Hierarchical Structures Lead To High Thermoelectric Performance In Cum+Npb100sbmte100se2m (Clast)

Ternary compound CuSbSe2-alloyed PbTe, CumPb100SbmTe100Se2m (CLAST), presents outstanding n-type thermoelectric transport behavior and features hierarchical Cu-based precipitates and interstitials that can balance phonon and carrier transport. Results show that a small amount of CuSbSe2 (similar to 3%) alloying in CLAST can realize a room-temperature carrier concentration of similar to 1.7 x 10(18) cm(-3) and then optimize the power factor, and simultaneously precipitate out embedded Cu-based nanostructures in the matrix to lower the lattice thermal conductivity. Additionally, extra Cu atoms adding in CLAST can form interstitials and further improve both the carrier concentration to similar to 3.0 x 10(18) cm(-3) and carrier mobility to similar to 1227.8 cm(2) V-1 s(-1) at room temperature, which benefits a maximum power factor of similar to 20.0 mu W cm(-1) K-2 in Cu3.3Pb100Sb3Te100Se6. Moreover, the Cu interstitials together with massive Cu-based nanoprecipitates can strongly scatter a wide set of phonons, and largely lower the lattice thermal conductivity to similar to 0.44 W m(-1) K-1 in Cu3.4Pb100Sb3Te100Se6 at 623 K. Finally, these Cu-based hierarchical structures in CLAST samples can synergistically optimize the phonon and carrier transport properties and contribute to a high ZT of similar to 0.5 at 300 K and a peak ZT of similar to 1.4 at 723 K. A remarkably high ZT(ave) of similar to 0.94 at 300-723 K is achieved in Cu3.3Pb100Sb3Te100Se6 due to high ZT values in the low temperature range, outperforming other high-performance n-type PbTe-based thermoelectric materials.