Highly Integrated, Wearable Carbon-Nanotube-Yarn-Based Thermoelectric Generators Achieved by Selective Inkjet- Printed Chemical Doping

摘要

Flexible thermoelectrics that enable conformal contact with heat sourcesof arbitrary shape are indispensable for self-powered wearable electronics.Scalable integration of flexible thermoelectric (TE) materials into functionaldevices has improved over the past few years, however, the practical applicationsof flexible TE materials are still hindered by low performance. Herein,highly aligned carbon-nanotube yarns (CNTYs) are proposed, combined withselective doping via picoliter scale inkjet printing. Coagulation assisted byvan der Waals forces ensures a highly aligned structure of the CNTY, thusachieving the ultrahigh power factors of 4091 and 4739 μW m~（?1） K~（?2） for thep- and n-type, respectively. The proposed TE materials can be effortlessly upscaledinto highly integrated modules via inkjet printing. A highly integrated,flexible CNTY-based TE generator (TEG) with 600 PN pairs generates unparalleledmilliwatt-scale power at ΔT = 25 K, which is a few orders of magnitudehigher than those of previously reported flexible material-based TEGs. ThisTEG successfully powers a red light-emitting diode using body heat alone,requiring no external power sources. For the seamless operation of practicalapplications requiring high power, this work explores the key design parametersfor flexible TEGs with high performance and manufacturability andpresents new platforms for self-powered wearable electronics.