Combination of electrodeposition and transfer processes for flexible thin-film thermoelectric generators

Abstract

To reduce consumption for ambient assisted living (AAL) applications, we propose the design and fabrication of flexible thin-film thermoelectric generators at a low manufacturing cost. The generators were fabricated using a combination of electrodeposition and transfer processes. N-type Bi2Te3 films and p-type Sb2Te3 films were formed on a stainless-steel substrate employing potentiostatic electrodeposition using a nitric acid-based bath, followed by a transfer process. Three types of flexible thin-film thermoelectric generators were fabricated. The open circuit voltage (Voc) and maximum output power (Pmax) were measured by applying a temperature difference between the ends of the generator. The thin-film generators obtained using thermoplastic sheets with epoxy resin exhibited a Voc that was tens of millivolts. In particular, the contact resistance of the thin-film generator decreased when silver paste was inserted at the junctions between the n- and p-type films. The most flexible thin-film generator fabricated in this study exhibited a Pmax of 10.4 nW at a temperature difference of 60 K. The current performance of the generators was too low, but we innovated a combination process to prepare them. It is expected to increase the performance by further decreasing the micro-cracks and contact resistance in the generators.