| dc.description.abstract | Thermoelectric materials can directly realize the mutual conversion between heat and electricity by the movement of internal carriers and have huge application prospects in the fields of factory waste heat power generation, solid-state refrigeration, and human body wearable devices. Organic thermoelectric materials have unique advantages of lightness, non-toxicity, high mechanical flexibility, low thermal conductivity and easy industrial large-scale preparation. Among the organic materials currently studied, poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) can be dispersed in water easily, and the film formed has great mechanical properties. However, the original PEDOT:PSS film has poor thermoelectric performance which the electrical conductivity is generally lower than 1 S cm-1, and Seebeck coefficient is only about 11-17 µV K-1. Therefore, it is necessary to modify its thermoelectric performance. In this paper, the PEDOT:PSS system is doped with ionic liquid which carry binary charges to increase the conductivity and Seebeck coefficient at the same time. Simultaneously, to compare the influence of the improvement of thermoelectric properties of PEDOT:PSS films by cations with different alkyl side chain lengths, we used 1,3-dimethylimidazole (MMIM+), 1-Ethyl-3-methylimidazolium (EMIM+), 1-Butyl-3-methylimidazole (BMIM+), 1-Hexyl-3-methyl imidazole (HMIM+) cation of tetrafluoroborate (BF4-). When using 2 mol L-1 MIMM BF4 methanol solution to post-process the PEDOT:PSS thermoelectric film, the Seebeck of the film can be increased to 24.4 μV K-1, and the electrical conductivity increased to 1447.3 S cm-1, and the power factor value is increased to 86.34 μW m-1K-2. Then, using the Marangoni force-assisted method to spread micrometer-thick polymer films transferring to the surface of the special-shaped structure and make a flexible thermoelectric wristband. At a temperature difference of 25 K, a thermal power of 10.4 nW was obtained and the power density was 0.165 W m-2. | en_US |