Thermoelectric Characteristics of Ultrathin Ag2Se Films with Durability Against Mechanical Stress

In this study, we investigated thermoelectric materials with durability against mechanical stress using Ag2Se nanoparticle (NP) thin films and colorless polyimide (CPI) substrates. Ag2Se NP thin films and CPI substrates were produced by spin-coating, and their thicknesses were 40 nm and 15 μm, respectively. A bendable thermoelectric film with a channel length of 40 μm and a channel area of 1.6 μm2 generated a Seebeck voltage of 1.43 mV at a temperature difference of 4.5 K. Owing to the thickness of the extremely thin thermoelectric film and substrate, the mechanical strain was only 0.15% even when the thermoelectric devices were bent with a curvature of 3 mm. Therefore, it was determined that the bendable thermoelectric film was robust against mechanical stress.