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Title: Thermoelectric Properties of Co 1-x Rh x Si 0.98B 0.02 Alloys

Abstract

In our previous study, modest boron segregation at CoSi grain boundaries could drastically reduce the electrical resistivity while maintaining a large Seebeck coefficient. We attribute this behavior to a healing effect of B on microcracks without affecting the electronic structures. CoSi 0.98B 0.02 is the optimized sample possessing the highest power factor of 60 μW K -2 cm -1 at room temperature. To reduce the thermal conductivity while maintaining the high power factor, isoelectronic substitution, i.e., Rh on Co site, is adopted. Co 1-xRh xSi 0.98B 0.02 alloys with x = 0.00, 0.05, 0.10, and 0.20 were prepared by an arc melting and annealing procedure. The lattice thermal conductivity decreases monotonically with increasing x, which is ascribed to enhanced phonon scattering by point defects. The lowest lattice thermal conductivity obtained for the x = 0.20 sample is less than 50% of that for CoSi at room temperature. However, all the samples still exhibit very low resistivity and large Seebeck coefficient and thus the power factor is not decreased much. The best sample is x = 0.10, showing a room-temperature power factor of 58 μW K -2 cm -1. The room-temperature ZT is raised by a factor of 2.3 compared withmore » CoSi due to the power factor enhancement and simultaneous thermal conductivity reduction.« less

Authors:
;
Publication Date:
Research Org.:
Energy Frontier Research Centers (EFRC) (United States). Revolutionary Materials for Solid State Energy Conversion (RMSSEC)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1381197
DOE Contract Number:  
SC0001054
Resource Type:
Journal Article
Journal Name:
Journal of Electronic Materials
Additional Journal Information:
Journal Volume: 41; Journal Issue: 6; Related Information: RMSSEC partners with Michigan State University (lead); University of California, Los Angeles; University of Michigan; Northwestern University; Oak Ridge National Laboratory; Ohio State University; Wayne State University; Journal ID: ISSN 0361-5235
Publisher:
Springer
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; solar (thermal), phonons, thermal conductivity, thermoelectric, mechanical behavior, charge transport, materials and chemistry by design, synthesis (novel materials), synthesis (self-assembly), synthesis (scalable processing)

Citation Formats

Sun, Hui, and Morelli, Donald T. Thermoelectric Properties of Co1-x Rh x Si0.98B0.02 Alloys. United States: N. p., 2012. Web. doi:10.1007/s11664-011-1883-7.
Sun, Hui, & Morelli, Donald T. Thermoelectric Properties of Co1-x Rh x Si0.98B0.02 Alloys. United States. doi:10.1007/s11664-011-1883-7.
Sun, Hui, and Morelli, Donald T. Wed . "Thermoelectric Properties of Co1-x Rh x Si0.98B0.02 Alloys". United States. doi:10.1007/s11664-011-1883-7.
@article{osti_1381197,
title = {Thermoelectric Properties of Co1-x Rh x Si0.98B0.02 Alloys},
author = {Sun, Hui and Morelli, Donald T.},
abstractNote = {In our previous study, modest boron segregation at CoSi grain boundaries could drastically reduce the electrical resistivity while maintaining a large Seebeck coefficient. We attribute this behavior to a healing effect of B on microcracks without affecting the electronic structures. CoSi0.98B0.02 is the optimized sample possessing the highest power factor of 60 μW K-2 cm-1 at room temperature. To reduce the thermal conductivity while maintaining the high power factor, isoelectronic substitution, i.e., Rh on Co site, is adopted. Co1-xRhxSi0.98B0.02 alloys with x = 0.00, 0.05, 0.10, and 0.20 were prepared by an arc melting and annealing procedure. The lattice thermal conductivity decreases monotonically with increasing x, which is ascribed to enhanced phonon scattering by point defects. The lowest lattice thermal conductivity obtained for the x = 0.20 sample is less than 50% of that for CoSi at room temperature. However, all the samples still exhibit very low resistivity and large Seebeck coefficient and thus the power factor is not decreased much. The best sample is x = 0.10, showing a room-temperature power factor of 58 μW K-2 cm-1. The room-temperature ZT is raised by a factor of 2.3 compared with CoSi due to the power factor enhancement and simultaneous thermal conductivity reduction.},
doi = {10.1007/s11664-011-1883-7},
journal = {Journal of Electronic Materials},
issn = {0361-5235},
number = 6,
volume = 41,
place = {United States},
year = {2012},
month = {1}
}

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