Attempts to realize promising thermoelectric performance in n-type polycrystal SnSe with cubic structure

Abstract

Both crystal and polycrystal p-type SnSe have been investigated with promising thermoelectric capabilities across a broad temperature range, garnering significant attention recently. However, the inferior electrical transport of n-type polycrystal SnSe especially at low temperatures have seriously restricted the advancement of thermoelectric devices based on SnSe. In the study, we attempted to attain promising thermoelectric properties of n-type polycrystal SnSe through modulating the lattice structure by AgBiSe2 alloying. After subsequent Br doping and Pb alloying, n-type polycrystal SnSe with cubic structure exhibited completely reversed electrical transport especially at low temperatures (300-600 K). Resultantly, the polycrystal (Sn0.6Pb0.4Se0.97Br0.03)0.6(AgBiSe2)0.4 demonstrated promising thermoelectric properties, achieving the maximum ZT value of roughly 0.3 under 600 K, outperforming the performance of most other current n-type SnSe polycrystals. Our research presents a systematic method for obtaining n-type SnSe with cubic-phase structure and promising performance, laying a basic foundation for constructing high-efficiency all-SnSe-based homogeneous thermoelectric devices.