Realizing High Thermoelectric Performance in ZnCl₂-Doped N-Type Polycrystalline SnSe Through Band Engineering and...

Area of Science:

• Materials Science
• Solid State Physics
• Nanotechnology

Background:

• Tin selenide (SnSe)-based compounds are promising thermoelectric materials due to low thermal conductivity.
• Improving the electrical transport capacity of n-type polycrystalline SnSe is crucial for enhanced thermoelectric performance.

Purpose of the Study:

• To investigate the effect of zinc chloride (ZnCl2) doping on the thermoelectric properties of n-type SnSe.
• To enhance the electrical transport and reduce thermal conductivity of n-type SnSe.

Main Methods:

• ZnCl2 doping was employed to modify the electronic structure and introduce defects in n-type SnSe.
• Thermoelectric properties, including electrical transport coefficient and thermal conductivity, were analyzed.
• The figure of merit (zT) was evaluated at elevated temperatures.

Main Results:

• ZnCl2 doping enhanced the density of state effective mass and facilitated multivalley degeneracy, improving electrical transport.
• Multiple defects, including precipitates and twin boundaries, effectively reduced lattice thermal conductivity.
• A maximum zT of approximately 1.3 was achieved for SnSe0.95-2%ZnCl2 at 873 K, a four-fold increase over pristine SnSe.

Conclusions:

• ZnCl2 doping is an effective strategy for enhancing the thermoelectric performance of n-type polycrystalline SnSe.
• The study demonstrates a cost-effective and environmentally friendly approach for thermoelectric material optimization.
• The enhanced zT suggests potential for SnSe-based materials in waste heat recovery applications.