Flexible Films of Poly(3,4-Ethylenedioxythiophene):Poly(Styrenesulfonate)/Single-Walled Carbon Nanotube/MXene Thermoelectric Composites and Their Devices

Despite the recent significant advancements of thermoelectric (TE) and TE generators (TEGs), the preparation of high-performance flexible films of organic/inorganic TE composites and the subsequent rational design of TEGs still remain a challenge. Here, the flexible films of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)/single-walled carbon nanotube/MXene (PEDOT:PSS/SWCNT/MXene) ternary composites were prepared by a pretreatment using ethylene glycol (EG), a vacuum filtration, and a subsequent posttreatment with dimethyl sulfoxide (DMSO). The composites exhibited a maximum room-temperature power factor (PF) of 162.15 ± 3.9 μW/(m·K²). Then, the TEGs with horizontal and vertical heat flow architectures were designed, and the effect of the number of TE legs was considered. Specifically, the vertically structured TEG-9pn prototype displayed a remarkably enhanced output power density of 474.87 μW/cm² under a temperature gradient of 60 K. Finally, the application scenarios of harvesting the heat from a beaker containing heat water and a hot plate were explored with both horizontal and vertical structure designs. Our work is beneficial to the preparation of flexible films of organic polymer TE composites and assembly of TEGs with versatile structural designs.