Recently, Prof. ZHANG Yongsheng's research group at Institute of Solid State Physics under Hefei Institutes of Physical Science has successfully screened some new promising thermoelectric materials from all binary chalcogenides through high-throughput (HT) computations.
Searching for new promising thermoelectric (TE) materials is one of the most important methods to facilitate the global commercialization of TE devices. To HT calculate the TE properties of materials, the electrical and phonon properties need to be evaluated efficiently.
However, due to the complexity and difficulty to calculate the electron-phonon scattering and anharmonicity, two oversimplified approximations were used in many previous HT TE computations. One is to use the constant carrier relaxation time for the electrical properties, the other is to omit the anharmonicity.
To improve the accuracy in the HT TE computations, based on the deformation potential and elastic properties methods, the group established two efficient descriptors to characterize the electrical properties (power factor) and the lattice thermal conductivity.
Meanwhile, they wrote a thermoelectric HT computation code, named ThermoElectric Material Genome (TEMG), to automatically convert the geometric structures of compounds in the database into the VASP input structure files, prepare VASP-DFT input parameters, submit DFT calculation jobs, collect DFT calculated results and analyze the TE properties of materials, etc.
Based on the works that have been done, they HT calculated the TE properties of all 243 binary semiconductor chalcogenides and successfully screened 50 promising TE materials.
These theoretically determined compounds include some promising TE materials that have been experimentally and theoretically investigated previously, which could verify the validity of their prediction methods.
Additionally, some previously unreported binary chalcogenides are predicted as the new high-performance TE materials.
Furthermore, based on the relationship between the TE properties and the geometry space groups and stoichiometries, the group established the simple criteria for the high-performance TE materials.
Their work provided not only new TE candidates with perfect crystalline structure for the future investigations but also reliable descriptors and judgment criteria to HT screen high-performance TE materials.
The research was supported by the National Natural Science Foundation of China.
The flowchart of the high-throughput research. (Image by ZHANG Yongsheng)
Screened promising thermoelectric materials within the 243 binary semiconductor chalcogenides using the Grüneisen parameter and the electrical descriptor. The black and red spheres represent the theoretically predicted promising thermoelectric materials for p-type and n-type doping, respectively. (Image by JIA Tiantian)
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