Triple Synergistic Modulation via Sn Doping in Tetrahedrites: Electronic Structure, DOS, and Scattering Engineering...

Area of Science:

• Materials Science
• Solid State Physics
• Thermoelectrics

Background:

• Thermoelectric materials are crucial for energy conversion, requiring high power factor and low thermal conductivity.
• Copper antimony sulfide (Cu₁₂Sb₄S₁₃) tetrahedrite shows promise but has limitations for further enhancement.
• Existing strategies include codoping and nanocomposites, but simpler methods are sought.

Purpose of the Study:

• To investigate tin (Sn) doping as a strategy to simultaneously improve electronic and thermal properties of Cu₁₂Sb₄S₁₃.
• To achieve enhanced thermoelectric performance without using nanocomposites.

Main Methods:

• Sn was doped at the antimony (Sb) site in the Cu₁₂Sb₄S₁₃ crystal structure.
• Measurements of electrical properties (power factor, hole concentration, density of states) and thermal conductivity were performed.
• The synergistic effects of Sn doping on electronic structure and phonon scattering were analyzed.

Main Results:

• Sn doping increased hole concentration and enhanced the density of states (DOS), significantly improving the power factor.
• Sn doping induced strong phonon scattering, reducing lattice thermal conductivity by approximately 69%.
• The optimized Cu₁₂Sb_3.96Sn_0.04S₁₃ sample achieved a figure of merit (ZT) of 1.26 at 750 K, a 126% increase.

Conclusions:

• Sn doping effectively and synergistically optimizes both electrical and thermal properties of Cu₁₂Sb₄S₁₃.
• This approach enhances thermoelectric performance through modulation of electronic structure, DOS, and phonon scattering.
• Sn doping presents a viable strategy for improving thermoelectric materials without complex fabrication methods like nanocomposites.