Experimental_ΤΕG-electronic board charging@ΔΤ 25K_Characterisation_WP6_PDOT

Three-dimensional (3D) printed thermoplastic polyurethane (TPU) gyroid micro-porous structures are fabricated and utilized for the infiltration of p- and n-type single wall carbon nanotubes (SWCNT) as p- and n-type thermoelements of a high-performance thermoelectric generator (TEG) device. Aqueous based thermoelectric inks are initially prepared using an appropriate amount of SWCNTs and additives allowing a p- or n-type semi-conducting character based on non-covalent molecular interactions. The tailored inks are subsequently deposited in 3D printed (3DP) gyroid structures through a scalable dip-coating process, resulting in p- and n-type “segregated” SWCNT continuous nanolayers within the TPU pores. The attained TPU/SWCNT cylindrically shaped thermoelements exhibited Seebeck coefficient values of +32.16 ± 1.11 μV⋅K-1 (TPU/p-SWCNT) and -38.42 ± 2.49 μV⋅K-1 (TPU/n-SWCNT), respectively. A TEG device is finally assembled through the serial interconnection of 120 p-n junctions on a TPU matrix, capable of generating a power output (Pout) of 203.08 μW at an applied through-thickness temperature gradient (ΔT) of 80Κ. The TEG performance was validated by finite element (FE) analysis. The TEG device exhibits the potential to efficiently charge a commercial DC-DC step-up converter within an elapsed time of 408 s at a ΔT = 25Κ, generating sufficient power for the illumination of a green LED. This work introduces, for the first time, a thermoelectric generator (TEG) device that integrates p-and n-type single-walled carbon nanotubes (SWCNTs) within topologically optimized 3D printed TPU gyroid scaffolds, creating segregated conductive structures. Unlike prior studies that focus on dense or inorganic thermoelements, this approach enables scalable, environmentally benign fabrication of high-performance organic TEG devices. It can be envisaged that the proposed device fabrication process exhibits high scalability potential, while the final high-performance and lightweight TEG could serve numerous applications, i.e. harvesting wasted heat towards self-powered electronics, IoT sensors, etc.