High Thermoelectric Performance SnTe with a Segregated and Percolated Structure

Area of Science:

• Materials Science
• Solid State Physics
• Nanotechnology

Background:

• Nanostructures are crucial for improving thermoelectric materials by enhancing power factors and reducing heat transfer.
• Tin telluride (SnTe) is a promising thermoelectric material, but its performance needs optimization.

Purpose of the Study:

• To develop a unique segregated and percolated (SP) microphase-separated structure to enhance the thermoelectric performance of SnTe.
• To investigate the effect of In/Mn codoping on the thermoelectric properties of the SP structure.

Main Methods:

• Fabrication of SP microphase-separated structures using SnTe and AgCuTe.
• Spark plasma sintering (SPS) process to induce solid-phase welding and form percolated layers.
• Cosubstitution of In and Mn into the SnTe lattice.

Main Results:

• The SP structure simultaneously scattered low-energy holes and phonons, leading to a high Seebeck coefficient (∼219.4 μV/K) and low lattice thermal conductivity (∼1.1 W m^-1 K^-1) at 800 K.
• In/Mn codoping further reduced lattice thermal conductivity to 0.47 W m^-1 K^-1.
• Achieved a peak figure of merit (ZT) of ∼1.45 at 800 K and an average ZT of ∼0.73 (400-800 K).

Conclusions:

• The SP structure effectively enhances thermoelectric performance in SnTe by optimizing electrical and thermal transport properties.
• The combination of SP structure and In/Mn codoping presents a viable strategy for developing high-performance thermoelectric materials.