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From Dislocation to Nano‐Precipitation: Evolution to Low Thermal Conductivity and High Thermoelectric Performance in n ‐Type PbTe
Author(s) -
Deng PingYuan,
Wang KuangKuo,
Du JiaYu,
Wu HsinJay
Publication year - 2020
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.202005479
Subject(s) - materials science , thermoelectric effect , dislocation , phase diagram , precipitation , condensed matter physics , gallium , thermoelectric materials , doping , atmospheric temperature range , thermal conductivity , nanotechnology , thermodynamics , phase (matter) , optoelectronics , metallurgy , composite material , physics , meteorology , quantum mechanics
PbTe‐based alloys have been widely used as mid‐temperature thermoelectric (TE) materials since the 1960s. Years of endeavor spurred the tremendous advances in their TE performance. The breakthroughs for n ‐type PbTe have been somewhat less impressive, which limits the overall conversion efficiency of a PbTe‐based TE device. In light of this obstacle, an n ‐type Ga‐doped PbTe via an alternative thermodynamic route that relies on the equilibrium phase diagram and microstructural evolution is revisited. Herein, a plateau of zT = 1.2 is achieved in the best‐performing Ga 0.02 Pb 0.98 Te in the temperature range of 550–673 K. Notably, an extremely high average zT ave = 1.01 is obtained within 300 − 673 K. The addition of gallium optimizes the carrier concentration and boosts the power factor PF = S 2 ρ −1 . Meanwhile, the κ L of Ga‐PbTe reveals a significantly decreasing tendency owing to the defect evolution that changes from dislocation loop to nano‐precipitation with increasing Ga content. The pathway for both the κ L reduction and defect evolution can be probed by an equilibrium phase diagram, which opens up a new avenue for locating high zT TE materials.