High Thermoelectric Properties of n-Type AgBiSe_2

摘要

We report on the thermoelectric (TE) performance of intrinsic n-type AgBiSe_2, a Pb-free material with more earth-abundant and cheaper elements than intrinsic p-type homologous AgSbTe_2. Pb doping changes n-type AgBiSe_2 to p-type but leads to poor electrical transport properties. Nb doping enhances the TE properties of n-type AgBiSe_2 by increasing the carrier concentration. As a result of the intrinsically low thermal conductivity (0.7 W m~(-1) K~(-1)), low electrical resistivity (5.2 mΩ cm), and high absolute Seebeck coefficient (-218 μV/K), the TE figure of merit (ZT) at 773 K is significantly increased from 0.5 for solid-state-synthesized pristine AgBiSe_2 to 1 for Ag_(0.96)Nb_(0.04)BiSe_2, which makes it a promising n-type candidate for medium-temperature TE applications.