Interface scattering induced low thermal conductivity in Ag2Se/MWCNT for enhanced thermoelectric application

Abstract

Ag2Se is a narrow bandgap semiconductor with an orthorhombic crystal structure at room temperature, resulting in an intrinsically low lattice thermal conductivity and large power factor, which is favourable for thermoelectric. In this work, we reported the improved thermoelectric properties of Ag2Se/MWCNTs nanocomposites synthesized by ultrasonication-assisted hydrothermal method followed by hot press densification technique. Here, MWCNTs act as scattering channels in the Ag2Se matrix to provide extra heat-carrying phonon scattering centres and reduced lattice thermal conductivity (κL) of 0.15 Wm−1 K−1 at 393 K. As a result, the maximum figure of merit (zT) of 0.73 at 393 K is achieved with better thermal stability. Our work provides a new concept to enhance thermoelectric properties through interface regulation.