Modulation of BiSb_2-Te₃ Alloy Application Temperature via Optimizing Material Composition

Area of Science:

• Materials Science
• Solid State Physics
• Thermoelectrics

Background:

• Bismuth telluride (Bi₂Te₃) alloys are key thermoelectric materials for refrigeration and power generation.
• Existing Bi₂Te₃ materials struggle to maintain optimal thermoelectric properties between 300-500 K.
• Tailoring alloy composition is crucial for expanding thermoelectric applications.

Purpose of the Study:

• To investigate the effect of bismuth (Bi) content on the thermoelectric properties of BiSb_2-Te₃ alloys.
• To identify the optimal Bi content for specific thermoelectric applications (refrigeration and power generation).
• To determine the best application temperature range for various Bi compositions.

Main Methods:

• Synthesis of a series of BiSb_2-Te₃ alloys with varying Bi content using a simple preparation method.
• Systematic investigation of thermoelectric properties, including carrier concentration and band gap modulation.
• Evaluation of the dimensionless figure of merit (ZT) across the 300-500 K temperature range.

Main Results:

• Bismuth content significantly influences carrier concentration and band gap in BiSb_2-Te₃ alloys.
• The alloy Bi_0.3Sb_1.7Te₃ (Bi content = 0.3) achieved a maximum ZT of 1.14 at 400 K.
• An average ZT of 1.06 was observed for Bi_0.3Sb_1.7Te₃ between 300-500 K, indicating suitability for both refrigeration and power generation.

Conclusions:

• BiSb_2-Te₃ alloys with Bi content < 0.3 are recommended for higher-temperature power generation.
• BiSb_2-Te₃ alloys with Bi content > 0.3 are suitable for lower-temperature refrigeration.
• This study provides guidance for optimizing Bi₂Te₃-based alloys for diverse thermoelectric applications.