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

摘要

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 Sn0.97Na0.03Se. 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 (approximate to 6.01 W cm(-1) K-2) and ZT (approximate to 0.45) from 300 to 830 K are achieved. A maximum ZT value of 0.8 at 830 K is obtained in Sn 0.97Na0.03Se with 5 wt% additional Te.