Recently, Prof. Qin Xiaoying¡¯s group from Institute of Solid State physics, Hefei Institutes of Physical Science has proposed a simple method for preparing ¦Â-Ag2Se based materials.
Thermoelectric (TE) materials open up possibilities for waste heat recovery and cooling applications. The performance of thermoelectric materials is determined by the value ZT=¦ÒS2T/, where ¦Ò, S, T and are conductivity, Seebeck coefficient, absolute temperature and thermal conductivity, respectively.
Therefore, materials with high ZT require high power factor (PF=¦ÒS2) and low thermal conductivity. Different preparation methods have a great impact on the ZT value of ¦Â-Ag2Se. The peak ZT of ¦Â-Ag2Se prepared by smelting method at room temperature is 0.32~0.96, while the maximum ZT of ¦Â-Ag2Se prepared by wet chemistry method is only 0.23, which severely limits the application of ¦Â-Ag2Se nanocrystalline.
In this end, the team successfully synthesized ¦Â-Ag2Se and ¦Â-Ag1.9Sn0.1Se nano-crystalline material by one-step method. Repeated tests on samples of ¦Â-Ag2Se showed that the material properties were stable and the maximum ZT of ¦Â-Ag2Se was 0.7.
Further, Sn doping was used to improve the electrical and thermal properties of ¦Â-Ag2Se and the thermoelectric performance of ¦Â-Ag2Se by partially replacing Ag with Sn.
The research results showed that the peak value of ¦Â-Ag1.9Sn0.1Se reached0.9 at 300K, which was similar to that of Bi2Te2.7Se0.3, the only n-type thermoelectric material used at room temperature, and was the highest value reported by wet chemical method.
The related work also provides technical guidance for optimizing the performance of other thermoelectric materials.
The work was supported by the national natural science foundation of China and by the funding support from the Natural Science Foundation of China.
link to the paper: High thermoelectric performance for an Ag2Se-based material prepared by a wet chemical method
Fig. 1 Thermoelectric properties as a function of temperature for Ag2-xSnxSe (x = 0 and 0.1): (a)¦Ñ; (b) S; (c) PF; (d)¦Ê; (e) ZT and (f) comparison of ZT with the value reported. (Image by CHEN Tao)