Thermoelectric Performance of n-Type Magnetic Element Doped Bi2S3

Thermoelectric technology offers great potential for converting waste heat into electrical energy and is an emission-free technique for solid-state cooling. Conventional high-performance thermoelectric materials such as Bi2Te3 and PbTe use rare or toxic elements. Sulfur is an inexpensive and nontoxic alternative to tellurium. However, achieving high efficiencies with Bi2S3 is challenging due to its high electrical resistivity that reduces its power factor. Here, we report Bi2S3 codoped with Cr and Cl to enhance its thermoelectric properties. An enhanced conductivity was achieved due to an increase in the carrier concentration by the substitution of S with Cl. High values of the Seebeck coefficients were obtained despite high carrier concentrations; this is attributed to an increase in the effective mass, resulting from the magnetic drag introduced by the magnetic Cr dopant. A peak power factor of 566 mu W m(-1) K-2 was obtained for a cast sample of Bi2-x/3 Crx/3S3-xClx with x = 0.01 at 320 K, as high as the highest values reported in the literature for sintered samples. These results support the success of codoping thermoelectric materials with isovalent magnetic and carrier concentration tuning elements to enhance the thermoelectric properties of eco-friendly materials.

Automated summary

Thermoelectric technology has the potential to convert waste heat into electricity and is an emission-free solid-state cooling technique. Conventional high-performance thermoelectric materials often use rare or toxic elements, but sulfur can be a cheaper and non-toxic alternative to tellurium. By codoping Bi2S3 with Cr and Cl, the thermoelectric properties were enhanced, with an increase in carrier concentration due to the substitution of S with Cl. The magnetic Cr dopant introduced a magnetic drag that increased the effective mass, resulting in high Seebeck coefficients and power factor.