Additive Manufacturing of Thermoelectrics: Emerging Trends and Outlook

Additive manufacturing (AM) has progressed rapidly in recent years, thanks to its versatility in printing complex and intricate shapes. Very recently, it has also been making inroads into functional and energy materials. On the other hand, thermoelectrics is a relatively mature field, with well-established understanding and design, especially on the materials level. However, complexities in device fabrication and scalability issues have greatly hindered thermoelectric (TE) applications. In this Focus Review, we discuss the advent of AM as a timely and important tool not only to overcome the scalability issues but also to achieve shape intricacies and conformability for flexible and wearable applications. In particular, direct ink writing (DIW), a subset under materials extrusion methods, holds great promise as a versatile fabrication technique for integrated TE devices. More importantly, we discuss the great promise of "engineered nanostructuring" using DIW as a new paradigm to improve TE performance beyond intrinsic properties.