Electrochemical assembly of flexible PPy/Bi–Te alloy/PPy thermoelectric composite films with a sandwich-type structure

Organic–inorganic thermoelectric (TE) nanocomposites, which can make up for the deficiency of both, are expected to achieve better TE performance than their individual counterparts. In this study, electrochemical assembly is carried out to fabricate a series of TE composites with an innovative sandwich structure. By electrochemical assembly, polypyrrole (PPy), the Bi–Te alloy and PPy are deposited successively on a stainless steel (SS) electrode, and a PPy/Bi–Te/PPy structured flexible nanocomposite film is obtained after peeling from the SS electrode. Through the regulation of the current density for Bi–Te electrodeposition and the time for PPy electrodeposition, the optimal composite film harvested a largest power factor of 244 ± 6 μW m−1 K−2, which exceeds that of most of the composite TE materials obtained from electrodeposition. Moreover, its TE performance was further verified by making it into a flexible thermoelectric generator (F-TEG). This work provides a new way for the construction of organic–inorganic composite TE materials, and promotes the application of flexible wearable TE devices.