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Enhanced Thermoelectric Properties in Bulk Nanowire Heterostructure-Based Nanocomposites through Minority Carrier Blocking

Yang, Haoran and Bahk, Je-Hyeong and Day, Tristan and Mohammed, Amr M. S. and Snyder, G. Jeffrey and Shakouri, Ali and Wu, Yue (2015) Enhanced Thermoelectric Properties in Bulk Nanowire Heterostructure-Based Nanocomposites through Minority Carrier Blocking. Nano Letters, 15 (2). pp. 1349-1355. ISSN 1530-6984.

[img] PDF (Detailed experimental processes, theoretical modeling procedures, schematic presentation of the lattice mismatch between Te(001) planes and PbTe(111) planes, and HRTEM images showing the junctions of several PbTe−Ag_2Te heterostructures) - Supplemental Material
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To design superior thermoelectric materials the minority carrier blocking effect in which the unwanted bipolar transport is prevented by the interfacial energy barriers in the heterogeneous nanostructures has been theoretically proposed recently. The theory predicts an enhanced power factor and a reduced bipolar thermal conductivity for materials with a relatively low doping level, which could lead to an improvement in the thermoelectric figure of merit (ZT). Here we show the first experimental demonstration of the minority carrier blocking in lead telluride–silver telluride (PbTe–Ag_2Te) nanowire heterostructure-based nanocomposites. The nanocomposites are made by sintering PbTe–Ag_2Te nanowire heterostructures produced in a highly scalable solution-phase synthesis. Compared with Ag_2Te nanowire-based nanocomposite produced in similar method, the PbTe–Ag_2Te nanocomposite containing ∼5 atomic % PbTe exhibits enhanced Seebeck coefficient, reduced thermal conductivity, and ∼40% improved ZT, which can be well explained by the theoretical modeling based on the Boltzmann transport equations when energy barriers for both electrons and holes at the heterostructure interfaces are considered in the calculations. For this p-type PbTe–Ag_2Te nanocomposite, the barriers for electrons, that is, minority carriers, are primarily responsible for the ZT enhancement. By extending this approach to other nanostructured systems, it represents a key step toward low-cost solution-processable nanomaterials without heavy doping level for high-performance thermoelectric energy harvesting.

Item Type:Article
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URLURL TypeDescription Information
Snyder, G. Jeffrey0000-0003-1414-8682
Additional Information:© 2015 American Chemical Society. Received: December 2, 2014; Revised: December 23, 2014; Published: January 9, 2015. Y.W. led the project. H.Y. was the main contributor for the PbTe−Ag_2Te heterostructure synthesis, nanocomposite fabrications, and structural characterizations. J.-H.B. and A.S. performed the theoretical modeling. T.D. and G.J.S. performed the electrical conductivity measurements. H.Y. and A.M.S.M. performed Seebeck coefficient measurements. Funding: This work is supported by US Air Force Office of Scientific Research (Award Number FA9550-12-1-0061).
Funding AgencyGrant Number
Air Force Office of Scientific Research (AFOSR)FA9550-12-1-0061
Subject Keywords:Thermoelectric; heterostructures; PbTe; Ag2Te; nanocomposites; minority carrier blocking
Issue or Number:2
Record Number:CaltechAUTHORS:20150324-102155798
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Official Citation:Enhanced Thermoelectric Properties in Bulk Nanowire Heterostructure-Based Nanocomposites through Minority Carrier Blocking Haoran Yang, Je-Hyeong Bahk, Tristan Day, Amr M. S. Mohammed, G. Jeffrey Snyder, Ali Shakouri, and Yue Wu Nano Letters 2015 15 (2), 1349-1355 DOI: 10.1021/nl504624r
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:56014
Deposited By: Tony Diaz
Deposited On:24 Mar 2015 17:35
Last Modified:03 Oct 2019 08:10

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