Large-scale SHS based 3D printing of high-performance n-type BiTeSe: Comprehensive development from materials to modules

Abstract

Micro thermoelectric devices have a broad application prospect in confined space refrigeration and power generation of small nodes in the Internet of things. The leg performance, manufacturing efficiency and yield are very important for the industrial production of thermoelectric devices. Here, self-propagating high-temperature synthesis (SHS) and selective laser melting (SLM) technique are combined to directly form a dense and highly growth-oriented n-type BiTeSe material in large scale from raw materials of Bi, Te and Se powders. Ignoring the solid solution of a small amount of Se, the composition and structure analysis of the micro-region via transmission electron microscopy shows that Bi first reacts with Te to form BiTe compound in the molten pool of laser, and then Te reacts with the intermediate BiTe to form Bi2Te3 phase. In the next manufacturing process, a thin bulk material with a size of 60 × 30 × 0.5 mm3 can be printed out within 1 h. Because of the excellent mechanical properties, 4000 valid legs with a size of 0.4 mm × 0.4 mm in plane can be obtained successfully. Finally, a micro thermoelectric device is fabricated via using 3D-printed n-type BiTeSe and commercially hot extrusion p-type BiSbTe legs (28 pairs). For solid refrigeration, the maximum cooling temperature difference is about 44 °C and the maximum cooling power Qmax of the device is about 2.1 W when the input current Imax is about 1.1 A. For power generation, the open-circuit voltage Uoc is 324 mV and the maximum output power Pmax is 4.97 mW when ΔT is 40 K.