Highly Textured N-Type SnSe Polycrystals with Enhanced Thermoelectric Performance

Area of Science:

• Materials Science
• Solid State Physics
• Energy Conversion

Background:

• Thermoelectric materials convert heat to electricity via the Seebeck effect, crucial for refrigeration and waste heat recovery.
• Tin selenide (SnSe) shows promise, especially n-type SnSe, due to its unique 3D charge and 2D phonon transport properties enhancing thermoelectric performance.

Purpose of the Study:

• Investigate the thermoelectric transport properties of n-type polycrystalline SnSe.
• Focus on out-of-plane transport by creating a specific textural microstructure.
• Achieve anisotropic transport properties similar to crystalline SnSe.

Main Methods:

• Fabrication of textured n-type polycrystalline SnSe using mechanical alloying and repeated spark plasma sintering (SPS).
• Characterization of thermoelectric transport properties, including thermal conductivity and electrical power factor.
• Analysis of the influence of textural microstructure on transport anisotropy.

Main Results:

• Achieved a low thermal conductivity of 0.36 W m^-1 K^-1 perpendicular to the texture direction at 783 K.
• Observed nearly isotropic electrical transport properties with a high power factor reaching 681.3 μW m^-1 K^-2 at 783 K.
• Reached a maximum thermoelectric figure of merit (ZT) of 1.5 at 783 K due to combined isotropic power factor and anisotropic thermal conductivity.

Conclusions:

• The study demonstrates outstanding electrical and thermal transport behaviors in n-type polycrystalline SnSe with controlled texture.
• Optimizing texture in n-type polycrystalline SnSe offers a pathway to higher thermoelectric performance.
• The findings highlight the potential of textured n-type SnSe for efficient thermoelectric energy conversion.