All-SnTe-Based Thermoelectric Power Generation Enabled by Stepwise Optimization of n-Type SnTe

Area of Science:

• Materials Science
• Solid State Physics
• Energy Conversion

Background:

• High-performance n-type and p-type thermoelectric materials are crucial for practical device applications.
• Environmentally friendly tin telluride (SnTe) shows promise, but developing high-performance n-type SnTe is essential.
• Existing p-type SnTe research necessitates comparable n-type counterparts for device reliability.

Purpose of the Study:

• To optimize the thermoelectric transport properties of n-type SnTe.
• To develop a high-performance n-type SnTe material for mid-temperature power generation.
• To fabricate and evaluate an all-SnTe-based thermoelectric device.

Main Methods:

• Stepwise optimization strategy involving PbSe alloying to narrow the band gap and enhance n-type dopability.
• Introduction of additional Pb atoms to compensate for cationic vacancies and increase electron carrier concentration.
• Fabrication of an all-SnTe-based seven-pair thermoelectric device using the optimized n-type SnTe.

Main Results:

• Achieved a peak thermoelectric figure of merit (ZT) of ~0.75 at 573 K for n-type SnTe.
• Obtained a high average ZT (ZTave) exceeding 0.5 across a wide temperature range (300–823 K).
• Demonstrated a maximum output power of ~0.2 W and 2.7% conversion efficiency in the all-SnTe device under a 350 K temperature difference.

Conclusions:

• The stepwise optimization strategy significantly enhances the thermoelectric performance of n-type SnTe.
• The developed n-type SnTe shows excellent potential for mid-temperature power generation applications.
• The successful fabrication of the all-SnTe device marks a breakthrough, highlighting the viability of SnTe-based thermoelectrics.