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Thermoelectric properties of Bi2Te3-PbTe pseudo binary near the eutectic composition
Kyooho Jung1, Ho Won Jang, Chong-Yun Kang
1Electronic Materials Center Korea Institute of Science and Technology, Seoul 136-791, Korea.
Journal of Nanoscience and Nanotechnology
|August 2, 2012
Summary
Phase separation in bismuth telluride-lead telluride alloys enhances thermoelectric performance by reducing thermal conductivity. This study investigates these (Bi2Te3)(1-x)(PbTe)(x) systems, revealing p-type to n-type conversion and improved properties.
Area of Science:
- Materials Science
- Solid State Physics
- Thermoelectrics
Background:
- Bismuth telluride (Bi2Te3) and lead telluride (PbTe) are key thermoelectric materials.
- Controlling microstructure is crucial for optimizing thermoelectric properties.
- Phase separation can significantly alter material characteristics.
Purpose of the Study:
- To investigate the microstructure and thermoelectric properties of (Bi2Te3)(1-x)(PbTe)(x) binary systems.
- To understand the effects of phase separation near the eutectic composition.
- To explore the relationship between microstructure and thermoelectric performance.
Main Methods:
- Preparation of (Bi2Te3)(1-x)(PbTe)(x) alloys via melting of elemental metals.
- Sequential water quenching process to control solidification.
- Microstructural analysis and measurement of thermoelectric properties.
Main Results:
- Phase separation into Bi2Te3, BiPbTe, and PbTe phases observed for compositions above the eutectic point.
- Electrical conduction type conversion from p-type to n-type in phase-separated alloys.
- Reduced lattice thermal conductivity in phase-separated alloys due to increased boundary scattering.
Conclusions:
- Phase separation in (Bi2Te3)(1-x)(PbTe)(x) alloys is controllable by composition.
- Phase separation leads to significant changes in electrical and thermal transport properties.
- The observed reduction in thermal conductivity suggests potential for enhanced thermoelectric figure of merit.
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