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1.
Kwan-Ho Park Jae-Yong Jung Soon-Chul Ur Il-Ho Kim 《Journal of Electronic Materials》2010,39(9):1750-1754
The thermoelectric properties of In-filled and Fe-doped CoSb3 (In
z
Co4−x
- Fe
x
Sb12) skutterudites prepared by encapsulated induction melting were examined. A single δ-phase was obtained successfully by subsequent
annealing at 823 K for 120 h. The Hall and Seebeck coefficients of the In
z
Co4−x
Fe
x
Sb12 samples had positive signs, indicating p-type conduction. The electrical conductivity was increased by Fe doping, and the thermal conductivity was decreased by In
filling due to phonon scattering. The thermoelectric properties were improved by In filling and Fe doping, and were closely
related to the optimum carrier concentration and phonon scattering. 相似文献
2.
L. P. Bulat I. A. Drabkin V. V. Karatayev V. B. Osvenskii Yu. N. Parkhomenko M. G. Lavrentev A. I. Sorokin D. A. Pshenai-Severin V. D. Blank G. I. Pivovarov V. T. Bublik N. Yu. Tabachkova 《Journal of Electronic Materials》2013,42(7):2110-2113
Ball milling with subsequent spark plasma sintering (SPS) was used to fabricate bulk nanothermoelectrics based on Bi x Sb2?x Te3. The SPS technique enables reduced size of grains in comparison with the hot-pressing method. The electrical and thermal conductivities, Seebeck coefficient, and thermoelectric figure of merit as functions of temperature and alloy composition were measured for different sintering temperatures. The greatest value of the figure of merit ZT = 1.25 was reached at the temperature of 90°C to 100°C in Bi0.4Sb1.6Te3 for sintering temperature of 450°C to 500°C. The volume and quantitative distributions of size of coherent dispersion areas (CDA) were calculated for different sintering temperatures. The phonon thermal conductivity of nanostructured Bi x Sb2?x Te3 was investigated theoretically taking into account phonon scattering on grain boundaries and nanoprecipitates. 相似文献
3.
In (Bi1.9Sb0.1)1 − x
Sn
x
Te3 solid solution with different contents of Sn, the electrical conductivity (σ11) and the Hall (R
123 and R
321), Seebeck (S
11 and S
33), and Nernst-Ettingshausen (Q
123 and Q
321) coefficients have been measured. It is shown that doping with tin strongly modifies temperature dependences of the kinetic
coefficients. The effect of tin on electrical homogeneity of the samples has been studied: with increasing number of Sn atoms
embedded, crystals become more homogeneous. These features indicate the presence of the quasi-local states of Sn in the valence
band of Bi1.9Sb0.1Te3. Within a one-band model, we estimated the effective mass of the density of hole states (m
d
), the energy gap extrapolated to 0 K (E
g0 = 0.20–0.25 eV), the energy of impurity states (E
Sn ≈ 40–45 meV), and the scattering parameter (r ≈ 0.1–0.4). Numerical values of the scattering parameter indicate a mixed mechanism of scattering in the samples under investigation
with dominant scattering at acoustic phonons. With increasing content of tin in the samples, the contribution of impurity
scattering increases. 相似文献
4.
Bi
x
Sb2−x
Te3 bulk alloys are known as the best p-type thermoelectric materials near room temperature. In this work, single-phase Bi
x
Sb2−x
Te3 (x = 0.2, 0.25, 0.3, 0.34, 0.38, 0.42, 0.46, and 0.5) alloys were prepared by spark plasma sintering (SPS) using mechanical
alloying (MA)-derived powders. A small amount (0.1 vol.%) of SiC nanoparticles was added to improve the mechanical properties
and to reduce the thermal conductivity of the alloys. The electrical resistivity decreases significantly with increasing ratio
of Sb to Bi in spite of the weaker decreasing trend in Seebeck coefficient, whereby the power factor at 323 K reaches 3.14 × 10−3 W/mK2 for a sample with x = 0.3, obviously higher than that at x = 0.5 (2.27 × 10−3 W/mK2), a composition commonly used for ingots. Higher thermal conductivities at low temperatures are obtained at the compositions
with lower x values, but they tend to decrease with temperature. As a result, higher ZT values are obtained for Bi0.3Sb1.7Te3, with a maximum ZT value of 1.23 at 423 K, about twice the ZT value (about 0.6) of Bi0.5Sb1.5Te3 at the same temperature. 相似文献
5.
Hwijong Lee Yuanyuan Zhou Sungyeb Jung Hongze Li Zhe Cheng Jiaming He Jie Chen Peter Sokalski Andrei Dolocan Raluca Gearba-Dolocan Kevin C. Matthews Feliciano Giustino Jianshi Zhou Li Shi 《Advanced functional materials》2023,33(17):2212957
The lattice thermal conductivity (κph) of metals and semimetals is limited by phonon-phonon scattering at high temperatures and by electron-phonon scattering at low temperatures or in some systems with weak phonon-phonon scattering. Following the demonstration of a phonon band engineering approach to achieve an unusually high κph in semiconducting cubic-boron arsenide (c-BAs), recent theories have predicted ultrahigh κph of the semimetal tantalum nitride in the θ-phase (θ-TaN) with hexagonal tungsten carbide (WC) structure due to the combination of a small electron density of states near the Fermi level and a large phonon band gap, which suppress electron-phonon and three-phonon scattering, respectively. Here, measurements on the thermal and electrical transport properties of polycrystalline θ-TaN converted from the ε phase via high-pressure synthesis are reported. The measured thermal conductivity of the θ-TaN samples shows weak temperature dependence above 200 K and reaches up to 90 Wm−1K−1, one order of magnitude higher than values reported for polycrystalline ε-TaN and δ-TaN thin films. These results agree with theoretical calculations that account for phonon scattering by 100 nm-level grains and suggest κph increase above the 249 Wm−1 K−1 value predicted for single-crystal WC when the grain size of θ-TaN is increased above 400 nm. 相似文献
6.
Mikio Koyano Daichi Kito Kengo Sakai Tomoki Ariga 《Journal of Electronic Materials》2011,40(5):1078-1082
Application of a magnetic field greatly enhances the thermoelectric efficiency of bismuth-antimony (Bi-Sb) alloys. We synthesized
a hybrid of Bi-Sb alloy and magnetic nanoparticles, expecting improvement of the thermoelectric performance due to the magnetic
field generated by the nanoparticles. Powder x-ray diffraction and magnetic measurements of the synthesized hybrid Bi0.88Sb0.12(FeSb)0.05 sample indicated that the ferromagnetic FeSb nanoparticles, with a size of about 30 nm, were distributed in the main phase
of the Bi-Sb alloy. The FeSb nanoparticles act as soft ferromagnets in the diamagnetic host Bi-Sb alloy. The electrical resistivity
ρ of the host Bi0.88Sb0.12 sample decreased concomitantly with decreasing temperature, showing a shoulder at 80 K. In contrast, ρ for the hybrid sample was enhanced below 100 K because of carrier scattering by the nanoparticles. The temperature dependence
of the Seebeck coefficient S was also altered by the nanoparticle addition. In contrast, the addition of magnetic nanoparticles only slightly influenced
the thermal conductivity κ. These results indicate that the addition of magnetic nanoparticles to thermoelectric materials modulates the electronic
structures but does not influence the lattice system. 相似文献
7.
Indium-filled skutterudites are promising power generation thermoelectric materials due to the presence of an InSb nanostructure
that lowers the thermal conductivity. In this work, we have investigated thermoelectric properties of triple-filled Ba
x
Yb
y
In
z
Co4Sb12 (0 ≤ x, y, z ≤ 0.14 actual) compounds by measuring their Seebeck coefficient, electrical conductivity, thermal conductivity, and Hall
coefficient. All samples were prepared by a melting–annealing–spark plasma sintering method, and their structure was characterized
by x-ray diffraction and transmission electron microscopy (TEM). TEM results show the development of an InSb nanostructure
with a grain size of 30 nm to 500 nm. The nanostructure is present in all samples containing In and is also detected by specific
heat measurements. The Seebeck and Hall coefficients indicate that the compounds are n-type semiconductors. Electrical conductivity increases with increasing Ba content. Thermal conductivity is strongly suppressed
upon the presence of In in the skutterudite structure, likely due to enhanced boundary scattering of phonons on the nanometer-scale
InSb inclusions. The highest thermoelectric figure of merit is achieved with Ba0.09Yb0.07In0.06Co4Sb11.97, reaching ZT = 1.25 at 800 K. 相似文献
8.
Nanocrystalline Bi0.85Sb0.15 powders were prepared by a novel mechanical alloying method. The bulk samples were formed by applying a pressure of 6 GPa
at different pressing temperatures and times. Electrical conductivity, Seebeck coefficients, and thermal conductivity were
measured in the temperature range 80–300 K. The Seebeck coefficient reaches a maximum value of −173 μV/K at 150 K. The largest
figure of merit, 3.46 × 10−3 K−1, achieved in this experiment is 50% higher than that of its single-crystal counterpart at 200 K. 相似文献
9.
L. V. Prokofieva D. A. Pshenay-Severin P. P. Konstantinov A. A. Shabaldin 《Semiconductors》2009,43(8):973-976
The reliability of determination of model parameters for the Bi2Te3 − x
Se
x
alloys is improved by extending the concentration and temperature ranges in experimental studies and, correspondingly, in
calculations of kinetic coefficients based on the two-band model of the electronic spectrum. The obtained results served as
a motivation for a study of the thermoelectric figure of merit for the above-mentioned alloys with x = 0.3, 0.45, and 0.6 and with the electron concentration varied in the range (1–50) × 1018 cm−3 at temperatures 300–550 K. Comparison of the results showed that the highest efficiency is exhibited by the Bi2Te2.7Se0.3 alloy with the absolute value of the thermoelectric power of about 165 μVK−1 at 300 K, and the dimensionless efficiency is equal to 1.2 at 410 K. An appreciable decrease in thermal conductivity in alloys
with x = 0.6 at 410 K is related to a larger band gap and could beneficially affect the figure of merit. However, the magnitude
of this effect is found to be too small to compensate a decrease in electrical conductivity due to a large fraction of heavy
electrons in the concentration and to a high content of selenium.
Original Russian Text ? L.V. Prokofieva, D.A. Pshenay-Severin, P.P. Konstantinov, A.A. Shabaldin, 2009, published in Fizika
i Tekhnika Poluprovodnikov, 2009, Vol. 43, No. 8, pp. 1009–1012. 相似文献
10.
Fan Zhang Chen Chen Honghao Yao Fengxian Bai Li Yin Xiaofang Li Shan Li Wenhua Xue Yumei Wang Feng Cao Xingjun Liu Jiehe Sui Qian Zhang 《Advanced functional materials》2020,30(5)
Se‐doped Mg3.2Sb1.5Bi0.5‐based thermoelectric materials are revisited in this study. An increased ZT value ≈ 1.4 at about 723 K is obtained in Mg3.2Sb1.5Bi0.49Se0.01 with optimized carrier concentration ≈ 1.9 × 1019 cm?3. Based on this composition, Co and Mn are incorporated for the manipulation of the carrier scattering mechanism, which are beneficial to the dramatically enhanced electrical conductivity and power factor around room temperature range. Combined with the lowered lattice thermal conductivity due to the introduction of effective phonon scattering centers in Se&Mn‐codoped sample, a highest room temperature ZT value ≈ 0.63 and a peak ZT value ≈ 1.70 at 623 K are achieved for Mg3.15Mn0.05Sb1.5Bi0.49Se0.01, leading to a high average ZT ≈ 1.33 from 323 to 673 K. In particular, a remarkable average ZT ≈ 1.18 between the temperature of 323 and 523 K is achieved, suggesting the competitive substitution for the commercialized n‐type Bi2Te3‐based thermoelectric materials. 相似文献
11.
The electrochemical behavior of nonaqueous dimethyl sulfoxide solutions of BiIII, TeIV, and SbIII was investigated using cyclic voltammetry. On this basis, Bi
x
Sb2−x
Te
y
thermoelectric films were prepared by the potentiodynamic electrodeposition technique in nonaqueous dimethyl sulfoxide solution,
and the composition, structure, morphology, and thermoelectric properties of the films were analyzed. Bi
x
Sb2−x
Te
y
thermoelectric films prepared under different potential ranges all possessed a smooth morphology. After annealing treatment
at 200°C under N2 protection for 4 h, all deposited films showed p-type semiconductor properties, and their resistances all decreased to 0.04 Ω to 0.05 Ω. The Bi0.49Sb1.53Te2.98 thermoelectric film, which most closely approaches the stoichiometry of Bi0.5Sb1.5Te3, possessed the highest Seebeck coefficient (85 μV/K) and can be obtained under potentials of −200 mV to −400 mV. 相似文献
12.
C. Drasar A. Hovorkova P. Lostak S. Ballikaya C.-P. Li C. Uher 《Journal of Electronic Materials》2010,39(9):1760-1763
We have shown previously that indium doping is beneficial for thermoelectric properties of (Sb0.75Bi0.25)2Te3. This effect was ascribed to a change in the magnitude and mechanism of hole scattering and a decrease in thermal conductivity.
Since the state-of-the-art material for p-type legs in low-temperature applications is the quaternary Bi0.5Sb1.5Te3−y
Se
y
, we have attempted to dope this material with In, hoping to improve its properties further. Indeed, the doping enhances the
figure of merit of (Sb0.75Bi0.25)2−x
In
x
Te2.8Se0.2 by more than 15% compared with the values measured on undoped (Sb0.75Bi0.25)2Te2.8Se0.2 below room temperature. 相似文献
13.
Chia-Jyi Liu Gao-Jhih Liu Chun-Wei Tsao Yo-Jhih Huang 《Journal of Electronic Materials》2009,38(7):1499-1503
We report on the successful hydrothermal synthesis of Bi0.5Sb1.5Te3, using water as the solvent. The products of the hydrothermally prepared Bi0.5 Sb1.5Te3 were hexagonal platelets with edges of 200–1500 nm and thicknesses of 30–50 nm. Both the Seebeck coefficient and electrical
conductivity of the hydrothermally prepared Bi0.5Sb1.5Te3 were larger than those of the solvothermally prepared counterpart. Hall measurements of Bi0.5Sb1.5Te3 at room temperature indicated that the charge carrier was p-type, with a carrier concentration of 9.47 × 1018 cm−3 and 1.42 × 1019 cm−3 for the hydrothermally prepared Bi0.5Sb1.5Te3 and solvothermally prepared sample, respectively. The thermoelectric power factor at 290 K was 10.4 μW/cm K2 and 2.9 μW/cm K2 for the hydrothermally prepared Bi0.5Sb1.5Te3 and solvothermally prepared sample, respectively. 相似文献
14.
Ca
z
Co4−x
(Fe/Mn)
x
Sb12 skutterudites were prepared by mechanical alloying and hot pressing. The phases of mechanically alloyed powders were identified
as γ-CoSb2 and Sb, but they were transformed to δ-CoSb3 by annealing at 873 K for 100 h. All specimens had a positive Hall coefficient and Seebeck coefficient, indicating p-type conduction by holes as majority carriers. For the binary CoSb3, the electrical conductivity behaved like a nondegenerate semiconductor, but Ca-filled and Fe/Mn-doped CoSb3 showed a temperature dependence of a degenerate semiconductor. While the Seebeck coefficient of intrinsic CoSb3 increased with temperature and reached a maximum at 623 K, the Seebeck coefficient increased with increasing temperature
for the Ca-filled and Fe/Mn-doped specimens. Relatively low thermal conductivity was obtained because fine particles prepared
by mechanical alloying lead to phonon scattering. The thermal conductivity was reduced by Ca filling and Fe/Mn doping. The
electronic thermal conductivity was increased by Fe/Mn doping, but the lattice thermal conductivity was decreased by Ca filling.
Reasonable thermoelectric figure-of-merit values were obtained for Ca-filled Co-rich p-type skutterudites. 相似文献
15.
Wei Liu Qiang Zhang Xinfeng Tang Han Li Jeff Sharp 《Journal of Electronic Materials》2011,40(5):1062-1066
Mg2(Si0.3Sn0.7)1−y
Sb
y
(0 ≤ y ≤ 0.04) solid solutions were prepared by a two-step solid-state reaction method combined with the spark plasma sintering
technique. Investigations indicate that the Sb doping amount has a significant impact on the thermoelectric properties of
Mg2(Si0.3Sn0.7)1−y
Sb
y
compounds. As the Sb fraction y increases, the electron concentration and electrical conductivity of Mg2(Si0.3Sn0.7)1−y
Sb
y
first increase and then decrease, and both reach their highest value at y = 0.025. The sample with y = 0.025, possessing the highest electrical conductivity and one of the higher Seebeck coefficient values among all the samples,
has the highest power factor, being 3.45 mW m−1 K−2 to 3.69 mW m−1 K−2 in the temperature range of 300 K to 660 K. Meanwhile, Sb doping can significantly reduce the lattice thermal conductivity
(κ
ph) of Mg2(Si0.3Sn0.7)1−y
Sb
y
due to increased point defect scattering, and κ
ph for Sb-doped samples is 10% to 20% lower than that of the nondoped sample for 300 K < T < 400 K. Mg2(Si0.3Sn0.7)0.975Sb0.025 possesses the highest power factor and one of the lower κ
ph values among all the samples, and reaches the highest ZT value: 1.0 at 640 K. 相似文献
16.
Kyu-Hyoung Lee Hyun-Sik Kim Sang-Il Kim Eun-Sung Lee Sang-Mock Lee Jong-Soo Rhyee Jae-Yong Jung Il-Ho Kim Yifeng Wang Kunihito Koumoto 《Journal of Electronic Materials》2012,41(6):1165-1169
Introducing nanoinclusions in thermoelectric (TE) materials is expected to lower the lattice thermal conductivity by intensifying the phonon scattering effect, thus enhancing their TE figure of merit ZT. We report a novel method of fabricating Bi0.5Sb1.5Te3 nanocomposite with nanoscale metal particles by using metal acetate precursor, which is low cost and facile to scale up for mass production. Ag and Cu particles of ??40?nm were successfully near-monodispersed at grain boundaries of Bi0.5Sb1.5Te3 matrix. The well-dispersed metal nanoparticles reduce the lattice thermal conductivity extensively, while enhancing the power factor. Consequently, ZT was enhanced by more than 25% near room temperature and by more than 300% at 520?K compared with a Bi0.5Sb1.5Te3 reference sample. The peak ZT of 1.35 was achieved at 400?K for 0.1?wt.% Cu-decorated Bi0.5Sb1.5Te3. 相似文献
17.
Jianhui Li Qing Tan Jing‐Feng Li Da‐Wei Liu Fu Li Zong‐Yue Li Minmin Zou Ke Wang 《Advanced functional materials》2013,23(35):4317-4323
Thermoelectric materials have potential applications in energy harvesting and electronic cooling devices, and bismuth antimony telluride (BiSbTe) alloys are the state‐of‐the‐art thermoelectric materials that have been widely used for several decades. It is demonstrated that mixing SiC nanoparticles into the BiSbTe matrix effectively enhances its thermoelectric properties; a high dimensionless figure of merit (ZT) value of up to 1.33 at 373 K is obtained in Bi0.3Sb1.7Te3 incorporated with only 0.4 vol% SiC nanoparticles. SiC nanoinclusions possessing coherent interfaces with the Bi0.3Sb1.7Te3 matrix can increase the Seebeck coefficient while increasing the electrical conductivity, in addition to its effect of reducing lattice thermal conductivity by enhancing phonon scattering. Nano‐SiC dispersion further endows the BiSbTe alloys with better mechanical properties, which are favorable for practical applications and device fabrication. 相似文献
18.
Fan Yang Xi An Fan Zhen Zhou Rong Xin Zhi Cai Guang Qiang Li 《Journal of Electronic Materials》2014,43(11):4327-4334
The p-type Bi0.4Sb1.6Te3 alloys are prepared using a new method of mechanical alloying followed by microwave-activated hot pressing (MAHP). The effect of sintering temperature on the microstructure and thermoelectric properties of Bi0.4Sb1.6Te3 alloys is investigated. Compared with other sintering techniques, the MAHP process can be used to produce relatively compact bulk materials at lower sintering temperatures owing to its unique sintering mechanism. The grain size of the MAHP specimens increases gradually with the sintering temperature and a partially oriented lamellar structure can be formed in some regions of specimens obtained. The formation of the in situ-generated nano-phase is induced by the arcing effect of the MAHP process, which enhances the phonon scattering effect and decreases the lattice thermal conductivity. A minimum lattice thermal conductivity of 0.41 W/(m·K) and a maximum figure of merit value of 1.04 are obtained at 100°C for the MAHP specimen sintered at 325°C. This technique may also be extended to other functional materials to obtain ultrafine microstructures at low sintering temperatures. 相似文献
19.
Takashi Hamachiyo Maki Ashida Kazuhiro Hasezaki 《Journal of Electronic Materials》2009,38(7):1048-1051
A fine measurement system for measuring thermal conductivity was constructed. An accuracy of 1% was determined for the reference
quartz with a value of 1.411 W/m K. Bi0.5Sb1.5Te3 samples were prepared by mechanical alloying followed by hot-pressing. Grain sizes were varied in the range from 1 μm to 10 μm by controlling the sintering temperature in the temperature range from 623 K to 773 K. The thermal conductivity was 0.89 W/m K
for the sample sintered at 623 K, while a grain size of 1.75 μm was measured by optical microscopy and scanning electron microscopy. The thermal conductivity increased on the sample sintered
at 673 K because of grain growth and decreased on those sintered at the temperatures from 673 K to 773 K because the increase
of pore size caused to decrease thermal conductivity. The increase of thermal conductivity for the samples sintered at temperatures
above 773 K was affected by the increase of carrier concentration. 相似文献
20.
G. D. Tang Z. H. Wang X. N. Xu Y. He L. Qiu Y. W. Du 《Journal of Electronic Materials》2011,40(5):611-614
The thermoelectric properties of indium (In) and lutetium (Lu) double-filled skutterudites In
x
Lu
y
Co4Sb12 prepared by high-pressure synthesis were investigated in detail from 4 K to 365 K. Our results indicate that In and Lu double
filling can remarkably reduce the thermal conductivity, and substantially improve the thermoelectric performance. A thermoelectric
figure of merit of ZT = 0.27 for In0.13Lu0.05Co4.02Sb12 was achieved at 365 K, being larger by one order of magnitude than that for CoSb3. It is thought that the large difference in resonance frequencies of the In and Lu elements broadens the range of normal
phonon scattering in the multifilled skutterudites, helping to achieve an even lower lattice thermal conductivity. This investigation
suggests that an effective way to improve the thermoelectric performance of skutterudite materials is to use In and Lu double
filling. 相似文献