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Measuring thermoelectric property of nano-heterostructure

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Chinese Physics B 2011年第10期20卷 379-383页

作者：路红亮张晨栋蔡金明高敏邹强郭海明高鸿钧 Beijing National Laboratory for Condensed Matter Physics and Institute of Physics Chinese Academy of Sciences

A method of measuring the thermoelectric power of nano-heterostructures based on four-probe scanning tunneling microscopy is presented. The process is composed of the in-situ fabrication of a tungsten-indium tip, the precise control of the tip-sample contact and the identification of thermoelectric potential. When the temperature of the substrate is elevated, while that of the tip is kept at room temperature, a thermoelectric potential occurs and can be detected by a current voltage measurement. As an example of its application, the method is demonstrated to be effective to measure the thermoelectric power in several systems. A Seebeck coefficient of tens of IxV/K is obtained in graphene epitaxially grown on Ru （0001） substrate and the thermoelectric potential polarity of this system is found to be the reverse of that of bare Ru （0001） substrate.

关键词： thermoelectric property four-probe scanning tunneling microscope graphene nano-heterostructure

Ultrahigh power factors in P-type 1T-ZrX_2(X=S, Se)single layers

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Science Bulletin 2017年第22期62卷 1530-1537页

作者： Ying-Xiang Zhen Ming Yang Hang Zhang Guang-Sheng Fu Jiang-Long Wang Shu-Fang Wang Rui-Ning Wang Hebei Key Laboratory of Optic-Electronic Information and Materials College of Physics Science and TechnologyHebei University Institute of Engineering Thermophysics Chinese Academy of Sciences

The thermoelectric performances of 1 T-ZrX_2(X=S and Se) single layers were investigated using a combination of density functional calculations and semi-classical Boltzmann transport theory. Because of the high hole mobilities at 300 K, ultrahigh power factors(PF = S^2σ) were found in the P-type compounds;these values were ~ 11.95 and ~13.58 mWK ~2 m^1 for 1T-ZrS_2 and 1T-ZrSe_2 single layers, ***, because of the Lorenz relation between the electrical conductivity(σ) and an electron's thermal conductivity(K_(el)) given by the Wiedemann-Franz law, the electronic figures of merit(Z_(el)T = PF T/K_(el)) at 300 K were approximately 0.67 and 0.75 for the N-and P-type 1T-ZrSe_2, respectively. In addition, the lattice thermal conductivities(K_(Ph)) were calculated, giving values of ~1.43 and ~0.97 W K ~1 m^1 for 1T-ZrS_2 and 1T-ZrSe_2 single layers, respectively. Therefore, because of the lower K_(Ph)/K_(el) ratio, the P-type 1T-ZrX_2 single layers possess higher fngure-of-merits(ZT = Z_(el)T/(1+(K_(Ph)/K_(el))) than their counterparts. This signifies that the P-type samples demonstrate better thermoelectric performance than the N-type ones. The thermoelectric properties of metastable 2H-ZrX_2(X = S and Se) single layers were also investigated.

关键词： thermoelectric property Zirconium dichalcogenides Density functional theory Boltzmann-transport theory

Electronic Structures and thermoelectric Properties of Two-Dimensional MoS2/MoSe2 Heterostructures

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Chinese Journal of Chemical Physics 2016年第4期29卷 445-452,I0001页

作者：吴天敏徐瑞雪郑晓庄巍中国科学技术大学合肥微尺度物质科学国家实验室筹合肥230026 中国科学院福建物质结构研究所结构化学国家重点实验室福州350002

thermoelectric properties of bulk and bilayer two-dimensional （2D） MoS2/MoSe2 het- erostructures are investigated using density functional theory in conjunction with semi- classical Boltzmann transport theory. It is predicted that the bulk 2D heterostructures could considerably enhance the thermoelectric properties as compared with the bulk MoSe2. The enhancement originates from the reduction in the band gap and the presence of interlayer van der Waals interactions. We therefore propose the 2D MoS2/MoSe2 heterostructures as a possible candidate material for thermoelectric applications.

关键词： Heterostructures thermoelectric property Density functional theory Boltz-mann transport theory

High thermoelectric and mechanical performance in the n-type polycrystalline SnSe incorporated with multi-walled carbon nanotubes

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Journal of Materials Science & Technology 2022年第19期114卷 55-61页

作者： Xin-Yu Mao Xiao-Lei Shi Liang-Chuang Zhai Wei-Di Liu Yue-Xing Chen Han Gao Meng Li De-Zhuang Wang Hao Wu Zhuang-Hao Zheng Yi-Feng Wang Qingfeng Liu Zhi-Gang Chen State Key Laboratory of Materials-Oriented Chemical Engineering College of Chemical EngineeringNanjing Tech UniversityNanjing 211816China Centre for Future Materials University of Southern QueenslandSpringfield CentralBrisbane4300Australia School of Chemistry and Physics Queensland University of TechnologyBrisbaneQLD 4000Australia Australian Institute for Bioengineering and Nanotechnology The University of QueenslandBrisbaneQLD 4072Australia Shenzhen Key Laboratory of Advanced Thin Films and Applications Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong ProvinceCollege of Physics and Optoelectronic EngineeringShenzhen UniversityShenzhen 518060China Key Laboratory of Material Physics of Ministry of Education School of Physics and MicroelectronicsZhengzhou UniversityZhengzhou 450052China School of Mechanical and Mining Engineering The University of QueenslandSt LuciaBrisbaneQLD 4072Australia College of Materials Science and Engineering Nanjing Tech UniversityNanjing 211816China Jiangsu Collaborative Innovation Center for Advanced Inorganic Function Composites Nanjing Tech UniversityNanjing 211816China CAS Key Laboratory of Carbon Materials Institute of Coal ChemistryChinese Academy of SciencesTaiyuan 030001China

In this study,we introduce multi-walled carbon nanotubes(MWCNTs)in Pb/I co-doped n-type polycrys-tal SnSe to simultaneously improve its thermoelectric and mechanical properties for the first *** introduced MWCNTs act as the“bridges”to accelerate the electron carrier transport between SnSe grains,leading to significantly increased electrical conductivity from 32.6 to 45.7 S cm^(−1) at 773 K,which con-tributes to an enhanced power factor of∼5.0μW cm^(−1) K^(−2) at this *** MWCNTs possess high intrinsic thermal conductivities,these MWCNTs,acting as nanoinclusions in the SnSe matrix to form the dense interfaces between SnSe and MWCNTs,provide extra heat-carrying phonon scattering centers,leading to a slightly reduced lattice thermal conductivity of only 0.34 W m^(−1) K^(−2) at 773 K and in turn,a high ZT of∼1.0 at this ***,the introduced MWCNTs can simultane-ously act as the“binders”to bond adjacent grains,significantly improving the mechanical properties of SnSe by boosting its Vickers hardness from 39.5 to *** work indicates that our facile approach can achieve high thermoelectric and mechanical properties in n-type SnSe polycrystals with a considerable potential for applying to thermoelectric devices as n-type elements.

关键词： thermoelectric property SnSe N-type Multi-walled carbon nanotubes Mechanical property

Probing the thermoelectric transport properties of n-type Bi_2Te_3 close to the limit of constitutional undercooling

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Chinese Physics B 2014年第11期23卷 476-482页

作者：冯松科李双明傅恒志 State Key Laboratory of Solidification Processing Northwestern Polytechnical University

Bulk n-type Bi2Te3 single crystals with optimized chemical composition were successfully prepared by a high temperature-gradient directional solidification method. We investigate the influence of alloy microstructure, chemical composition, and growth orientation on the thermoelectric transport properties. The results show that the composition of single-crystal Bi2Te3 alloy, along the c axis direction, could be slightly tuned by changing the growth rate of the crystal. At a rate of 18 mm/h, the formed Bi2Te3 crystal exhibits good thermoelectric properties. At 300 K, a maximum Seebeck coefficient of -245 μV/K and an electrical conductivity of 5.6 × 10 4 S/m are acquired. The optimal power factor is ob- tained as 3.3 × 10 -3 W/K2m, with a figure of merit of 0.74. It can be attributed to the increased tellurium allocation in the Bi2Te3 alloys, as verified well by the density functional theory caLculations.

关键词： thermoelectric property directional solidification Bi2Te3 density functional theory

Electrical transport and thermoelectric properties of Ni-doped perovskite-type YCo_(1-x)Ni_xO_3 (0 ≤ x ≤ 0.07) prepared by sol-gel process

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Chinese Physics B 2013年第5期22卷 456-461页

作者：刘义李海金张清李勇刘厚通 School of Mathematics and Physics Anhui University of Technology

Electrical transport and thermoelectric properties of Ni-doped YCOl-xNixO3 （0 ≤ x ≤0.07）, prepared by using the sol-gel process, are investigated in a temperature range from 100 to 780 K. The results show that with the increase of Ni doping content, the values of DC resistivity of YCo 1-xNixO3 decrease, but carder concentration increases. The temperature dependences of the resistivity for YCOl-xNixO3 are found to follow a relation of lnp o, lIT in a low-temperature range （LTR）（T 〈- 304 K for x = 0; - 230 K 〈 T 〈- 500 K for x = 0.02, 0.05, and 0.07） and high-temperature range （HTR）（T 〉-655 K for all compounds）, respectively. The estimated apparent activation energies for conduction Eal in LRT and Ea2 in HTR are both found to decrease monotonically with doping content increasing. At very low temperatures （T 〈-230 K）, Mott＇s law is observed for YCOl-xNixO3 （x≥ 0.02）, indicating that considerable localized states form in the heavy doping compounds. Although the Seebeck coefficient of the compound decreases after Ni doping, the power factor of YCOl-xNixO3 is enhanced remarkably in a temperature range from 300 to 740 K, i.e., a 6-fold increase is achieved at 500 K for YCo0.98Ni0.0203, indicating that the high-temperature thermoelectric property of YCoO3 can be improved by partial substitution of Ni for Co.

关键词： perovskite cobalt oxides sol-gel process electrical transport thermoelectric property

Rapid synthesis of CoSb_3 by MA-SPS and its thermoelectric properties

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Rare Metals 2005年第3期24卷 257-260页

作者： LIU Kegao XIANG Dong ZHANG Jiuxing School of Materials Science and Engineering Shandong University of Architecture and Engineering Jinan 250101 China School of Materials and Engineering Beijing University of Technology Beijing 100022 China

Bulk CoSb3 with single phase was synthesized by mechanical alloying and spark plasma sintering （MA-SPS）. The thermoelectric properties of bulk CoSb3 prepared by different technologies were investigated. All samples have the character of typical semiconductor electricity and their thermoelectric figures of merit （ZT） get the maximum values at 400℃. The highest ZT value is 0.0571, belonging to the sample sintered at 600℃ among all samples at all temperatures.

关键词： thermoelectric property spark plasma sintering CoSb3

thermoelectric properties of Bi_(0.5)Sb_(1.5)Te_3/polyaniline composites prepared by mechanical blending and in-situ polymerization

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中国有色金属学会会刊：英文版 2001年第6期11卷 876-878页

作者：胡淑红裴浩东赵新兵浙江大学材料科学与工程系硅材料科学国家重点实验室浙江杭州 310027

Bi 0.5 Sb 1.5 Te 3/polyaniline composites were prepared by mechanical blending and in situ polymerization, and their transport properties were measured. It was found that for the composites with 1%, 3%, 5% and 7% polyaniline (mass fraction) respectively, which were prepared by mechanical blending, the power factors decrease by about 30%, 50%, 55% and 65% compared with the Bi 0.5 Sb 1.5 Te 3 samples, which is mainly due to the remarkable decreases of the electrical conductivity. The electrical conductivity and power factor of the composites samples with 7% polyaniline prepared by in situ polymerization are higher by about 65% and 60%, respectively, than that of the corresponding samples prepared by mechanical blending.

关键词： thermoelectric property Bi 0.5 Sb 1.5 Te 3/polyaniline composite mechanical blending in situ polymerization

Synthesis and thermoelectric Properties of Ca_(2.6)Nd_ ( 0.4)Co_4O_9 Compound

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Journal of Rare Earths 2004年第1期22卷 165-167页

作者：车平张艳薄其兵冯静王静平孟健 Key Laboratory of Rare Earth Chemistry and Physics

The layered cobaltite Ca 2.6Nd 0.4Co 4O 9 was synthesized by the solid-state reaction. Their crystal structure was determined by the X-ray powder diffraction and CELL program. The prepared Ca 2.6Nd 0.4Co 4O 9 compound has the monoclinic symmetry. The electrical conductivity and Seebeck coefficient were measured from room temperature to 700 ℃ in air. Both the properties increase while rising temperature. The thermoelectric power of Ca 2.6Nd 0.4Co 4O 9 is about 242 4 μV·K -1. The results imply a promising way to enhance the thermoelectric properties of the layered cobaltite oxides by optimizing their composition and microstructure.

关键词： inorganic chemistry thermoelectric property layered cobaltite Seebeck coefficient Ca 2.6Nd 0.4Co 4O 9 compound rare earths