1. Thermoelectric properties of non-stoichiometric Cu2+xSn1−xS3 compounds.
- Author
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Deng, Tingting, Qiu, Pengfei, Song, Qingfeng, Chen, Hongyi, Wei, Tian-Ran, Xi, Lili, Shi, Xun, and Chen, Lidong
- Subjects
THERMAL conductivity ,NONSTOICHIOMETRIC compounds ,TETRAHEDRA ,CARRIER density ,SEEBECK coefficient ,VALENCE bands - Abstract
Diamondlike compound Cu
2 SnS3 has attracted great attention recently due to its excellent thermoelectric performance and the features of being eco-friendly and low cost. However, the underlying mechanism for its good electrical transports under high carrier concentration range is still not clear. In this work, we synthesized a series of Cu2+x Sn1− x S3 (x = 0–0.08) samples. These nonstoichiometric Cu2+x Sn1− x S3 samples are polymorph simultaneously crystalizing in the monoclinic, tetragonal, and cubic structures. The characterization on the electrical transports and the analysis on the band structure reveal that the large density-of-states effective mass, high Seebeck coefficient, and high mobility under a high carrier concentration in the Cu2+x Sn1− x S3 system are originated from the existence of multiple bands near the edge of the valence band. Likewise, the polymorphic structure has little influence on the electrical transports. A maximum power factor of 12.6 μW cm−1 K−2 at 700 K has been obtained for the nonstoichiometric Cu2.08 Sn0.92 S3 . Combining the low lattice thermal conductivity of these samples, Cu2.08 Sn0.92 S3 shows a peak dimensionless figure of merit of 0.5 at 700 K. This work is helpful for guiding the future optimization of thermoelectric performance on Cu2 SnS3 . [ABSTRACT FROM AUTHOR]- Published
- 2019
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