The reduction of thermal conductivity in Cd and Sn co-doped Cu3SbSe4-based composites with a secondary-phase CdSe
2021
Deng, Shuping | Jiang, Xianyan | Chʻen, Li-li | Zhang, Ziye | Qi, Ning | Wu, Yichu | Chen, Zhiquan | Tang, Xinfeng
In this paper, we reported the enhanced thermoelectric properties of Cd and Sn dual-doped Cu₃SbSe₄-based material prepared by the vacuum melting combined with spark plasma sintering process. X-ray photoelectron spectroscopy studies revealed the presence of Cu⁺, Cd²⁺, Sb⁵⁺, Sn⁴⁺ and Se²⁻ states of Cu, Cd, Sb, Sn and Se, respectively. All samples exhibited p-type conduction with carrier concentrations varying from 0.54 × 10¹⁸ to 46.42 × 10¹⁸ cm⁻³, while carrier mobility changes from 18.2 to 46.6 cm² V⁻¹ s⁻¹ at room temperature. Cd doping at Cu sites in the Cu₃SbSe₄ can reduce the lattice thermal conductivity, while Sn doping at Sb sites is effective to adjust the carrier concentration. The further reduction in thermal conductivity is observed in Cd-Sn co-doped samples resulting from an accumulated effect combining point defects and the secondary-phase CdSe. Consequently, the maximum dimensionless figure of merit (ZT) value reaches 0.66 at 623 K for the Cu₂.₇₅Cd₀.₂₅Sb₀.₉₄Sn₀.₀₆Se₄ sample, which is 190% larger than that of the intrinsic sample (ZT of 0.35). The findings provide an alternative strategy of boosting the carrier and phonon transports of the Cu₃SbSe₄, which is also a meaningful guidance to achieve high performance in other copper-based chalcogenides.
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