Fabrication and Excellent Performances of Bismuth Telluride-Based Thermoelectric Devices

The barrier layer between thermoelectric (TE) legs and electrodes has crucial impact on the electrothermal conversion efficiency of the TE device; however, the interfacial reaction of the Ni metal barrier layer with TE legs in traditional Bi₂Te₃-based devices is harmful to the device performance. Herein, a high-quality barrier layer of a Ni-based alloy has been fabricated on both n-type and p-type Bi₂Te₃-based TE legs by the electroplating method. The in situ XRD results indicate that the as-prepared Bi₂Te₃-based TE legs with a Ni-based alloy barrier layer remain stable even at 300 °C. The high-resolution high-angle annular dark field scanning transmission electron microscopy images reveal that the Ni-based alloy barrier layer has more excellent stability than that of the Ni metal barrier layer. The Bi₂Te₃-based TE devices with excellent structural and performance stabilities were assembled with the as-grown high-performance n-type and p-type Bi₂Te₃-based leg with a Ni-based alloy barrier layer, which have lower internal resistance and higher cooling and power generation performances. A maximum cooling temperature difference over 65 K and a maximum cooling capacity of 55 W were obtained for the high-performance Bi₂Te₃-based TE devices. This work provides a new strategy for high-temperature applications of commercial Bi₂Te₃-based TE devices.