In:
Advanced Materials, Wiley, Vol. 30, No. 34 ( 2018-08)
Abstract:
Microstructure engineering is an effective strategy to reduce lattice thermal conductivity (κ l ) and enhance the thermoelectric figure of merit ( zT ). Through a new process based on melt‐centrifugation to squeeze out excess eutectic liquid, microstructure modulation is realized to manipulate the formation of dislocations and clean grain boundaries, resulting in a porous network with a platelet structure. In this way, phonon transport is strongly disrupted by a combination of porosity, pore surfaces/junctions, grain boundaries, and lattice dislocations. These collectively result in a ≈60% reduction of κ l compared to zone melted ingot, while the charge carriers remain relatively mobile across the liquid‐fused grains. This porous material displays a zT value of 1.2, which is higher than fully dense conventional zone melted ingots and hot pressed (Bi,Sb) 2 Te 3 alloys. A segmented leg of melt‐centrifuged Bi 0.5 Sb 1.5 Te 3 and Bi 0.3 Sb 1.7 Te 3 could produce a high device ZT exceeding 1.0 over the whole temperature range of 323–523 K and an efficiency up to 9%. The present work demonstrates a method for synthesizing high‐efficiency porous thermoelectric materials through an unconventional melt‐centrifugation technique.
Type of Medium:
Online Resource
ISSN:
0935-9648
,
1521-4095
DOI:
10.1002/adma.201802016
Language:
English
Publisher:
Wiley
Publication Date:
2018
detail.hit.zdb_id:
1474949-X
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