Energy turnaround: Printing of thermoelectric generators

Waste heat in the temperature range up to 100 °C can be found in virtually all areas of industry and building and is often the hardest to recover cost-efficiently. It accounts for more than 50 % of the total heat generated in industry [1]. Therefore, increasing interest is noticed in thermoelectric harvesters in the operation temperature range from room temperature up to 100 °C. The aim of this work is the development of materials and processes for the material and cost efficient scalable production of TEGs. PEDOT:PSS is an interesting p-type conducting polymer suitable for printing of TEGs. A printed unileg generator, i.e. by using just a p-conductive material, was realised by dispenser printing of DMSO-doped PEDOT:PSS on polyimide. Contacts were made from silver. A TEG with 60 legs was characterized. The internal resistance is increasing linearly with the number of legs, confirming the good reproducibility of the printing process. By using a multilayer design the resistance can be decreased by more than 50 %. A temperature difference of 90 K results in a voltage of 37 mV (at 20 °C at the cold side).