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1.
Kunal J. Tiwari D. S. Prem Kumar Ramesh Chandra Mallik P. Malar 《Journal of Electronic Materials》2017,46(1):30-39
In this work, quaternary chalcogenide Cu2ZnSnSe4 (CZTSe) was synthesized using a mechanochemical ball milling process and its thermoelectric properties were studied by electrical resistivity, Seebeck coefficient, and thermal conductivity measurements. The synthesis process comprises three steps viz., wet ball milling of the elemental precursors, vacuum annealing, and densification by hot pressing. The purpose of this is to evaluate the feasibility of introducing wet milling in place of vacuum melting in solid state synthesis for the reaction of starting elements. We report the structural characterization and thermoelectric studies conducted on samples that were milled at 300 rpm and 500 rpm. X-ray diffraction (XRD) analysis showed the existence of multiple phases in the as-milled samples, indicating the requirement for heat treatment. Therefore, the ball milled powders were cold pressed and vacuum annealed to eliminate the secondary phases. Annealed samples were hot pressed and made into dense pellets for further investigations. In addition to XRD, energy dispersive spectroscopy (EDS) studies were performed on hot pressed samples to study the composition. XRD and EDS studies confirm CZTSe phase formation along with ZnSe secondary phase. Electrical resistivity and Seebeck coefficient measurements were done on the hot pressed samples in the temperature range 340–670 K to understand the thermoelectric behaviour. Thermal conductivity was calculated from the specific heat capacity and thermal diffusivity values. The thermoelectric figure of merit zT values for samples milled at 300 rpm and 500 rpm are ~0.15 and ~0.16, respectively, at 630 K, which is in good agreement with the values reported for solid state synthesized compounds. 相似文献
2.
Dense samples of the higher boride YB22C2N have been fabricated through the spark plasma sintering (SPS) method with different sintering aids. YB22C2N is a representative of a series of newly discovered rare-earth borocarbonitrides, which may be the long-awaited n-type counterpart of boron carbide, “B4C.” The effect of Si, SiC, Al, and TiC additions on the sintering process of YB22C2N has been studied. The best sintered bodies with densities higher than 90% of theoretical density were obtained by means
of SPS at 1700°C. We show that the additive choice and pressure have an effect on grain size and density. An investigation
of the effect of atmosphere on the sintering behavior has also been carried out. It was found that sinterability is enhanced
under nitrogen atmosphere. Thermoelectric properties of the materials sintered with additives have been evaluated, and we
discuss their dependences on the fabrication process route. 相似文献
3.
Biprodas Dutta Jugdersuren Battogtokh David Mckewon Igor Vidensky Neilanjan Dutta Ian L. Pegg 《Journal of Electronic Materials》2007,36(7):746-752
NaCo2O4 has one of the highest figures of merit among all ceramic thermoelectric materials. Because of its large thermopower and
low resistivity, the ceramic oxide NaCo2O4 is a promising candidate for potential thermoelectric applications. NaCo2O4 is, moreover, a ceramic compound with high decomposition temperature and chemical stability in air and it does not contain
any toxic elements. Like all 3-d transition ions, Co ions have multiple spin and oxidation states. In this investigation,
thermopower and electrical conductivity of NaCo2O4 as a function of substitution of Co by Fe ions were measured. Fe substitution for Co causes resistivity to increase, whereas
the Seebeck coefficient remained nearly invariant, especially above 330 K.
An erratum to this article can be found at 相似文献
4.
Jun-Ling Gao Qun-Gui Du Xiao-Dan Zhang Xin-Qiang Jiang 《Journal of Electronic Materials》2011,40(5):884-888
The output power and conversion efficiency of thermoelectric modules (TEMs) are mainly determined by their material properties,
i.e., Seebeck coefficient, electrical resistivity, and thermal conductivity. In practical applications, due to the influence
of the harsh environment, the mechanical properties of TEMs should also be considered. Using the finite-element analysis (FEA)
model in ANSYS software, we present the thermal stress distribution of a TEM based on the anisotropic mechanical properties
and thermoelectric properties of hot-pressed materials. By analyzing the possibilities of damage along the cleavage plane
of Bi2Te3-based thermoelectric materials and by optimizing the structure parameters, a TEM with better mechanical performance is obtained.
Thus, a direction for improving the thermal stress resistance of TEMs is presented. 相似文献
5.
Boron-rich cluster compounds are studied for their potential as high-temperature thermoelectric materials with low thermal
conductivity. Two B12 icosahedra systems with attractive thermoelectric properties have recently been discovered: p-type REB44Si2 (where RE stands for rare earth) and the anomalous n-type series of RE-B-C(N) homologous compounds. Three different doping effects of these compounds were investigated in this
work in an attempt to control the properties: doping disorder into REB44Si2, which is a variable-range hopping system, V-doping of YB44Si2, and C-doping (carbon composition control) of YB28.5C4. The attempt to enhance the Seebeck coefficient in TbB44Si2 through disorder was inconclusive, while V-doping of YB44Si2 had a negative effect on the thermoelectric properties. Controlling the carbon composition of YB28.5C4 appeared to be a promising route for increasing the absolute value of the Seebeck coefficient. 相似文献
6.
Ju-Hyuk Yim Kyooho Jung Hyo-Jung Kim Hyung-Ho Park Chan Park Jin-Sang Kim 《Journal of Electronic Materials》2011,40(5):1010-1014
The solidification of alloys in the Bi2Te3-PbTe pseudobinary system at off- and near-eutectic compositions was investigated for their microstructure and thermoelectric
properties. Dendritic and lamellar structures were clearly observed due to the phase separation and the existence of a metastable
ternary phase. In this system, three phases with different compositions were observed: binary Bi2Te3, PbTe, and metastable PbBi2Te4. The Seebeck coefficient, electrical resistivity, and thermal conductivity of ternary alloys as well as binary compounds
were measured. The phonon thermal conductivities of Pb-Bi-Te alloys were lower than those in binary PbTe and Bi2Te3, which could have resulted from the increased interfacial area between phases due to the existence of the metastable ternary
phase and the resultant phase separation. 相似文献
7.
L. D. Ivanova Yu. V. Granatkina L. I. Petrova I. Yu. Nikhezina A. G. Malchev V. V. Alenkov S. A. Kichik A. A. Melnikov 《Semiconductors》2017,51(8):1002-1004
The thermoelectric properties of n-type Bi2Te2.4Se0.6 solid solution prepared by the vacuum hot pressing of powder mixtures with different particle sizes are investigated. The powders were prepared by the mechanical grinding of ingots and melt spinning. The microstructure and fracture pattern of a sample cleavage surface are analyzed using scanning electron microscopy and optical microscopy. The thermoelectric characteristics (the Seebeck coefficient, electrical conductivity, and thermal conductivity) are measured at room temperature and in the temperature range of 100–700 K. 相似文献
8.
We realized cationic substitutions in Sr2IrO4 and measured resistivity, thermoelectric power, and the Hall coefficient. A two-carrier model, reflecting the presence of
thermally activated carriers at high temperature, qualitatively explains the behavior of the Hall coefficient of Sr1.95La0.05IrO4 in comparison with Sr2IrO4. Concerning the substitution of Ir by different transition metals, Pt with 5d orbitals does not affect the transport properties, contrary to Ti and Rh with 3d and 4d orbitals, respectively. This may be explained by strong spin–orbit coupling involved in Ir and Pt, in comparison with 3d or 4d transition metals. 相似文献
9.
S. Stefanoski L. N. Reshetova A. V. Shevelkov G. S. Nolas 《Journal of Electronic Materials》2009,38(7):985-989
We report on temperature-dependent thermal conductivity, resistivity, and Seebeck coefficient of two polycrystalline Br-containing
Sn-clathrate compounds with the type I crystal structure. Interstitial Br atoms reside inside the polyhedral cavities formed
by the framework, resulting in hole conduction. The framework bonding directly influences the transport properties of these
two compositions. The transport properties of these two clathrates are compared with those of other Sn-clathrates. We also
discuss our results in terms of the potential for thermoelectric applications. 相似文献
10.
Michihiro Ohta Atsushi Yamamoto Haruhiko Obara 《Journal of Electronic Materials》2010,39(9):2117-2121
Chevrel-phase sulfides M
x
Mo6S8 (M, Cr, Mn, Fe, Ni; x: 1.3, 2.0) were prepared by reacting appropriate amounts of M, Mo, and MoS2 powders. The samples were then consolidated by pressure-assisted sintering to fabricate dense compacts. While Cr1.3Mo6S8 crystallized in a triclinic structure, Mn1.3Mo6S8, Fe1.3Mo6S8, and Ni2.0Mo6S8 crystallized in a hexagonal structure. The Seebeck coefficient, electrical resistivity, and thermal conductivity of the sintered
samples were measured over the temperature range of 300 K to 973 K. All the samples exhibited a positive Seebeck coefficient.
The Seebeck coefficient, electrical resistivity, and thermal conductivity of M1.3Mo6S8 (M: Cr, Mn, Fe) were almost identical and increased with temperature. However, the corresponding values and temperature dependent
behavior of Ni2.0Mo6S8 were different from those of M1.3Mo6S8 (M: Cr, Mn, Fe). For Ni2.0Mo6S8, as temperature increased, the Seebeck coefficient and thermal conductivity increased while the electrical resistivity decreased.
The highest value of the thermoelectric figure of merit (0.17) was observed in Cr1.3Mo6S8 at 973 K. 相似文献
11.
n-Type nanoporous Bi2Te3-based thermoelectric materials with different porosity ratios have been prepared by spark plasma sintering (SPS). The microstructure
and phase morphology have been analyzed by x-ray diffraction (XRD) and field-emission scanning electron microscopy (FESEM),
and the thermoelectric properties of the SPS samples have been measured. Experimental results show that the nanoporous structures
lying in the sheet layers and among the plate grains of the Bi2Te3 bulk material can lead to an increase in the Seebeck coefficient and a decrease in the thermal conductivity, thus leading
to an enhanced figure of merit. 相似文献
12.
Yasuhiro Toyama Hirofumi Hazama Ryoji Asahi Tsunehiro Takeuchi 《Journal of Electronic Materials》2011,40(5):1052-1056
To optimize the thermoelectric properties of Si2Ti-type Al32Mn34Si34 (C54-phase), which possesses a large absolute Seebeck coefficient |S| exceeding 300 μV/K with negative sign, we partially substituted Cr and Fe for Mn, and succeeded in decreasing the number of valence electrons
(in the case of Cr) without observing precipitation of secondary phases. A large, positive Seebeck coefficient exceeding 200 μV/K was observed for Al32Cr
x
Mn34−x
Si34 (1 ≤ x ≤ 2.5), which consists almost solely of the C54-phase. The increase of hole concentration caused by Cr substitution for Mn was confirmed by both the reduction in electrical
resistivity and the sign reversal of the Seebeck coefficient. The largest ZT-value for positive Seebeck coefficient (p-type behavior) was obtained for Al32Cr2.5Mn31.5Si34, with the resulting ZT-value reaching a magnitude twice as large as the largest ZT-value of the ternary compound Al33Mn34Si33 possessing p-type behavior. 相似文献
13.
Ternary rare-earth sulfides NdGd1+x
S3, where 0 ≤ x ≤ 0.08, were prepared by sulfurizing Ln2O3 (Ln = Nd, Gd) with CS2 gas, followed by reaction sintering. The sintered samples have full density and homogeneous compositions. The Seebeck coefficient,
electrical resistivity, and thermal conductivity were measured over the temperature range of 300 K to 950 K. All the sintered
samples exhibit a negative Seebeck coefficient. The magnitude of the Seebeck coefficient and the electrical resistivity decrease
systematically with increasing Gd content. The thermal conductivity of all the sintered samples is less than 1.9 W K−1 m−1. The highest figure of merit ZT of 0.51 was found in NdGd1.02S3 at 950 K. 相似文献
14.
In this study, we investigated the chemical composition and electronic structure of the delafossite-type oxides CuFeO2 (CFO) and CuFe0.98Ni0.02O2 (CFNO). The hole carrier density in the Cu and FeO2 layers of CFNO was found to be different from that of CFO, leading to the enhancement of electrical conductivity by Ni substitution.
In addition, thermoelectric properties were found to be affected by the surface treatment, possibly due to some surface contamination.
An etched CFNO (E-CFNO) exhibited a higher electrical conductivity and a higher Seebeck coefficient relative to the polished
CFNO (P-CFNO). The thermal conductivity did not change much between E-CFNO and P-CFNO. As a result, the thermoelectric performance
of E-CFNO was higher than that of P-CFNO. This result indicates that etching is needed when we use CFNO as a p-leg in thermoelectric generators. 相似文献
15.
A. A. Kuzanyan A. S. Kuzanyan G. R. Badalyan S. I. Petrosyan V. O. Vardanyan V. N. Gurin M. P. Volkov S. Kh. Pilosyan 《Semiconductors》2017,51(8):999-1001
Films of cerium hexaboride, a material promising for use in thermoelectric devices at liquidhelium temperatures, are produced by electron-beam deposition. Deposition is carried out from ceramic targets onto insulator, semiconductor, and metal substrates at different temperatures. The microstructure, the elemental and phase compositions, the temperature dependences of the resistivity and the Seebeck coefficient are thoroughly studied. CaB6-structured films, for which the structure is characteristic of cerium hexaboride and the elemental composition is close to the stoichiometric composition, are obtained. At low temperatures, the resistivity of the films is somewhat higher than that of single-crystal samples, and the Seebeck coefficient is close to the corresponding coefficient for single-crystal samples. The main cause of the difference between the resistance values is a high concentration of oxygen impurity detected in the films. 相似文献
16.
H. L. Gao X. X. Liu T. J. Zhu S. H. Yang X. B. Zhao 《Journal of Electronic Materials》2011,40(5):830-834
This study focuses on Sb-doped Mg2(Si,Sn) thermoelectric material. Samples were successfully fabricated using a hybrid synthesis method consisting of three
different processes: induction melting, solid-state reaction, and a hot-press sintering technique. We found that the carrier
concentration increased with Sb content, while the Seebeck coefficient exhibited a decreasing trend. Sb doping was shown to
improve the power factor and thermoelectric figure of merit compared with the undoped material, yielding a peak figure of
merit (ZT) of ~0.55 at 620 K, while leaving the band gap of Mg2Si0.7Sn0.3 almost unchanged. 相似文献
17.
Wenhao Fan Ruixue Chen Liqi Wang Peide Han Qingsen Meng 《Journal of Electronic Materials》2011,40(5):1209-1214
The thermoelectric properties of Y-doped (1000 ppm, 2000 ppm, 3000 ppm) Mg2Si fabricated using field-activated pressure-assisted synthesis (FAPAS) have been characterized using measurements of electrical
resistivity (ρ), Seebeck coefficient (S), and thermal conductivity (κ) at temperatures ranging from 285 K to 810 K. The Y-doped Mg2Si samples were n-type in the measured temperature range. A first-principles calculation revealed that the Y atoms were expected to be primarily
located at Mg sites. In sample doped with 2000 ppm Y, which exhibited the best electrical and thermal conductivity, the absolute
value of the Seebeck coefficient increased in the temperature range of 320 K to 680 K, being higher than that of undoped Mg2Si. Moreover, this sample exhibited a higher level of electrical conductivity and a higher power factor. In addition, introduction
of Y decreased the thermal conductivity appreciably, indicating that Y dopants are favorable for improving the properties
of Mg2Si. 相似文献
18.
Tong Zhou Bertrand Lenoir Candolfi Christophe Anne Dauscher Philippe Gall Patrick Gougeon Michel Potel Emmanuel Guilmeau 《Journal of Electronic Materials》2011,40(5):508-512
Thermoelectric properties of molybdenum selenides containing Mo9 clusters have been investigated between 300 K and 800 K. Ag
x
Mo9Se11 (x = 3.4 and 3.8) have been synthesized by solid-state reaction and spark plasma sintering. X-ray diffraction and scanning electron
microscopy reveal high purity and good homogeneity of the samples. The thermoelectric power of the samples is positive over
the whole investigated temperature range, indicating that the majority of charge carriers are holes. The Seebeck coefficient
increases with temperature, and the temperature coefficient of the resistivity is positive. Significantly low thermal conductivity,
comparable to values reported for state-of-the-art thermoelectric materials, is observed in this new system, and this is assumed
to be associated with the rattling effect from the Ag filler atoms. It has been demonstrated that the electrical and thermal
properties correlate to the Ag concentration. For x = 3.8, a promising dimensionless thermoelectric figure of merit of ∼0.7 is obtained at 800 K. 相似文献
19.
S. Y. Wang W. J. Xie H. Li X. F. Tang Q. J. Zhang 《Journal of Electronic Materials》2011,40(5):1150-1157
A series of Bi2(Se0.4Te0.6)3 compounds were synthesized by a rapid route of melt spinning (MS) combined with a subsequent spark plasma sintering (SPS)
process. Measurements of the Seebeck coefficient, electrical conductivity, and thermal conductivity were performed over the
temperature range from 300 K to 520 K. The measurement results showed that the cooling rate of melt spinning had a significant
impact on the transport properties of electrons and phonons, effectively enhancing the thermoelectric properties of the compounds.
The maximum ZT value reached 0.93 at 460 K for the sample prepared with the highest cooling rate, and infrared spectrum measurement results
showed that the compound with lower tellurium content, Bi2(Se0.4Te0.6)3, possesses a larger optical forbidden gap (E
g) compared with the traditional n-type zone-melted material with formula Bi2(Se0.07Te0.93)3. Our work provides a new approach to develop low-tellurium-bearing Bi2Te3-based compounds with good thermoelectric performance. 相似文献
20.
B. N. Pantha R. Dahal J. Li J. Y. Lin H. X. Jiang G. Pomrenke 《Journal of Electronic Materials》2009,38(7):1132-1135
We report on the experimental investigation of the potential of InGaN alloys as thermoelectric (TE) materials. We have grown
undoped and Si-doped In0.3Ga0.7N alloys by metalorganic chemical vapor deposition and measured the Seebeck coefficient and electrical conductivity of the
grown films with the aim of maximizing the power factor (P). It was found that P decreases as electron concentration (n) increases. The maximum value for P was found to be 7.3 × 10−4 W/m K2 at 750 K in an undoped sample with corresponding values of Seebeck coefficient and electrical conductivity of 280 μV/K and 93␣(Ω cm)−1, respectively. Further enhancement in P is expected by improving the InGaN material quality and conductivity control by reducing background electron concentration. 相似文献