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Ultralow Thermal Conductivity in Dual‐Doped n‐Type Bi 2 Te 3 Material for Enhanced Thermoelectric Properties
Author(s) -
Musah JamalDeen,
Guo Chen,
Novitskii Andrei,
Serhiienko Illia,
Adesina Ayotunde Emmanuel,
Khovaylo Vladimir,
Wu ChiMan Lawrence,
Zapien Juan Antonio,
Roy Vellaisamy A. L.
Publication year - 2021
Publication title -
advanced electronic materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.25
H-Index - 56
ISSN - 2199-160X
DOI - 10.1002/aelm.202000910
Subject(s) - materials science , seebeck coefficient , condensed matter physics , thermoelectric effect , thermal conductivity , thermoelectric materials , phonon scattering , doping , density of states , fermi level , bismuth , dopant , density functional theory , indium , electron , optoelectronics , thermodynamics , computational chemistry , chemistry , physics , composite material , quantum mechanics , metallurgy
Bismuth chalcogenides are promising materials for thermoelectric (TE) application due to their high power factor (product of the square of the Seebeck coefficient and electrical conductivity). However, their high thermal conductivity is an issue of concern. Single doping has proven to be useful in improving TE performance in recent years. Here, it is shown that dual isovalent doping shows the synergistic effect of thermal conductivity reduction and electron density control. The insertion of large atoms in the layered Bi 2 Te 3 structure distorts the crystal lattice and contributes significantly to phonon scattering. The ultralow thermal conductivity ( K T = 0.35 W m −1 K −1 at 473 K) compensates for the low power factor and thus enhances TE performance. The density functional theory electronic structure calculation results reveal deep defects states in the valence band, which influences the electronic transport properties of the system. Therefore, the dual dopants (indium and antimony) show a coupled effect of improvement in the density of state near the Fermi level and reduction in the conduction band minimum, thus enhancing electron density. Numerically, it is demonstrated that the dual doping favors acoustic phonon scattering and thus drastically reduces the thermal conductivity.