Remarkable Roles of Cu To Synergistically Optimize Phonon and Carrier Transport in n-Type PbTe-Cu₂Te

Abstract

High thermoelectric performance of n-type PbTe is urgently needed to match its p-type counterpart. Here, we show a peak ZT ∼ 1.5 at 723 K and a record high average ZT > 1.0 at 300-873 K realized in n-type PbTe by synergistically suppressing lattice thermal conductivity and enhancing carrier mobility by introducing CuTe inclusions. Cu performs several outstanding roles: Cu atoms fill the Pb vacancies and improve carrier mobility, contributing to an unexpectedly high power factor of ∼37 μW cm K at 423 K; Cu atoms filling Pb vacancies and Cu interstitials both induce local disorder and, together with nano- and microscale Cu-rich precipitates and their related strain fields, lead to a very low lattice thermal conductivity of ∼0.38 Wm K in PbTe-5.5%CuTe, approaching the theoretical minimum value of ∼0.36 Wm K. This work provides an effective strategy to enhance thermoelectric performance by simultaneously improving electrical and thermal transport properties.

Cu Intercalation and Br Doping to Thermoelectric SnSe2 Lead to Ultrahigh Electron Mobility and Temperature‐Independent Power Factor

“…[13] The latter is directly determined by the product S 2 σ, so called the power factor (PF). [16][17][18][19][20][21][22] Recently, PbSe-based TE materials have also been greatly improved with new innovative strategies. When abundant heat is supplied at low cost, TE modules with high PF materials could be more commercially viable at present because they can consistently produce a large output power density under the given temperature gradient.…”

The Atomic Circus: Small Electron Beams Spotlight Advanced Materials Down to the Atomic Scale

“…Thermoelectricity enables the direct interconversion between electrical and thermal energy, useful for recycling electric power from sources of waste heat and for solid‐state refrigeration of electronic devices. Structural defects at various scales strongly affect both the thermal and electrical transport properties . The electrical transport properties (Seebeck coefficient and electrical conductivity) of a thermoelectric material are dominated by its electronic band structure and the interaction of charge carriers with structural defects at varying scales .…”

“…Structural defects at various scales strongly affect both the thermal and electrical transport properties . The electrical transport properties (Seebeck coefficient and electrical conductivity) of a thermoelectric material are dominated by its electronic band structure and the interaction of charge carriers with structural defects at varying scales . The total relaxation time for the lattice thermal conductivity is an integration of various scattering processes, including intrinsic Umklapp and normal processes, and extrinsic processes related to structural imperfections from the microscale to the atomic level …”

Comprehensive Investigation on the Thermoelectric Properties of p‐Type PbTe‐PbSe‐PbS Alloys

“…[9,[20][21][22] Besides, the intrinsic lattice thermal conductivities of lead chalcogenides are quite low due to the phonon anharmonicity. [23][24][25] In the past few years, several approaches have been employed to enhance the thermoelectric performance of lead chalcogenides, such as enhancing electrical properties through introducing resonant states [8,26,27] and manipulating band structures, [28] suppressing thermal conductivities through introducing nanostructures, [25,[29][30][31][32] and all-scale hierarchical structures. [23][24][25] In the past few years, several approaches have been employed to enhance the thermoelectric performance of lead chalcogenides, such as enhancing electrical properties through introducing resonant states [8,26,27] and manipulating band structures, [28] suppressing thermal conductivities through introducing nanostructures, [25,[29][30][31][32] and all-scale hierarchical structures.…”