Rapid fabrication and thermoelectric performance of SnTe via non-equilibrium laser 3D printing

Thermoelectric technologies based on Seebeck and Peltier effects, as energy techniques able to directly convert heat into electricity and vice versa, hold promise for addressing the global energy and environmental problems. The development of efficient and low-cost thermoelectric modules is the key to their large-scale commercial applications. In this paper, using a non-equilibrium laser 3D printing technique, we focus an attention on the fabrication of mid-temperature p-type SnTe thermoelectric materials. The influence of laser power, scanning speed and layer thickness on the macro-defects, chemical and phase composition, microstructure and thermoelectric performance was systematically investigated. First and foremost, the processing parameter window for printing a high-quality layer is determined. This is followed by the finite element method used to simulate and verify the influence of the laser-induced molten pool temperature distribution on the final composition and microstructure. Finally, the high-performance SnTe layer with 10 mm × 10 mm in area is produced within seconds with room temperature Seebeck coefficient close to that of SnTe manufactured by the traditional methods. Consequently, this work lays a solid foundation for the future fabrication of thermoelectric modules using laser non-equilibrium printing techniques.