Improved Thermoelectric Performance of Tellurium by Alloying with a Small Concentration of Selenium to Decrease...

Area of Science:

• Materials Science
• Solid State Physics
• Thermoelectrics

Background:

• Phonon scattering via alloying is a key strategy for reducing lattice thermal conductivity.
• Alloying introduces mass differences and lattice strains, enhancing phonon scattering.
• Tellurium (Te) based materials are explored for their thermoelectric potential.

Purpose of the Study:

• To investigate the thermoelectric properties of tellurium (Te) between 323 and 623 K.
• To optimize Te's thermoelectric performance through selenium (Se) alloying and antimony (Sb) doping.

Main Methods:

• Alloying tellurium (Te) with varying concentrations of selenium (Se).
• Doping the Te-Se system with antimony (Sb) to increase carrier concentration.
• Characterization of thermoelectric properties, including lattice thermal conductivity and figure of merit (ZT).

Main Results:

• A minimum lattice thermal conductivity was achieved with approximately 10% Se alloying in Te.
• The figure of merit (ZT) increased by 60% due to reduced thermal conductivity and increased carrier concentration.
• An average ZT of ~0.8 was obtained for Te_0.88Se_0.10Sb_0.02, with an engineering ZT (ZT)_eng of ~0.5 and ~8% efficiency between 323-623 K.

Conclusions:

• Combining Se alloying and Sb doping effectively enhances the thermoelectric properties of Te.
• The optimized Te-Se-Sb system demonstrates significant potential for thermoelectric applications.
• The study highlights a successful strategy for improving thermoelectric materials through compositional engineering.