Improved Thermoelectric Performance in Ga‐ and Te‐Co‐introduced Tetrahedrite Cu 12 Sb 4 S 13

As an earth‐abundant, environment‐friendly, and cost‐effective material, tetrahedrite Cu 12 Sb 4 S 13 has attracted much attention in thermoelectrics (TEs). However, the TE performance of the pristine Cu 12 Sb 4 S 13 (CSS) is mediocre, thereby much improvement is required. In this work, both the electronic and phonon transports of the CSS are engineered using Ga 2 Te 3 as a dopant. In the results, it is indicated that dual substitutions of Ga for Cu and Te for Sb not only cause the enhancement of power factor via electronic band structure tuning, but also leads to a drop in both the electronic and lattice thermal conductivities. As a result, the total thermal conductivity ( κ ) decreases to 0.98 W m −1 K −1 at 770 K, which is about 58% that of the pristine CSS, thus improving the TE performance with the highest dimensionless figure of merit value increasing to 0.95 for (Cu 12 Sb 4 S 13 ) 0.9 (Ga 2 Te 3 ) 0.1 at 773 K, 1.9 times that of the pristine CSS (≈0.5 at 770 K).