Roll-to-roll printing of spatial wearable thermoelectrics

With the increasing demand for self-powered wearable electronics, wearable thermoelectric devices provide a unique mode for energy conversion from body waste heat into electricity; however, most of current efforts are made to mass-produce in-plane thin film TEG, where heat transports in-plane, making it difficult in integration into the practical energy systems. The lack of effective approach for scalable manufacturing of spatial thermoelectrics significantly restricts their application for wearable electronics. In this paper, we develop a novel roll-to-roll system incorporated with the spatial extrusion printing technique for manufacturing large-scale flexible thermoelectric devices using single-walled carbon nanotubes (SWCNT) based all-organic p- and n-type thermoelectrics. SWCNT composites were scalable assembled for spatial thermoelectric architecture and demonstrated a maximum power density of ∼1.49 mW/m² and a maximum voltage of ∼20 mV at a temperature gradient of 25 K. As-printed SWCNT composites architecture were also used as a power supply for LED diode, demonstrating the possibility of harvesting body heat to power the wearable electronics.