Highly deformable Ag2Te1-xSex-based thermoelectric compounds
Liping Feng, Anan Guo, Keke Liu, Hui Bai, Jianan Lv, Qingjie Zhang, Jinsong Wu, Xianli Su, Xinfeng Tang, Ctirad Uher
Abstract
Thermoelectric semiconductors are crucial for many critical applications, but are also universally fragile, which greatly limits the development of room temperature flexible thermoelectric devices. Herein, an extraordinary deformability at room temperature and high thermoelectric performance are simultaneously realized in wide composition of Ag 2 Te 1-x Se x (x = 0–0.2) compounds with monoclinic structure. An average compressive strain rate of 24% at room temperature is attained for the pristine Ag 2 Te compound. Moreover, a tensile strain rate of 43% is measured at room temperature using the in-situ transmission electron microscopy . First Principles calculations and in-situ transmission electron microscope tensile test results indicate that the Ag 2 Te compound is inclined to slip along the (−102) [010] plane under external forces due to a larger ratio between the cleavage energy ( E c ) and the slip energy barrier. The slipping process generates high concentrations of dislocations, deformations, and amorphous structures, which together dissipate the externally applied load energy, yielding superior deformability. Meanwhile, the maximum dimensionless figure of merit ZT of 0.61 is obtained at 380 K. This study demonstrates that Ag 2 Te-based compounds are promising for the fabrication of flexible thermoelectric devices in applications, such as wearable, room temperature electronic gadgets.