Effect of Yb Filling on Thermoelectric Properties of Ge-Substituted CoSb&lt;SUB&gt;3&lt;/SUB&gt; Skutterudites

Mori, Hiroshi; Anno, Hiroaki; Matsubara, K.

doi:10.2320/matertrans.46.1476

Cited by 9 publications

(8 citation statements)

References 14 publications

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“…Assuming that

sans-serifλ = 0

for acoustic-phonon scattering which is the generally accepted dominant scattering mechanism for the conduction parabolic band [25,26], the calculated reduced Fermi level was −2.3965, which means that the Fermi level lies in the bandgap, a characteristic in non-degenerated semiconductors.…”

Section: Resultsmentioning

confidence: 99%

Effect of Native Defects on Transport Properties in Non-Stoichiometric CoSb3

et al. 2017

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The effect of native defects originated by a non-stoichiometric variation of composition in CoSb3 on I-V curves and Hall effect was investigated. Hysteretic and a non-linear behavior of the I-V curves at cryogenic temperatures were observed; the non-linear behavior originated from the Poole-Frenkel effect, a field-dependent ionization mechanism that lowers Coulomb barriers and increases emission of charge carriers, and the hysteresis was attributed to the drastic decrease of specific heat which produces Joule heating at cryogenic temperatures. CoSb3 is a narrow gap semiconductor and slight variation in the synthesis process can lead to either n- or p-type conduction. The Sb-deficient CoSb3 presented an n-type conduction. Using a single parabolic model and assuming only acoustic-phonon scattering the charge transport properties were calculated at 300 K. From this model, a carrier concentration of 1.18 × 1018 cm−3 and a Hall factor of 1.18 were calculated. The low mobility of charge carriers, 19.11 cm2/V·s, and the high effective mass of the electrons, 0.66 m0, caused a high resistivity value of 2.75 × 10−3 Ω·m. The calculated Lorenz factor was 1.50 × 10−8 V2/K2, which represents a decrease of 38% over the degenerate limit value (2.44 × 10−8 V2/K2).

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“…Assuming that

sans-serifλ = 0

Section: Resultsmentioning

confidence: 99%

Effect of Native Defects on Transport Properties in Non-Stoichiometric CoSb3

et al. 2017

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“…The effective mass was estimated by using a simple parabolic band model dominated with acoustic phonon scattering. The Seebeck coefficient S is described as below 32,43 S ¼ 6 j B e…”

Section: Thermoelectric and Transport Properties Of Yb Y Fe X Co 4mentioning

confidence: 99%

The structural, transport, and magnetic properties of Yb-filled skutterudites YbyFexCo4−xSb12 synthesized under high pressure

Chen

Kawamura

Hoshino

et al. 2016

Journal of Applied Physics

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“…These fillers can significantly strengthen the phonon scattering to reduce κ l in CoSb 3 -based skutterudites. Particularly, rare-earth Yb and Ce fillers, with heavy atomic masses and small ionic radii, can effectively reduce κ l . , For the p-type CoSb 3 -based skutterudites, the dominating carriers and the corresponding electrical conducting types can be tuned by substitution at the Co or Sb site. − Pandya et al partially replaced Co with Fe, and a p-type Co 0.95 Fe 0.05 Sb 3 was obtained with a room-temperature S of ∼55 μV K –1 and a high S 2 σ of ∼10 μW cm –1 K –2 . Ba-filled and Fe-substituted (at Co sites) BaFe 4 Sb 12 possesses a p-type electrical conducting behavior with a room-temperature S of ∼65 μV K –1 and a zT of 0.62 at 800 K. In addition, Ge substitution at the Sb site forms a p-type Co 4 Ge 0.5 Sb 11.5 with a room-temperature S of ∼50 μV K –1 .…”

Section: Introductionmentioning

confidence: 99%

Impurity Removal Leading to High-Performance CoSb₃-Based Skutterudites with Synergistic Carrier Concentration Optimization and Thermal Conductivity Reduction

Liu

et al. 2021

ACS Appl. Mater. Interfaces

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Thermoelectric properties of CoSb 3 -based skutterudites are greatly determined by the removal of detrimental impurities, such as (Fe/Co)Sb 2 , (Fe/Co)Sb, and Sb. In this study, we use a facile temperature gradient zone melting (TGZM) method to synthesize high-performance CoSb 3 -based skutterudites by impurity removal. After removing metallic or semimetallic impurities (Fe/Co)Sb, (Fe/Co)Sb 2 , and Sb, the carrier concentration of TGZM-Ce 0.75 Fe 3 CoSb 12 can be reduced to 1.21 × 10 20 cm −3 and the electronic thermal conductivity dramatically reduced to 0.7 W m −1 K −1 at 693 K. Additionally, removing these impurities also effectively reduces the lattice thermal conductivity from 7.2 W m −1 K −1 of cast-Ce 0.75 Fe 3 CoSb 12 to 1.02 W m −1 K −1 of TGZM-Ce 0.75 Fe 3 CoSb 12 at 693 K. As a consequence, TGZM-Ce 0.75 Fe 3 CoSb 12 approaches a high power factor of 11.7 μW cm −1 K −2 and low thermal conductivity of 1.72 W m −1 K −1 at 693 K, leading to a peak zT of 0.48 at 693 K, which is 10 times higher than that of cast-Ce 0.75 Fe 3 CoSb 12 . This study indicates that our facile TGZM method can effectively synthesize high-performance CoSb 3 -based skutterudites by impurity removal and set up a solid foundation for further development.

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Effect of Yb Filling on Thermoelectric Properties of Ge-Substituted CoSb<SUB>3</SUB> Skutterudites

Cited by 9 publications

References 14 publications

Effect of Native Defects on Transport Properties in Non-Stoichiometric CoSb3

Effect of Native Defects on Transport Properties in Non-Stoichiometric CoSb3

The structural, transport, and magnetic properties of Yb-filled skutterudites YbyFexCo4−xSb12 synthesized under high pressure

Impurity Removal Leading to High-Performance CoSb₃-Based Skutterudites with Synergistic Carrier Concentration Optimization and Thermal Conductivity Reduction

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Effect of Yb Filling on Thermoelectric Properties of Ge-Substituted CoSb<SUB>3</SUB> Skutterudites

Cited by 9 publications

References 14 publications

Effect of Native Defects on Transport Properties in Non-Stoichiometric CoSb3

Effect of Native Defects on Transport Properties in Non-Stoichiometric CoSb3

The structural, transport, and magnetic properties of Yb-filled skutterudites YbyFexCo4−xSb12 synthesized under high pressure

Impurity Removal Leading to High-Performance CoSb3-Based Skutterudites with Synergistic Carrier Concentration Optimization and Thermal Conductivity Reduction

Contact Info

Product

Resources

About

Impurity Removal Leading to High-Performance CoSb₃-Based Skutterudites with Synergistic Carrier Concentration Optimization and Thermal Conductivity Reduction