Rare-Earth Nd Inducing Record-High Thermoelectric Performance of (GeTe)85(AgSbTe2)15

As a promising midtemperature thermoelectric material with both higher thermoelectric performance and mechanical property, Tellurium Antimony Germanium Silver (TAGS-x), written as (GeTe)(x)(AgSbTe2)(1-x), especially (GeTe)(0.85)(AgSbTe2)(0.15) (TAGS-85), has attracted wide attention. Herein, we innovatively use Nd doping to synergistically decrease the carrier concentration to the optimal level leading to enhanced dimensionless figure of merit, zT. Our density-functional theory calculation results indicate that Nd-doping reduced carrier concentration should be attributed to the enlargement of band gap. The optimized carrier concentration results in an ultrahigh power factor of similar to 32 mu Wcm(-1) K-2 at 727 K in Ge0.74Ag0.13Sb0.11Nd0.02Te. Simultaneously, the lattice thermal conductivity of Ge0.74Ag0.13Sb0.11Nd0.02Te retained as low as similar to 0.5 at 727 K. Ultimately, a record-high zT of 1.65 at 727 K is observed in the Ge0.74Ag0.13Sb0.11Nd0.02Te. This study indicates rare-earth Nd doping is effective in boosting the thermoelectric performance of TAGS-85 and approached a record-high level via synergistic effect.

Automated summary

By doping rare-earth Nd, the carrier concentration in TAGS-85 was optimized, leading to an enhanced zT value and achieving a record-high thermoelectric performance at 727 K.