| Project/Area Number |
11555236
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| Research Category |
Grant-in-Aid for Scientific Research (B).
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
無機工業化学
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| Research Institution | Nagoya University |
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Principal Investigator |
KOUMOTO Kunihiro School of Engineering, Nagoya University, Professor, 大学院・工学研究科, 教授 (30133094)
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| Co-Investigator(Kenkyū-buntansha) |
SEO Wonseon School of Engineering, Nagoya University, Associate Professor, 大学院・工学研究科, 助教授 (30242829)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥7,900,000 (Direct Cost: ¥7,900,000)
Fiscal Year 2000: ¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 1999: ¥4,400,000 (Direct Cost: ¥4,400,000)
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| Keywords | (ZnO)_m In_2O_3 / Rietreld analysis / homologous compounds / thermoelectric conversion / Seebeck coefficient / crystal structure / thermoelectric efficiency / (ZnO)_mIn_2O_3 / Zinc oxide / Indium oxide / Homologous / Thermoelectric / Electron mobility / Substitution / Riedveld analysis / Figure of merit |
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| Research Abstract |
We have proposed that homologous compounds of (ZnO)_mIn_2O_3 with layer structures can become candidate materials for high-temperature thermoelectric conversion due to their low thermal conductivity and high electron mobility. Crystal structures can be modified by the isoelectronic substitution of either divalent or trivalent metal ions for Zn or In ions, respectively. The substitution of Mg^<2+>, Co^<2+> and Y^<3+> gave rise to the shrinkage of c-axis and the elongation of a-axis of a hexagonal unit cell. Rietveld structure refinement indicated that Mg^<2+> and Co^<2+> ions occupy both 3a and 6c sites, while Y^<3+> occupy only 3a sites. An optimum amount of substitution of these cations increased electron mobility and hence the thermoelectric efficiency Z=σα^2/κ (σ-electrical conductivity, α-Seebeck coefficient, κ-thermal conductivity). Z values coupled with lowered thermal conductivity, which was possibly caused by stable modification of the electronic structure associated with distortion of the crystal structure.
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