Manipulating Peierls-Nabarro stress to realize extraordinary thermoelectric performance in n-type PbTe

Abstract

PbTe is recognized as one of the best intermediate-temperature thermoelectric materials; however, its commercial applications are largely restricted by the comparatively lower performance of its n-type counterpart. Here we show that Peierls-Nabarro stress is manipulated through solute-induced lattice softening, which generates high density helical dislocations, dislocation loops, and subgrain boundaries to block heat transport phonons. Concurrently, in-situ formation of Sb6O13 nanoinclusions resulting from a displacement reaction between Sb and TeO2 further suppresses thermal transport, leading to an ultra-low lattice thermal conductivity (κL ≈ 0.21 W m−1 K−1 at 773 K). Moreover, Sb doping can simultaneously enhance electronic density of states, leading to the improvement of power factor (16 μW cm−1 K−2 at 563 K). As a result, a remarkably high figure of merit (ZT ≈ 2.2) is obtained at 723 K in n-type PbTe-1.5 wt%TeO2-1.8 wt%Sb sample. Our findings provide an effective approach to synergistically improve the thermal and electrical properties in advanced thermoelectric materials. The authors manipulated Peierls-Nabarro stress via solute-induced lattice softening to generate dense dislocations in n-type PbTe. Combined with Sb6O13 nanoinclusions, this sharply reduces thermal conductivity, yielding a peak ZT of 2.2 at 723 K.