Enhanced thermoelectric performance in polycrystalline N-type Pr-doped SnSe by hot forging

SnSe has attracted significant attention for use in thermoelectric devices due to its reported ultrahigh figureof-merit ZT in both p- and n-type single crystals, which inspired us to explore the thermoelectric properties of SnSe polycrystals for potential large-scale applications. Here, n-type Sn1-x PrxSe polycrystals are prepared by ball milling and hot pressing. A maximum ZT value of similar to 0.7 at 773 K is achieved in Sn0.97Pr0.03Se due to the enhanced electron concentration and electrical conductivity resulting from Pr doping at the Sn site. Through hot forging for a higher degree of orientation, a lowered thermal conductivity is obtained along the hotpressing direction, contributing to an enhanced ZT value of similar to 0.9 at 773 K in this direction. This study paves a new way for optimization of n-type SnSe by cation-site lanthanide doping. (C) 2020 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.