Post-Electric Current Treatment Approaching High-Performance Flexible n-Type Bi₂Te₃ Thin Films

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Flexible thermoelectric materials are crucial for wearable electronics and energy harvesting.
• Bismuth telluride (Bi2Te3) is a leading near-room temperature thermoelectric material, but its performance in flexible formats requires optimization.

Purpose of the Study:

• To improve the thermoelectric performance of inorganic n-type Bi2Te3 flexible thin films.
• To investigate the effect of post-electric current treatment on the electrical properties and mechanical stability of Bi2Te3 films.

Main Methods:

• Fabrication of n-type Bi2Te3 flexible thin films.
• Application of post-electric current treatment with varying current densities.
• Characterization of electrical conductivity, carrier concentration, power factor, and bending resistance.
• Fabrication and testing of a flexible thermoelectric device.

Main Results:

• Post-electric current treatment increased carrier concentration and electrical conductivity (1874 to 2240 S cm−1).
• A high power factor of ~10.70 μW cm−1 K−2 was achieved at room temperature with 0.5 A treatment.
• The treated films exhibited excellent bending resistance with <10% change in relative resistance after bending.
• A flexible device demonstrated an open circuit voltage of ~7.96 mV and output power of 24.78 nW at a 35 K temperature difference.

Conclusions:

• Post-electric current treatment is an effective strategy to enhance the electrical performance of flexible Bi2Te3 thin films.
• The optimized films show promise for practical flexible thermoelectric applications.
• The study highlights the potential of Bi2Te3 for wearable thermoelectric generators.