Facile synthesis of Cu7Te4 nanorods and the enhanced thermoelectric properties of Cu7Te4-Bi0.4Sb1.6Te3 nanocomposites

Nanocomposite thermoelectric (TE) materials have received great interest in recent years due to the large improvement in the figure of merit (ZT), which exceed the ZT approximate to 1 barrier. Herein, we report a facile method for the synthesis of surfactant-free Cu7Te4 using Te nanorods as templates, and the observed improvement of TE properties obtained by dispersing Cu7Te4 nanorods in a Bi0.4Sb1.6Te3 matrix. The matrix itself yields a maximum power factor of 2.45 mW/m K-2 at 300 K, while the addition of 5 wt% of Cu7Te4 nanorods increases and shifts the maximum power factor to 3.3 mW/m K-2 at 345 K. The maximum ZT obtained for the 5 wt% Cu7Te4-Bi0.4Sb1.6Te3 nanocomposite is 1.14 at 444 K, which is nearly 27% higher than the peak ZT achieved for the Bi0.4Sb1.6Te3 matrix. (C) 2012 Elsevier Ltd. All rights reserved.