Influence of Preparation Processes on the Structure and Properties of the Ductile Thermoelectric Material Ag2S0.4Te0.6
Authors: LIU Jinxiao, LIU Zhenhan, CHEN Xingyu, ZHOU Zhengyang, QIU Pengfei, ZHANG Jiawei, SHI Xun
Ag2S0.4Te0.6 is an inorganic semiconductor with favorable ductility and thermoelectric performance, showing potential for applications in wearable electronics. Recent studies have indicated that optimization of preparation processes, such as annealing, can significantly enhance the ductility of the material, which is closely related to its phase composition and crystal structure. In this work, high-resolution synchrotron radiation powder X-ray diffraction data of the Ag2S0.4Te0.6 powder sample before and after annealing were collected over a temperature range of 110–700 K. By combining Rietveld structural refinement, high-resolution transmission electron microscopy, and atomic pair distribution function analysis, the influence of the annealing process on the phase composition and structural evolution behavior of the powder samples was investigated in detail. The results show that the pristine Ag2S0.4Te0.6 powder is predominantly amorphous, containing only a small amount of poorly crystalline monoclinic phase. During heating, the material gradually crystallizes, first forming a monoclinic phase, which subsequently transforms into mixed body-centered cubic (bcc) and face-centered cubic (fcc) phases. After cooling back to room temperature, the sample remains in a mixed state of bcc-dominated cubic crystallinity and amorphous phase. In contrast, the annealed powder sample already exhibits a mixed cubic crystalline/amorphous state at room temperature, and no obvious phase transition behavior is observed during heating. Moreover, the thermoelectric properties of Ag2S0.4Te0.6 bulk sample remain largely unaffected by the annealing process. This study provides structural insights for further understanding the annealing-induced improvement in ductility.
