Direct Ink Writing of Three-Dimensional Thermoelectric Materials and Devices

Abstract

Heat is omnipresent in natural and artificial environments, more than 60% of which is dissipated. Thermoelectric (TE) power generation can provide a unique solution to convert this dissipated, wasted heat into useful energy, that is, electricity. Generally, TE conversion efficiency depends on the material properties and design of the module structure. The geometrical design of thermoelectric legs in modules is important to ensure high power generation but cannot be easily achieved by traditional fabrication processes. At this moment, three-dimensional (3D) printing technology can maximize the flexibility in the design and fabrication of TE modules into more efficient structures. Furthermore, the printing process can significantly reduce the processing cost for the fabrication of TE modules owing to lower energy input and a simplified assembly process. Herein, I present the development of the 3D direct ink writing process applied to a range of different TE materials of Bi2Te3, BiSbTe, PbTe, and Cu2Se-based inorganic alloys. Surface states of TE particles were precisely optimized with the controllable charge states in the presence of anionic inorganic binders, achieving the suitable viscoelasticity of the TE inks to the direct ink writing. The geometrically designed 3D-written TE materials were assembled into power generating systems, in which high efficiencies of energy conversion were achieved by the optimization of heat transfer.