Improved Thermoelectric Performance of P-type SnTe through Synergistic Engineering of Electronic and Phonon Transports

SnTe has been regarded as a potential alternative to PbTe in thermoelectrics because of its environmentally friendly features. However, it is a challenge to optimize its thermoelectric (TE) performance as it has an inherent high hole concentration (n(H)similar to 2 x 10(20) cm(-3)) and low mobility (mu(H)similar to 18 cm(2) V-1 s(-1)) at room temperature (RT), arising from a high intrinsic Sn vacancy concentration and large energy separation between its light and heavy valence bands. Therefore, its TE figure of merit is only 0.38 at similar to 900 K. Herein, both the electronic and phonon transports of SnTe were engineered by alloying species Ag0.5Bi0.5Se and ZnO in succession, thus increasing the Seebeck coefficient and, at the same time, reducing the thermal conductivity. As a result, the TE performance improves significantly with the peak ZT value of similar to 1.2 at similar to 870 K for the sample (SnGe0.03Te)(0.9)(Ag0.5Bi0.5Se) 0.1 + 1.0 wt % ZnO. This result proves that synergistic engineering of the electronic and phonon transports in SnTe is a good approach to improve its TE performance.

Automated summary

By alloying with Ag0.5Bi0.5Se and ZnO sequentially, both the electronic and phonon transports of SnTe were engineered to increase the Seebeck coefficient and reduce thermal conductivity. This synergistic engineering led to a significant improvement in TE performance with a peak ZT value of about 1.2 at around 870 K for the sample.