2020 Volume 63 Issue 5 Pages 239-244
The thermoelectric generator (TEG) is expected to be an energy harvester for the supply of electricity to wearable or Internet-of-Things devices. For this purpose, organic-based thermoelectric materials have been extensively studied. In this report, the results of a survey study on organic-based thermoelectric materials by the author's group are presented, and two novel and interesting material groups introduced. The first is a group of pure organic semiconductors. Giant Seebeck coefficients (＞0.1 V/K) are found to appear in such materials near room temperature. Owing to the extremely large Seebeck coefficient, the device structure can be ultimately simple without connecting many p/n semiconductor blocks as in conventional TEGs. The second is a group containing two different material phases, such as carbon nanotube (CNT) composites. They are suitable for fabric-type TEGs. A key issue is how to suppress their high thermal conductivity. A protein molecular junction is used to suppress the phonon propagation while maintaining the electron transport.