Next Article in Journal
Size and Shape Controlled Crystallization of Hemoglobin for Advanced Crystallography
Next Article in Special Issue
Solvent-Dependent Thermoelectric Properties of PTB7 and Effect of 1,8-Diiodooctane Additive
Previous Article in Journal
Light-Induced Current Oscillations in the Charge-Ordered State of (TMTTF)2SbF6
Previous Article in Special Issue
Spark Plasma Sintering of Tungsten Oxides WOx (2.50 ≤ x ≤ 3): Phase Analysis and Thermoelectric Properties
Article Menu
Issue 9 (September) cover image

Export Article

Open AccessArticle
Crystals 2017, 7(9), 281; doi:10.3390/cryst7090281

Microstructure Evolution of Ag-Alloyed PbTe-Based Compounds and Implications for Thermoelectric Performance

1
The Nancy and Stephen Grand Technion Energy Program (GTEP), Technion-Israel Institute of Technology, Haifa 32000, Israel
2
Department of Materials Science and Engineering, Technion-Israel Institute of Technology, Haifa 32000, Israel
3
Department of Materials Engineering, Faculty of Engineering Sciences, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel
*
Author to whom correspondence should be addressed.
Academic Editor: Shujun Zhang
Received: 17 August 2017 / Revised: 8 September 2017 / Accepted: 12 September 2017 / Published: 18 September 2017
(This article belongs to the Special Issue Materials Processing and Crystal Growth for Thermoelectrics)
View Full-Text   |   Download PDF [2920 KB, uploaded 18 September 2017]   |  

Abstract

We investigate the microstructure evolution of Ag-alloyed PbTe compounds for thermoelectric (TE) applications with or without additions of 0.04 at. % Bi. We control the nucleation and temporal evolution of Ag2Te-precipitates in the PbTe-matrix applying designated aging heat treatments, aiming to achieve homogeneous dispersion of precipitates with high number density values, hypothesizing that they act as phonon scattering centers, thereby reducing lattice thermal conductivity. We measure the temperature dependence of the Seebeck coefficient and electrical and thermal conductivities, and correlate them with the microstructure. It is found that lattice thermal conductivity of PbTe-based compounds is reduced by controlled nucleation of Ag2Te-precipitates, exhibiting a number density value as high as 2.7 × 1020 m−3 upon 6 h aging at 380 °C. This yields a TE figure of merit value of ca. 1.4 at 450 °C, which is one on the largest values reported for n-type PbTe compounds. Subsequent aging leads to precipitate coarsening and deterioration of TE performance. Interestingly, we find that Bi-alloying improves the alloys’ thermal stability by suppressing microstructure evolution, besides the role of Bi-atoms as electron donors, thereby maintaining high TE performance that is stable at elevated service temperatures. The latter has prime technological significance for TE energy conversion. View Full-Text
Keywords: thermoelectric materials; PbTe; thermal conductivity; phonon scattering; phase transformations; microstructure evolution thermoelectric materials; PbTe; thermal conductivity; phonon scattering; phase transformations; microstructure evolution
Figures

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (CC BY 4.0).

Scifeed alert for new publications

Never miss any articles matching your research from any publisher
  • Get alerts for new papers matching your research
  • Find out the new papers from selected authors
  • Updated daily for 49'000+ journals and 6000+ publishers
  • Define your Scifeed now

SciFeed Share & Cite This Article

MDPI and ACS Style

Grossfeld, T.; Sheskin, A.; Gelbstein, Y.; Amouyal, Y. Microstructure Evolution of Ag-Alloyed PbTe-Based Compounds and Implications for Thermoelectric Performance. Crystals 2017, 7, 281.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics

1

Comments

[Return to top]
Crystals EISSN 2073-4352 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top