Enhancement of the Thermoelectric Figure of Merit in Blended Cu2Sn1–xZnxS3 Nanobulk Materials

Among the promising waste heat harvesting technologies, thermoelectric materials and devices have attracted considerable interest in recent decades because they offer a promising route to convert waste heat into electrical power. The Cu2Sn1–xZnxS3 system consists of green and abundant elements and exhibits modest thermoelectric performance at a relatively low temperature range. However, the thermoelectric figure of merit, ZT, of Cu2Sn1–xZnxS3 is still too low for practical applications. This study encompasses the bottom-up wet chemical synthesis of Cu2Sn1–xZnxS3 nanoparticles with varying Zn compositions. By blending Cu2Sn0.85Zn0.15S3 and Cu2Sn0.9Zn0.1S3 nanoparticles in a weight fraction of 9:1 to make a nanobulk material, we could achieve a maximum ZT value of 0.64 at 670 K, which is 1.7 and 1.9 times higher than the ZT values of the pristine Cu2Sn0.85Zn0.15S3 and Cu2Sn0.9Zn0.1S3 nanobulk materials, respectively.