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

Résumé fourni par la source

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 Sb 6 O 13 nanoinclusions resulting from a displacement reaction between Sb and TeO 2 further suppresses thermal transport, leading to an ultra-low lattice thermal conductivity ( κ L ≈ 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%TeO 2 -1.8 wt%Sb sample. Our findings provide an effective approach to synergistically improve the thermal and electrical properties in advanced thermoelectric materials.

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