Bi2S3 is a potential thermoelectric material due to its high Seebeck coefficient (S), low thermal conductivity (κ) and environmentally friendly elemental composition. However, pristine Bi2S3 suffers from a low thermoelectric performance primarily owing to the intrinsic low electrical conductivity (σ). In this work, we employ CeCl3 doping to promote the σ of Bi2S3 by a hydrothermal method. Doping 1.0 % mol CeCl3 provides more electrons to increase the carrier concentration to 2.73 × 1019 cm−3 of Bi2S3 at room temperature, which leads to significant high σ and power factor of 242 μW m−1 K−2 at 573 K. In addition, the formation of micro–nano pores in the doped Bi2S3 bulk samples contribute to the phonon scattering as well as the reduction of lattice thermal conductivity. A peak ZT of ∼0.31 at 623 K is obtained in the Bi2S3 bulk sample doped with 1.0 % mol CeCl3, which is almost twice as high as the pristine Bi2S3. Simultaneously, the Vickers hardness of 1.0 % mol CeCl3 doped Bi2S3 samples achieves to approximately 1.28 GPa, which is enhanced by nearly 40 % compared to pristine Bi2S3. This study has provided a facile method for realizing high thermoelectric performance and high mechanical property of Bi2S3 materials.
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