Journal
SMALL
Volume 18, Issue 23, Pages -Publisher
WILEY-V C H VERLAG GMBH
DOI: 10.1002/smll.202201352
Keywords
bismuth telluride; conversion efficiency; mechanical properties; point defect reconfiguration; thermoelectric performance
Categories
Funding
- National Natural Science Foundation of China [52130106, 52101247, 51871082]
- Natural Science Foundation of Heilongjiang Provence of China [2020E003]
- Heilongjiang Touyan Innovation Team Program
- Fundamental Research Funds for the Central Universities [FRFCU5710053021, HIT.OCEF.2021014]
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In this work, the thermoelectric and mechanical properties of n-type Bi2Te3 alloy were enhanced by point defect configuration using S/Te/I defects engineering. When combined with p-type BiSbTe, the fabricated module showed competitive conversion efficiency. The work revealed a novel mechanism of point defect reconfiguration in synergistic enhancement of thermoelectric and mechanical properties, which may be applicable to other thermoelectric systems.
Bi2Te3-related alloys dominate the commercial thermoelectric market, but the layered crystal structure leads to the dissociation and intrinsic brittle fracture, especially for single crystals that may worsen the practical efficiency. In this work, point defect configuration by S/Te/I defects engineering is engaged to boost thermoelectric and mechanical properties of n-type Bi2Te3 alloy, which, coupled with p-type BiSbTe, shows a competitive conversion efficiency for the fabricated module. First, as S alloying suppresses the intrinsic BiTe, antisite defects and forms a donor-like effect, electronic transport properties are optimized, associated with the decreased thermal conductivity due to the point defect scattering. The periodide compound TeI4 is afterward adopted to further tune carrier concentration for the realization of an optimal ZT. Finally, an advanced average ZT of 1.05 with ultra-high compressive strength of 230 MPa is achieved for Bi2Te2.9S0.1(TeI4)(0.0012). Based on this optimum composition, a fabricated 17-pair module demonstrates a maximum conversion efficiency of 5.37% under the temperature difference of 250 K, rivaling the current state-of-the-art Bi2Te3 modules. This work reveals the novel mechanism of point defect reconfiguration in synergistic enhancement of thermoelectric and mechanical properties for durably commercial application, which may be applicable to other thermoelectric systems.
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