Enhanced thermoelectric performance of chloride doped bismuth sulfide prepared by mechanical alloying and spark plasma sintering

• The ZT value of Bi2S3 bulk is achieved 0.6 at 675 K.
• The BiCl3 as donor dopant is effectively improve the electric conductivity of Bi2S3.
• The mechanical alloying and spark plasma sintering decrease the thermal conductivity.
• The solubility of BiCl3 in Bi2S3 is about 1.0 mol%.
• Electric property of BiCl3 doped Bi2S3 indicates semiconductor conducting behavior.

Bi2S3 is a promising thermoelectric material with low cost element of sulfur, but its ZT value is low because of the high electrical resistivity. In the present work, BiCl3 as donor dopant was added to Bi2S3 to improve the carrier content and reduce the electrical resistivity. The mechanical alloying (MA) and spark plasma sintering (SPS) techniques were used to prepare BiCl3 doped Bi2S3 bulk samples. The optimizing carrier content tuned by dopant and the low thermal conductivity controlled by the fabrication process of MA and SPS resulted in the maximum ZT value 0.6 at 675 K for the Bi2S3 bulk doped with 1.0 mol% BiCl3.