Effect of solder and barrier layer elements on the thermoelectric properties of Bi_0.5Sb_1.5Te₃

Abstract

The interfacial diffusion between the electrode and thermoelectric legs is a key factor to determine thermoelectric (TE) module performance. Metal elements M (Sn, Ni, Ag, Cu) are frequently used in lead-free solder SAC serials and barrier layers. M’s effects on thermoelectric properties are investigated in this work, through doping 0.1 wt% M in Bi 0.5 Sb 1.5 Te 3 (BST) prepared by melting and spark plasma sintering method. The results show that the additive of Ag and Cu could enhance the average ZT value 69.4% and 75.5% in the temperature from 323 K to 573 K, and transfer ZT summit to 423 K, while Sn and Ni doping have little influence on the BST’s thermoelectric performance. The ZT peak value of Cu doped BST reaches 1.01 at 423 K, and Ag 0.96 at 423 K. This work exhibits a prospect that the efficiency of thermoelectric device can be improved by finely choosing different solders at cold and hot side of leg-electrode joint at different applied temperature.