Optimized orientation and enhanced thermoelectric performance in Sn0.97Na0.03Se with Te addition

Abstract

Na doped SnSe shows excellent electronic properties and ultralow thermal conductivity, leading to a record high ZT value in its single crystal. Owing to weak orientation, polycrystalline SnSe shows a lower electrical conductivity and power factor. In this work, additional Te is introduced in the process of sample preparation to increase the orientation of polycrystalline Sn_0.97Na_0.03Se. The orientation obviously improves with the increase of Te amount, leading to a great improvement of the electronic properties, especially in the low temperature region. An enhanced averaged power factor (∼6.01 μW cm⁻¹ K⁻²) and ZT (∼0.45) from 300 to 830 K are achieved. A maximum ZT value of 0.8 at 830 K is obtained in Sn _0.97Na_0.03Se with 5 wt% additional Te.