Affiliation:
1. Institutes of physical Science and Information Technology Anhui University Hefei 230601 P. R. China
2. Key Lab of Photovoltaic and Energy Conservation Materials Institute of Solid State Physics HFIPS Chinese Academy of Sciences Hefei 230031 P. R. China
3. University of Science and Technology of China Hefei 230026 P. R. China
Abstract
AbstractMaterials with low intrinsic lattice thermal conductivity are crucial in the pursuit of high‐performance thermoelectric (TE) materials. Here, the TE properties of PbBi2Te4‐xSex (0 ≤ x ≤ 0.6) samples are systematically investigated for the first time. Doping with Se in PbBi2Te4 can simultaneously reduce carrier concentration and increase carrier mobility. The Seebeck coefficient is significantly increased by doping with Se, based on the density functional theory calculation, it is shown to be due to the increased bandgap and electronic density of states. In addition, the lattice strain is enhanced due to the difference in the size of Se and Te atoms, and the multidimensional defects formed by Se doping, such as vacancies, dislocations, and grain boundaries, enhance the phonon scattering and reduce the lattice thermal conductivity by about 37%. Finally, by using Se doping to reduce carrier concentration and thermal conductivity, a large ZTmax = 0.56 (at 574K) is achieved for PbBi2Te3.5Se0.5, which is around 64% larger than those of the PbBi2Te4 pristine sample. This work not only demonstrates that PbBi2Te4 is a potential medium temperature thermoelectric material, but also provides a reference for enhancing thermoelectric properties through defect and energy band engineering.
Funder
National Natural Science Foundation of China
Natural Science Foundation of Anhui Province
Cited by
1 articles.
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