Influence of Ag doping on the thermoelectric properties of layered compound NdOZnSb

Abstract

Quaternary layered compound NdOZnSb is viewed as a thermoelectric candidate owing to the stacked building blocks, e.g. conductive [ZnSb] layer and insulting [NdO] layer featuring narrow band-gap semiconductor behavior. However, the measured figure of merit ZT is quite low for pristine NdOZnSb resulted from poor electrical conductivity despite considerable Seebeck coefficient and low thermal conductivity. The present paper demonstrates that Ag doping can precisely tune the electrical transport properties and accordingly enhance the power factor. The electrical conductivity of NdOZnSb increases by an order of magnitude at 325K via the substitution of Zn by Ag, and the maximal thermoelectric figure of merit ZT for NdOZn0.96Ag0.04Sb reaches 0.44 at 725K.