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Charge-Compensated Compound Defects in Ga-containing Thermoelectric Skutterudites

Qiu, Yuting and Xi, Lili and Shi, Xun and Qiu, Pengfei and Zhang, Wenqing and Chen, Lidong and Salvador, James R. and Cho, Jung Y. and Yang, Jihui and Chien, Yuan-chun and Chen, Sinn-Wen and Tang, Yinglu and Snyder, G. Jeffrey (2013) Charge-Compensated Compound Defects in Ga-containing Thermoelectric Skutterudites. Advanced Functional Materials, 23 (25). pp. 3194-3203. ISSN 1616-301X. http://resolver.caltech.edu/CaltechAUTHORS:20130828-102406743

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Abstract

Heavy doping changes an intrinsic semiconductor into a metallic conductor by the introduction of impurity states. However, Ga impurities in thermoelectric skutterudite CoSb_3 with lattice voids provides an example to the contrary. Because of dual-site occupancy of the single Ga impurity charge-compensated compound defects are formed. By combining first-principle calculations and experiments, we show that Ga atoms occupy both the void and Sb sites in CoSb_3 and couple with each other. The donated electrons from the void-filling Ga (GaVF) saturate the dangling bonds from the Sb-substitutional Ga (Ga_(Sb)). The stabilization of Ga impurity as a compound defect extends the region of skutterudite phase stability toward Ga_(0.15)Co_4Sb_(11.95) whereas the solid–solution region in other directions of the ternary phase diagram is much smaller. A proposed ternary phase diagram for Ga-Co-Sb is given. This compensated defect complex leads to a nearly intrinsic semiconductor with heavy Ga doping in CoSb_3 and a much reduced lattice thermal conductivity (κ_L) which can also be attributed to the effective scattering of both the low- and high-frequency lattice phonons by the dual-site occupant Ga impurities. Such a system maintains a low carrier concentration and therefore high thermopower, and the thermoelectric figure of merit quickly increases to 0.7 at a Ga doping content as low as 0.1 per Co_4Sb_(12) and low carrier concentrations on the order of 10^(19) cm^(−3).


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1002/adfm.201202571 DOIArticle
http://onlinelibrary.wiley.com/doi/10.1002/adfm.201202571/abstractPublisherArticle
ORCID:
AuthorORCID
Snyder, G. Jeffrey0000-0003-1414-8682
Additional Information:© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim. Received: September 7, 2012; Revised: December 10, 2012; Published online: February 6, 2013. This work was supported by the National Basic Research Program of China (973-program) under Project No. 2013CB632501, the National Natural Science Foundation of China (NSFC) under the Nos. 11234012, 51222209, 51121064, and 50825205, the Shanghai Science and Technology Commission (Pujiang Program, 11PJ1410200). J.Y. thanks the NSFC (51028201) and NSFC-CAS/SAFEA International Partnership Program for Creative Research Teams, and International S&T Cooperation Program of China (2011DFB60150). J.R.S. and J.Y.C. acknowledge the support by GM and by the DOE under corporate agreement DE-FC26- 04NT42278. X.S., J.Y., J.R.S., and J.Y.C. thank J. F. Herbst and M. W. Verbrugge for their continued support and encouragement. G.J.S. and S.W.C. thank the joint Caltech-Taiwan NSC program under the No. 101-3113-P-008-001.
Group:Resnick Sustainability Institute
Funders:
Funding AgencyGrant Number
National Basic Research Program of China 973 Program2013CB632501
National Natural Science Foundation of China (NSFC)11234012
National Natural Science Foundation of China (NSFC)51222209
National Natural Science Foundation of China (NSFC)51121064
National Natural Science Foundation of China (NSFC)50825205
Shanghai Science and Technology Commission Pujiang Program11PJ1410200
National Natural Science Foundation of China (NSFC)51028201
NSFC-CAS/SAFEA International Partnership Program for Creative Research TeamsUNSPECIFIED
International S&T Cooperation Program of China2011DFB60150
GMUNSPECIFIED
Department of Energy (DOE)DE-FC26-04NT42278
Caltech-Taiwan NSC Program101-3113-P-008-001
Subject Keywords:thermoelectrics; semiconductors; doping; electrical and thermal transports
Record Number:CaltechAUTHORS:20130828-102406743
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20130828-102406743
Official Citation:Qiu, Y., Xi, L., Shi, X., Qiu, P., Zhang, W., Chen, L., Salvador, J. R., Cho, J. Y., Yang, J., Chien, Y.-c., Chen, S.-w., Tang, Y. and Snyder, G. J. (2013), Charge-Compensated Compound Defects in Ga-containing Thermoelectric Skutterudites. Adv. Funct. Mater., 23: 3194–3203. doi: 10.1002/adfm.201202571
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:40971
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:30 Aug 2013 17:57
Last Modified:02 Mar 2017 20:25

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