Fabrication and characterization of roll-type thin-film thermoelectric generators

Abstract

We propose and demonstrate a facile fabrication method of roll-type thin-film thermoelectric generators to conveniently use a low electric power converted from ambient heat sources. The generators consisted of n-type Bi2Te3 and p-type Sb2Te3 thin films, which were deposited on a polyimide sheet by radio-frequency magnetron sputtering. Both types of thin films were thermally annealed to increase the thermoelectric properties. The annealed thin films were connected to each other using silver paste, with the p-n junctions connected electrically in series. The completed generator consisted of five p-n pairs was 625 mm long and 26 mm wide. To form the roll-type structure, the generator was bent so that the fold lines were located at the p-n junctions. The performance of the generators, such as the open circuit voltage (Voc) and maximum output power (Pmax), were measured by applying a temperature difference (ΔT) between the ends of the generator. As a result, the generator exhibited a Voc of 20.1 mV and a Pmax of 48.5 nW at a ΔT of 30 K. In addition, we calculated the performances of generators with different film thickness or number of p-n pairs based on the experimental results.