Influence of Nanoscale Ag2Te Precipitates on the Thermoelectric Properties of the Sn Doped P-Type AgSbTe2 Compound
Rajeshkumar Mohanraman1,2,3*, Chih Hao Lee1, Yang-Yuan Chen3
1Department of Engineering and System Science, National Tsing Hua University, Hsinchu, Taiwan
2Nano Science and Technology, Taiwan International Graduate Program, Institute of Physics,, Academia Sinica and National Tsing Hua University, Taipei, Taiwan
3Institute of Physics, Academia Sinica, Taipei, Taiwan
* presenting author:RAJESHKUMAR MOHANRAMAN, email:rajeshx1983@gmail.com
We report a maximal figure of merit (ZT) value of 1.1 at 600 K was obtained for the sample of which x = 0.03, representing an enhancement greater than 20% compared with a pristine AgSbTe2 sample. This favorable thermoelectric performance originated from the optimal Sn2+ substitution for Sb3+ in AgSbTe2, which not only increased electrical conductivity but also led to a substantial reduction in thermal conductivity that was likely caused by an enhanced phonon-scattering mechanism through the combined effects of lattice defects and the presence of Ag2Te nanoprecipitates dispersed in the matrix.

The main finding of this investigation is that doping an Ag(Sb1-xSnx)Te2 system with an optimal amount of Sn (x = 0.03) is the most effective method for controlling the morphology and size of nanoprecipitates and achieving high ZT values, and that doping the system with amounts substantially higher than the optimal amount yields adverse effects.


Keywords: thermoelectric, AgSbTe2, tin doping, nanoprecipitates, lattice thermal conductivity