Abstract: Due to its ability to convert body heat into electricity, organic thermoelectric material is considered a promising and smart maintenance-free power source to charge wearable electronics. However, developing flexible n-type organic thermoelectric materials and wearable p/n junction thermoelectric devices remains challenging. In this work, two insulated polyamides (PA6 and PA66) that have been widely used as fiber materials are employed as novel dopants for converting p-type single-walled carbon nanotubes (SWCNTs) to n-type thermoelectric materials. Because of the electron transferability of the amide group, polyamide-doped SWCNTs exhibit excellent thermopower values as large as -56.0 µV K^-1 for PA66, and -54.5 µV K^-1 for PA6. Thermoelectric devices with five p/n junctions connected in series are fabricated. The testing device produces a thermoelectric voltage of 43.1 mV and generates 1.85 µW thermoelectric power under temperature gradients of approximately 80 K. Furthermore, they display charming capability for temperature recognition and monitoring human activities as sensors. These promising results suggest that the flexible polyamide-doped SWCNT composites herein have high application potential as wearable thermoelectric electronics.

Key words: N-type thermoelectric material, Self-powered sensors, Composites, Single-walled carbon nanotubes, Wearable electronics