In situ characterisation of nanostructured multiphase thermoelectric materials at elevated temperatures
S Aminorroaya Yamini1, D R G Mitchell1, M Avdeev2
1Australian Institute for Innovative Materials (AIIM), Innovation Campus, University of Wollongong, Squire Way, North Wollongong, NSW 2500, Australia. Sima@uow.edu.au.
Physical Chemistry Chemical Physics : PCCP
|November 24, 2016
Summary
This study investigates multiphase thermoelectric materials, revealing how sodium doping influences their structural evolution and precipitate behavior at high temperatures. Understanding these changes is key to designing more efficient thermoelectric devices.
Area of Science:
- Materials Science
- Solid State Physics
- Chemistry
Background:
- Multiphase thermoelectric materials offer higher efficiencies than single-phase counterparts.
- Limited understanding exists regarding the temperature-dependent structural evolution of these multiphase systems.
Purpose of the Study:
- To investigate the in situ structural evolution of multiphase (PbTe)0.65(PbS)0.25(PbSe)0.1 thermoelectric compounds at high temperatures.
- To determine the effect of sodium doping on the microstructural evolution and phase behavior.
Main Methods:
- In situ high-temperature characterization using hot stage transmission electron microscopy (TEM).
- High-resolution neutron powder diffraction (NPD) for precise structural analysis.
- Analysis of materials with varying sodium doping concentrations (heavy and light).
Main Results:
- Observed microstructural evolution of precipitates and determined phase lattice parameters as a function of temperature.
- Sodium doping was found to distribute heterogeneously, optimizing charge carrier concentration.
- Secondary phase dissolution occurred at elevated temperatures, with kinetics influenced by sodium doping levels.
Conclusions:
- Sodium doping significantly affects the kinetics of precipitation, enabling heavily doped samples to reach equilibrium faster.
- The findings provide crucial insights for the rational design of high-performance multiphase thermoelectric materials.
- Understanding structural evolution under thermal stress is vital for optimizing thermoelectric device performance.
