Optimizing output performances in stationery papers-based hybrid inorganic-organic flexible thermoelectric generators

Flexible and foldable paper-based thermoelectric generators (PTEGs) have drawn industrial attention due to the wide applications in heat energy harvesting and sensing. Herein, optimization of the output performances of flexible and hybrid inorganic-organic PTEGs fabricated on stationery paper substrates from poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) and graphite as p-type and n-type materials, respectively, is presented. By choosing simplistic processes such as polyethyleneimine (PEI)-treated graphite pencil traces and brush-painted PEDOT:PSS films, robust and sustainable PTEG devices are fabricated. It is first time shown that different qualities of stationery papers can have significant impact on the output performance of PTEGs, attributed to their variance in substrate roughness. Thus, output powers of ≈1.93 and ≈0.68 nW for $\Delta$T = 70 K are obtained for TE generators prepared from emery and office paper legs (four-pair assembled on Kapton), respectively, suggesting emery paper to have significant better performance. Transient flexibility and fatigue of each device type are also tested where emery paper-based PTEG appears to be more robust. A detail comparison of the device performances on the different types of paper substrates are exclusively presented experimentally and thereafter computationally validated by COMSOL modeling to predictably control and enhance the output performance of reported PTEGs. (© 2023 Wiley‐VCH GmbH)