1.98Te2.67Se0.39 film were measured and showed an n-type behaviour. 相似文献
5.
The electrolyses of solutions of bismuth oxide and tellurium oxide in nitric acid with molar ratios of Bi:Te=3:3–4:3 lead
to cathodic deposits of films of bismuth telluride (Bi2Te3), an n-type semiconductor. Current densities of 2–5 mA/cm2 were applied. Voltammetric investigations showed that Bi2Te3 deposition occurred at potentials more negative than −0.125 V (Ag/AgCl, 3 M KCl). The deposit was identified as bismuth telluride
(γ-phase) by X-ray analysis. Hall-effect measurements verified the n-type semiconducting behaviour. The films can be deposited
in microstructures for thermoelectric microdevices like thermoelectric batteries or thermoelectric sensors. 相似文献
6.
Single-crystal Bi2Te3-Te nanocomposites with heterostructure were synthesized using a two-step solvothermal process in the presence of ethylenediaminetetraacetic acid disodium salt. The first step is the formation of the Te nanorods and the second step is to grow the Bi2Te3 sheets off the Te rods surface to form the Bi2Te3-Te nanocomposites. The products were characterized by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. We demonstrate a method of an epitaxial growth of Bi2Te3 nanosheets perpendicular to the axis of the central Te rod and a formation process of Bi2Te3-Te nanocomposites is also proposed. 相似文献
7.
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
8.
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
9.
Qi Zhang Teng Fang Feng Liu Airan Li Yehao Wu Tiejun Zhu Xinbing Zhao 《化学:亚洲杂志》2020,15(18):2775-2792
Bi2Te3‐based solid solutions, which have been widely used as thermoelectric (TE) materials for the room temperature TE refrigeration, are also the potential candidates for the power generators with medium and low‐temperature heat sources. Therefore, depending on the applications, Bi2Te3‐based materials are expected to exhibit excellent TE properties in different temperature ranges. Manipulating the point defects in Bi2Te3‐based materials is an effective and important method to realize this purpose. In this review, we focus on how to optimize the TE properties of Bi2Te3‐based TE materials in different temperature ranges by defect engineering. Our calculation results of two‐band model revel that tuning the carrier concentration and band gap, which is easily realized by defects engineering, can obtain better TE properties at different temperatures. Then, the typical paradigms about optimizing the TE properties at different temperatures for n‐type and p‐type Bi2Te3‐based ZM ingots and polycrystals are discussed in the perspective of defects engineering. This review can provide the guidance to improve the TE properties of Bi2Te3‐based materials at different temperatures by defects engineering. 相似文献
10.
Creating Zipper‐Like van der Waals Gap Discontinuity in Low‐Temperature‐Processed Nanostructured PbBi2nTe1+3n: Enhanced Phonon Scattering and Improved Thermoelectric Performance
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Prof. Dr. Biao Xu Dr. Tianli Feng Zhe Li Prof. Dr. Lin Zhou Prof. Dr. Sokrates T. Pantelides Prof. Dr. Yue Wu 《Angewandte Chemie (International ed. in English)》2018,57(34):10938-10943
Nanoengineered materials can embody distinct atomic structures which deviate from that of the bulk‐grain counterpart and induce significantly modified electronic structures and physical/chemical properties. The phonon structure and thermal properties, which can also be potentially modulated by the modified atomic structure in nanostructured materials, however, are seldom investigated. Employed here is a mild approach to fabricate nanostructured PbBi2nTe1+3n using a solution‐synthesized PbTe‐Bi2Te3 nano‐heterostructure as a precursor. The as‐obtained monoliths have unprecedented atomic structure, differing from that of the bulk counterpart, especially the zipper‐like van der Waals gap discontinuity and the random arrangement of septuple‐quintuple layers. These structural motifs break the lattice periodicity and coherence of phonon transport, leading to ultralow thermal conductivity and excellent thermoelectric z T. 相似文献
11.
G. R. Gurbanov I. B. Bakhtiyarly R. D. Kurbanova 《Russian Journal of Inorganic Chemistry》2010,55(7):1149-1152
This is the first study of the SnSbBiTe4-2Bi2Te3 join of the SnTe-Bi2Te3-Sb2Te3 quasi-ternary system by the methods of complex physicochemical analysis over a wide range of concentrations. A phase diagram
was constructed for the title quasi-binary join. The system was found to be of the eutectic type; the eutectic coordinates
are 65 mol % Bi2Te3 and 675 K. The starting components were shown to form solid solutions with extents of 20 mol %. Alloys with compositions
lying within the Bi2Te3-based solid solution region were found to be n-type semiconductors. 相似文献
12.
L. E. Shelimova O. G. Karpinskii V. I. Kosyakov V. A. Shestakov V. S. Zemskov F. A. Kuznetsov 《Journal of Structural Chemistry》2000,41(1):81-87
Formation of the homologous series of layered compounds nBi2-mBi2Te3 and nGeTe mBi2Te3 is analyzed. For both series, the crystal structure contains two-layer (Bi2 or GeTe) and five-layer (Bi2Te3) packets perpendicular to the c axis. Unlike the Bi2 packets, the GeTe packets do not retain their individuality during crystal structure formation; they are linked to the Bi2Te3 five-layer packets to form new multilayer packets leading to a considerable change in the character of interatomic interactions.
Translated from Zhumal Struktumoi Khimii, Vol. 41, No. 1, pp. 97-105, January–February, 2000. 相似文献
13.
Solution‐Based Synthesis of Layered Intergrowth Compounds of the Homologous PbmBi2nTe3n+m Series as Nanosheets
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Arindom Chatterjee Dr. Kanishka Biswas 《Angewandte Chemie (International ed. in English)》2015,54(19):5623-5627
Layered intergrowth compounds in the homologous PbmBi2nTe3n+m family are interesting because they are examples of natural heterostructures. We present a simple solution‐based synthesis of two‐dimensional nanosheets of PbBi2Te4, Pb2Bi2Te5, and PbBi6Te10 layered intergrowth compounds, which are members of the PbmBi2nTe3n+m [that is, (PbTe)m(Bi2Te3)n] homologous series. Few‐layer nanosheets exhibit narrow optical band gaps (0.25–0.7 eV) with semiconducting electronic‐transport properties. 相似文献
14.
The Influence of Nanoscale Heterostructures on the Thermoelectric Properties of Bi‐substituted Tl5Te3
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Frank Heinke Lucien Eisenburger Robert Schlegel Stefan Schwarzmüller Oliver Oeckler 《无机化学与普通化学杂志》2017,643(6):447-454
Tl4.5Bi0.5Te3 crystallizes in a distorted variant of the Tl5Te3 structure type in the space group I4/m. The symmetry reduction compared to Tl5Te3 (space group I4/mcm) is a consequence of cation ordering as shown by resonant X‐ray scattering using synchrotron radiation. Tl and Bi predominantly occupy one Wyckoff site each. This ordering is accompanied by displacements of Te atoms. The influence of nanostructuring on the thermoelectric performance of Tl4.5Bi0.5Te3 was investigated for the new composite model system Tl4.5Bi0.5Te3 – TlInTe2. For the nominal composition (Tl4.5Bi0.5Te3)0.6(TlInTe2)0.4, the thermoelectric Figure of merit ZT reaches 0.8 at 325 °C. Nanoscaled precipitates with sizes of about 100–200 nm probably have beneficial influence on the thermal conductivity at this temperature. 相似文献
15.
Bi2Te3-Te arrays with sheet-rod multiple heterostructure were obtained in large scale, using Te nanorod arrays as the in-situ templates under solvothermal process. The array is formed by the ordered Bi2Te3-Te rods where Bi2Te3 sheets distribute from the top face to the bottom face along the Te rod vertically. The microstructure of the heterostructure was studied through X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The electrical conductivity and Seebeck coefficient of the arrays were also studied. The course of reaction was monitored so as to propose a possible growth mechanism of such novel heterostructure. The key for the preparation of such heterostructure is to balance the velocity between the dissolution of Te rods and the formation of Bi2Te3 sheets. This synthetic approach could be promising to prepare self-assembled low-dimensional nanoarrays of metals and semiconductors with high yield. 相似文献
16.
Bismuth tellurides is one of the most promising thermoelectric (TE) material candidates in low-temperature application circumstances, but the n-type thermoelectric property is relatively low compared to the p-type counterpart and still needs to be improved. Herein, we incorporated different copper selenides (CuSe, Cu3Se2 and Cu2−xSe) into a Bi2Te3 matrix to create the alloy by grinding and successive sintering to enable higher thermoelectric performance. The results demonstrated that all alloys achieved n-type TE characteristics and Bi2Te3-CuSe exhibited the best Seebeck coefficient and power factor among them. Along with the low thermal conductivity, the maximum dimensionless TE figure of merit (ZT) value of 1.64 at 573 K was delivered for Bi2Te3-CuSe alloy, which is among the best reported results in the n-type Bi2Te3-based TE materials to the best of our knowledge. The improved TE properties should be related to the co-doping process of Se and Cu. Our investigation shows a new method to enhance the performance of n-type TE materials by appropriate co-doping or alloying. 相似文献
17.
J.L. Cui W.J. Xiu L.D. Mao P.Z. Ying X. Qian 《Journal of solid state chemistry》2007,180(3):1158-1162
Ag-doped n-type (Bi2Te3)0.9-(Bi2−xAgxSe3)0.1 (x=0-0.4) alloys were prepared by spark plasma sintering and their physical properties evaluated. When at low Ag content (x=0.05), the temperature dependence of the lattice thermal conductivity follows the trend of (Bi2Te3)0.9-(Bi2Se3)0.1; while at higher Ag content, a relatively rapid reduction above 400 K can be observed due possibly to the enhancement of scattering of phonons by the increased defects. The Seebeck coefficient increases with Ag content, with some loss of electrical conductivity, but the maximum dimensionless figure of merit ZT can be obtained to be 0.86 for the alloy with x=0.4 at 505 K, about 0.2 higher than that of the alloy (Bi2Te3)0.9-(Bi2Se3)0.1 without Ag-doping. 相似文献
18.
The valence band (VB) density of states and the binding energies of the weakly bound core levels have been measured by XUV photoelectron spectroscopy using synchrotron radiation for four V–VI layered compounds. Chemical shifts of the core levels are determined which support the partial ionicity of the bonds involved. The chemical shifts of the emission from two unequivalent crystal sites were shown to differ by less than 30 meV for the compounds Bi2Te3, Bi2Se3 and Sb2Te3.VB and core-level photoemission spectra for the V–VI compounds Bi2Te3, Bi2Se3, Sb2Te3 and Se2Te2Se have been presented. Chemical shifts of the Te 4d, Bi 5d, Sb 4d and Se 3d levels were determined, indicating partial ionicity of the mainly covalent bonds involved. Chemical-shift differences originating from atoms at two different crystal sites are <30 meV. In a simple model this implies that similar charge transfers do occur even though completely different bond orbitals were proposed for the and the AB(2) bonds. Finally, the fact that no surface core-level shifts were observed tends to confirm the very weak influence of the van der Waals-like bonds on the B(2) atoms. 相似文献
19.
Jean-Claude Champarnaud-Mesjard Bernard Frit Abdeslam Chagraoui Abdelmjid Taïri 《无机化学与普通化学杂志》1996,622(11):1907-1912
Bi2Te2WO10 crystallises in the monoclinic system (space group C2/c, Z = 4) with a = 12.4972(7) Å, b = 5.6414(3) Å, c = 12.2705(6) Å and β = 91.38(3)°. The structure has been solved by means of single crystal X-ray diffraction data analysis. The reliability factors are R1 = 0.030 and wR2 = 0.065 for 1258 structure factors and 70 parameters. The Bi2Te2WO10 crystal structure can be described as a regular stacking along the Ox axis of polyhedral layers with the stereochemically active lone pairs E of the BiIII and TeIV atoms all located between these layers. The cohesion of the three-dimensional network is therefore only ensured between succesive layers by weak Bi? O(5) bonds. 相似文献
20.
Xiaochuan Xu Chunfen Wang Qin Yao Chude Feng 《Journal of solid state chemistry》2005,178(6):2163-2166
Heterostructured polyaniline/Bi2Te3 nanowires have been prepared by chemical and electrochemical reactions on a porous alumina template. Its morphology and structure have been studied by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and electron probe microanalysis. The microscope analysis reveals that Bi2Te3 is well enveloped in polyaniline tubules in pores of alumina template. This microscopic material shows possible application in microthermoelectric device. 相似文献