Japanese researchers develop low-cost thermoelectric thin films

April 26, 2016 // By Julien Happich
NEC, NEC Tokin and Tohoku University have co-developed a thin-film spin Seebeck thermoelectric device which they hope could be cheaply produced at low temperature onto large sheets to wrap around industrial waste heat sources.

Thanks to new materials and a new device structure, the Japanese researchers claim a conversion efficiency more than 10 times higher than prior art relying on the spin Seebeck thermoelectric effect.

Published in Scientific Reports under the title "Flexible heat-flow sensing sheets based on the longitudinal spin Seebeck effect using one-dimensional spin-current conducting films", the paper discloses a ferrite plating method, growing a 1μm-thick Ni0.2Zn0.3Fe2.5O4 ferromagnetic film on a 25μm-thick polyimide substrate at a process temperature of 90°C.

Not only the process is achieved at much lower temperatures than competing solutions (they mention 700°C for conventional methods), but they rely on an aqueous reaction of two solutions, (FeCl2 + NiCl2 + ZnCl2) and an oxidizer (NaNO2 + CH3COONH4) spread on a plastic film through two nozzles, making the process relatively easy to scale up on large sheets of plastic films or even across various shapes.