Coupled Vacancy and Phonon-Scattering Engineering Drive Defect Evolution Toward Multifunctional High-Performance...

Area of Science:

• Materials Science
• Solid-State Physics
• Sustainable Energy

Background:

• Bismuth telluride (Bi2Te3)-based compounds are key for near-room-temperature thermoelectric applications.
• Current limitations include moderate efficiency, poor mechanical robustness, and limited multifunctionality.

Purpose of the Study:

• To develop a dual-regulation strategy using ZnSb and Se dopants to improve carrier and phonon transport in Bi2Te3-based materials.
• To enhance thermoelectric performance, mechanical properties, and device functionality.

Main Methods:

• Integration of intermetallic ZnSb and Se dopants into Bi0.4Sb1.6Te3.01.
• Synergistic modulation of carrier concentration and phonon scattering.
• Characterization of thermoelectric properties (Seebeck coefficient, power factor, zT), mechanical strength (Vickers hardness, compressive strength), and device performance (cooling temperature difference, power generation efficiency).

Main Results:

• Optimized composition (Bi0.4Sb1.6Te2.97Se0.04 + 0.15% ZnSb) achieved a peak thermoelectric figure of merit (zT) of ~1.51 at 353 K.
• Demonstrated enhanced mechanical properties with Vickers hardness of ~97 Hv and compressive strength of ~188 MPa.
• A multifunctional device achieved a ~70 K cooling temperature difference and ~7.1% power generation efficiency.

Conclusions:

• The dual-regulation strategy effectively enhances thermoelectric performance and mechanical integrity.
• The developed materials and design framework enable practical, multifunctional Bi2Te3-based thermoelectric devices for cooling and energy harvesting.
• Achieved exceptional stability for room-temperature wearable applications.