Highly Deformable Van der Waals Chalcogenides with Superior Thermoelectric Performance from Interpretable Machine...

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Flexible thermoelectric devices are crucial for wearable electronics.
• Finding materials with both high flexibility and thermoelectric efficiency (ZT) is challenging.
• A high-throughput screening method is needed to identify suitable van der Waals (vdW) chalcogenides.

Purpose of the Study:

• To develop and apply a high-throughput screening method for vdW chalcogenides.
• To identify flexible vdW chalcogenides with superior thermoelectric properties.
• To discover novel materials for advanced flexible thermoelectric devices.

Main Methods:

• Screened over 1000 vdW chalcogenides using a high-throughput computational approach.
• Evaluated material flexibility using a previously established deformability factor.
• Predicted thermoelectric figure of merit (ZT) values using a machine learning model.
• Conducted first-principles calculations for promising candidate materials.

Main Results:

• Identified several vdW chalcogenide candidates exhibiting both high deformability and favorable ZT values.
• NbSe2Br2 was identified as a top-performing material, achieving a maximum ZT of 1.35 at 1000 K.
• NbSe2Br2 demonstrated a power factor of 8.1 µW cm⁻¹K⁻² at 300 K, outperforming many existing flexible thermoelectric materials.
• Attributed high ZTmax to low thermal conductivity and high Seebeck coefficient in the out-of-plane direction.

Conclusions:

• The study successfully identified promising vdW chalcogenides for flexible thermoelectric applications.
• NbSe2Br2 represents a significant advancement in flexible inorganic thermoelectric materials.
• The findings provide new material options for developing next-generation wearable electronic devices.