Spinodal decomposition and nucleation and growth as a means to bulk nanostructured thermoelectrics: Enhanced performance in Pb1-xSn xTe-PbS

John Androulakis, Chia Her Lin, Hun Jin Kong, Ctirad Uher, Chun I. Wu, Timothy Hogan, Bruce A. Cook, Thierry Caillat, Konstantinos M. Paraskevopoulos, Mercouri G. Kanatzidis*

*此作品的通信作者

研究成果: 雜誌貢獻期刊論文同行評審

419 引文 斯高帕斯(Scopus)

摘要

The solid-state transformation phenomena of spinodal decomposition and nucleation and growth are presented as tools to create nanostructured thermoelectric materials with very low thermal conductivity and greatly enhanced figure of merit. The systems (PbTe)1-x(PbS)x and (Pb 0.95Sn0.05Te)1-x(PbS)x are not solid solutions but phase separate into PbTe-rich and PbS-rich regions to produce coherent nanoscale heterogeneities that severely depress the lattice thermal conductivity. For x gt; ∼0.03 the materials are ordered on three submicrometer length scales. Transmission electron microscopy reveals both spinodal decomposition and nucleation and growth phenomena the relative magnitude of which varies with x. We show that the (Pb0.95Sn 0.05Te)1-x(PbS)x system, despite its nanostructured nature, maintains a high electron mobility (> 100 cm 2/V·s at 700 K). At x ∼ 0.08 the material achieves a very low room-temperature lattice thermal conductivity of ∼0.4 W/m·K. This value is only 28% of the PbTe lattice thermal conductivity at room temperature. The inhibition of heat flow in this system is caused by nanostructure-induced acoustic impedance mismatch between the PbTe-rich and PbS-rich regions. As a result the thermoelectric properties of (Pb0.95Sn0.05Te) 1-x(PbS)x at x = 0.04, 0.08, and 0.16 were found to be superior to those of PbTe by almost a factor of 2. The relative importance of the two observed modes of nanostructuring, spinodal decomposition and nucleation and growth, in suppressing the thermal conductivity was assessed in this work, and we can conclude that the latter mode seems more effective in doing so. The promise of such a system for high efficiency is highlighted by a ZT ∼ 1.50 at 642 K for x ∼ 0.08.

原文英語
頁(從 - 到)9780-9788
頁數9
期刊Journal of the American Chemical Society
129
發行號31
DOIs
出版狀態已發佈 - 2007 8月 8
對外發佈

ASJC Scopus subject areas

  • 催化
  • 一般化學
  • 生物化學
  • 膠體和表面化學

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