Composition optimization of p-type skutterudites CeyFexCo4−xSb12 and YbyFexCo4−xSb12

Liu, Ruiheng; Qiu, Pengfei; Chen, Xihong; Huang, Xiangyang; Chen, Lidong

doi:10.1557/jmr.2011.85

Cited by 42 publications

(18 citation statements)

References 36 publications

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“…In the case of heavily doped semiconductors, the mobility ratio however is no longer a valid guide for understanding or predicting κ b , due to the substantially different majority and minority carrier concentrations. For example, recent experiments showed significant κ b in p -ty p e heavily-doped skutterudites despite of the mobility ratio between two carriers being greater than 10 (hole mobility ~1–5 cm 2 /V-s with a concentration of ~10 21 cm −3 and electron mobility ~30–50 cm 2 /V-s with a concentration of ~10 18 –10 19 cm −3 at 800 K, according to our numerical analyses which are presented below)1415161718, while the n-type skutterudites do not show appreciable κ b , consistent with the rather small b value (~1/50)1920212223242526272829. Similar observations have been reported for many other semiconductors30313233343536373839.…”

supporting

confidence: 64%

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Conductivity-limiting bipolar thermal conductivity in semiconductors

Wang

Yang

Toll

et al. 2015

Sci Rep

119

101

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Intriguing experimental results raised the question about the fundamental mechanisms governing the electron-hole coupling induced bipolar thermal conduction in semiconductors. Our combined theoretical analysis and experimental measurements show that in semiconductors bipolar thermal transport is in general a “conductivity-limiting” phenomenon, and it is thus controlled by the carrier mobility ratio and by the minority carrier partial electrical conductivity for the intrinsic and extrinsic cases, respectively. Our numerical method quantifies the role of electronic band structure and carrier scattering mechanisms. We have successfully demonstrated bipolar thermal conductivity reduction in doped semiconductors via electronic band structure modulation and/or preferential minority carrier scatterings. We expect this study to be beneficial to the current interests in optimizing thermoelectric properties of narrow gap semiconductors.

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confidence: 64%

“…2, where R represents fillers and x the filling fraction. The data were taken from the literatures141516171819202122232425262747484950515253545556575859 and were well represented by an empirical expression (the solid lines in fig. 2)60…”

Section: Resultsmentioning

confidence: 99%

Conductivity-limiting bipolar thermal conductivity in semiconductors

Wang

Yang

Toll

et al. 2015

Sci Rep

119

101

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“…It is noted the thermoelectric performance of our HPS Ce y Fe 4− x Co x Sb 12 samples deteriorates with increasing Co substitution level, which differs from those ambient-pressure synthesized samples. For example, the highest ZT of 0.9 was achieved in Ce 0.9 Fe 3 CoSb 12 [21] and CeFe 3.8 Co 0.2 Sb 12 [22]. In our samples, the actual filling fraction of Ce only slightly decreases with increasing Co content, which leads to a much smaller hole concentration and an undesirable increase in ρ compared with those ambient-pressure synthesized samples.…”

Section: Resultsmentioning

confidence: 74%

“…The hole concentration deduced from the measured Hall coefficient decreases notably with elevating Co substitution level, which is due to Co substitution introducing extra electrons into the system. In addition, the hole concentration in our Ce 0.85 Fe 3.03 Co 0.97 Sb 12 sample is 9.5 × 10 20 cm −3 , less than half of that in the ambient-pressure synthesized Ce 0.9 Fe 3 CoSb 12 (nominal composition) [21]. The difference can be attributed to the higher filling fraction of Ce in our HPS sample, and accounts for the significant increase in the electrical resistivity of our HPS Ce 0.85 Fe 3.03 Co 0.97 Sb 12 sample.…”

Section: Resultsmentioning

confidence: 96%

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High Pressure Synthesis of p-Type CeyFe4−xCoxSb12 Skutterudites

Liu

Zhang

et al. 2016

Materials

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Co-substituted p-Type CeFe4−xCoxSb12 skutterudites were successfully synthesized with a high pressure synthesis method. The structure, composition, and thermoelectric properties were investigated. The obtained CeyFe4−xCoxSb12 samples show the skutterudite structure of Imtrue3¯ symmetry. The hole concentration decreases with elevating Co substitution level, leading to increased Seebeck coefficient and electrical resistivity. Meanwhile, the filling fraction of Ce decreases, which is unfavorable for reducing the lattice thermal conductivity. As a result, the thermoelectric performance of CeyFe4−xCoxSb12 deteriorates with higher Co content. The maximal ZT of 0.91 was achieved at 763 K for the optimal Ce0.92Fe4Sb12 sample.

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Upscaled Synthesis of n‐ and p‐Type Thermoelectric Skutterudite Single Legs by Gas Atomization and Current‐Assisted Sintering

Stiewe

Sottong

Boor

et al. 2018

Physica Status Solidi (a)

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CoSb 3 -based Skutterudites are among the best materials for thermoelectric generator (TEG) applications in the intermediate temperature range up to 500 C. Synthesis of these materials is usually performed on a laboratory scale in materials research. In order to be suitable for an industrial low cost production of TEG technologies capable of delivering large amounts of thermoelectric (TE) materials are needed. A process mastering this challenge is gas atomization, which has been adapted to the requirements of TE materials, in particular CoSb 3 -based Skutterudites. It is found that despite rapid solidification taking place in the atomization process the produced powder material contains only traces of the target Skutterudite phase. Microstructure investigation shows a very fine dispersion on the micrometer scale of CoSb, CoSb 2 , and Sb phases in the atomized particles, making diffusion paths for the formation of the Skutterudite phase short. This allows the use of short-term heat treatment to achieve almost single phase material of high functional homogeneity. Different thermal post-treatments are evaluated leading to a content of >98% of the Skutterudite phase in large ingots. Doping and filling by varying the starting composition is applied to tune the materials to n-and p-type conduction, respectively, and led to an increase of their thermoelectric figure of merit ZT up to values of 0.9 and 0.72 for n-and p-type material, respectively.

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Composition optimization of p-type skutterudites Ce_yFe_xCo_4−xSb₁₂ and Yb_yFe_xCo_4−xSb₁₂

Abstract: Abstract

Cited by 42 publications

References 36 publications

Conductivity-limiting bipolar thermal conductivity in semiconductors

Conductivity-limiting bipolar thermal conductivity in semiconductors

High Pressure Synthesis of p-Type CeyFe4−xCoxSb12 Skutterudites

Upscaled Synthesis of n‐ and p‐Type Thermoelectric Skutterudite Single Legs by Gas Atomization and Current‐Assisted Sintering

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