Anisotropic electrical transports in rolled Ag2Se film

Ag2Se is a promising room-temperature thermoelectric (TE) material that can be processed into free-standing films by using the hot-rolling method. In this work, we find the rolled Ag2Se film has anisotropic electrical transport. The carrier mobility, electrical conductivity, and power factor parallel to the rolling direction are much higher than those perpendicular to the rolling direction. Such anisotropic electrical transports originate from the grain elongation during the rolling process, which introduces more grain boundaries perpendicular to the rolling direction to scatter carriers. This work is meaningful for using the rolled Ag2Se film to fabricate the high-performance flexible TE devices.