Abstract
Copper-based chalcogenides with tetrahedral framework structures have been attracting increasing attention as environmentally friendly thermoelectric materials. A representative group of such thermoelectric chalcogenides is the Cu 26 A 2 M 6 S 32 (A = V, Nb, Ta; M = Ge, Sn) family of colusites, which exhibit low electrical resistivity, a large Seebeck coefficient, and low thermal conductivity; these properties are necessary for efficient thermal-to-electronic energy conversion. Here, we show the impact of crystal structure on the lattice thermal conductivity of colusite with A = Nb, M = Sn. The crystal structure can be modified by controlling the cationic compositions and the deficiency in the sulfur content as Cu 26-x Nb 2 Sn 6+x S 32-δ . The Cu/Sn ratio is found to be the key parameter for exsolution into distinct phases with ordered and disordered arrangements of cations. For the ordered-structure phase, sulfur sublimation induces atomic-scale defects/disordered states including interstitial defects, anti-site defects, and site splitting, which function as strong phonon scatterers, and the lowest lattice thermal conductivity of ∼0.5 W K -1 m -1 is achieved for the modified ordered structure. This finding provides a simple approach to modifying the crystal structure of thermoelectric chalcogenides via the loss of anions to reduce their lattice thermal conductivity.
| Original language | English |
|---|---|
| Pages (from-to) | 228-235 |
| Number of pages | 8 |
| Journal | Journal of Materials Chemistry A |
| Volume | 7 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - Jan 1 2019 |
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All Science Journal Classification (ASJC) codes
- Chemistry(all)
- Renewable Energy, Sustainability and the Environment
- Materials Science(all)
Cite this
Atomic-scale phonon scatterers in thermoelectric colusites with a tetrahedral framework structure. / Suekuni, Koichiro; Shimizu, Yuta; Nishibori, Eiji; Kasai, Hidetaka; Saito, Hikaru; Yoshimoto, Daichi; Hashikuni, Katsuaki; Bouyrie, Yohan; Chetty, Raju; Ohta, Michihiro; Guilmeau, Emmanuel; Takabatake, Toshiro; Watanabe, Kosuke; Ohtaki, Michitaka.
In: Journal of Materials Chemistry A, Vol. 7, No. 1, 01.01.2019, p. 228-235.Research output: Contribution to journal › Article
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TY - JOUR
T1 - Atomic-scale phonon scatterers in thermoelectric colusites with a tetrahedral framework structure
AU - Suekuni, Koichiro
AU - Shimizu, Yuta
AU - Nishibori, Eiji
AU - Kasai, Hidetaka
AU - Saito, Hikaru
AU - Yoshimoto, Daichi
AU - Hashikuni, Katsuaki
AU - Bouyrie, Yohan
AU - Chetty, Raju
AU - Ohta, Michihiro
AU - Guilmeau, Emmanuel
AU - Takabatake, Toshiro
AU - Watanabe, Kosuke
AU - Ohtaki, Michitaka
PY - 2019/1/1
Y1 - 2019/1/1
N2 - Copper-based chalcogenides with tetrahedral framework structures have been attracting increasing attention as environmentally friendly thermoelectric materials. A representative group of such thermoelectric chalcogenides is the Cu 26 A 2 M 6 S 32 (A = V, Nb, Ta; M = Ge, Sn) family of colusites, which exhibit low electrical resistivity, a large Seebeck coefficient, and low thermal conductivity; these properties are necessary for efficient thermal-to-electronic energy conversion. Here, we show the impact of crystal structure on the lattice thermal conductivity of colusite with A = Nb, M = Sn. The crystal structure can be modified by controlling the cationic compositions and the deficiency in the sulfur content as Cu 26-x Nb 2 Sn 6+x S 32-δ . The Cu/Sn ratio is found to be the key parameter for exsolution into distinct phases with ordered and disordered arrangements of cations. For the ordered-structure phase, sulfur sublimation induces atomic-scale defects/disordered states including interstitial defects, anti-site defects, and site splitting, which function as strong phonon scatterers, and the lowest lattice thermal conductivity of ∼0.5 W K -1 m -1 is achieved for the modified ordered structure. This finding provides a simple approach to modifying the crystal structure of thermoelectric chalcogenides via the loss of anions to reduce their lattice thermal conductivity.
AB - Copper-based chalcogenides with tetrahedral framework structures have been attracting increasing attention as environmentally friendly thermoelectric materials. A representative group of such thermoelectric chalcogenides is the Cu 26 A 2 M 6 S 32 (A = V, Nb, Ta; M = Ge, Sn) family of colusites, which exhibit low electrical resistivity, a large Seebeck coefficient, and low thermal conductivity; these properties are necessary for efficient thermal-to-electronic energy conversion. Here, we show the impact of crystal structure on the lattice thermal conductivity of colusite with A = Nb, M = Sn. The crystal structure can be modified by controlling the cationic compositions and the deficiency in the sulfur content as Cu 26-x Nb 2 Sn 6+x S 32-δ . The Cu/Sn ratio is found to be the key parameter for exsolution into distinct phases with ordered and disordered arrangements of cations. For the ordered-structure phase, sulfur sublimation induces atomic-scale defects/disordered states including interstitial defects, anti-site defects, and site splitting, which function as strong phonon scatterers, and the lowest lattice thermal conductivity of ∼0.5 W K -1 m -1 is achieved for the modified ordered structure. This finding provides a simple approach to modifying the crystal structure of thermoelectric chalcogenides via the loss of anions to reduce their lattice thermal conductivity.
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U2 - 10.1039/c8ta08248k
DO - 10.1039/c8ta08248k
M3 - Article
VL - 7
SP - 228
EP - 235
JO - Journal of Materials Chemistry A
JF - Journal of Materials Chemistry A
SN - 2050-7488
IS - 1
ER -