Fabrication and Excellent Performances of Bismuth Telluride-Based Thermoelectric Devices
Wu Zhu, Ping Wei, Jianqiang Zhang, Longzhou Li, Wanting Zhu, Xiaolei Nie, Xiahan Sang, Qingjie Zhang, Wenyu Zhao
Abstract
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.