Screen-Printable p- and n‑Type Functionalized Graphene Inks for Flexible Textile Thermoelectric Generators

Wearable thermoelectric (TE) generators offer a sustainable solution for powering low-energy electronics by harvesting body heat. In this study, we report the development of fully screen-printable, solution-processed graphene inks exhibiting p- and n-type thermoelectric behavior for flexible textile applications. The inks were printed onto woven cotton substrates by using scalable screen-printing methods, forming all-graphene thermoelectric modules that retain textile flexibility and breathability. Electrical characterization demonstrated Seebeck coefficients of +34 μV/K. Under a modest temperature gradient of 40 °C, the TE textile device generated open-circuit voltages up to 5.24 mV with stable operation. The materials and device exhibited good adhesion, flexibility, and thermal response without requiring postprocessing or high-temperature annealing. This work presents a cost-effective, scalable, and environmentally benign approach to fabricating wearable thermoelectric systems, offering strong potential for powering flexible electronics, health monitoring sensors, and future energy-autonomous garments.