High thermoelectric performance in low-cost SnS0.91Se0.09 crystals

Thermoelectric technology allows conversion between heat and electricity. Many good thermoelectric materials contain rare or toxic elements, so developing low-cost and high-performance thermoelectric materials is warranted. Here, we report the temperature-dependent interplay of three separate electronic bands in hole-doped tin sulfide (SnS) crystals. This behavior leads to synergistic optimization between effective mass (m*) and carrier mobility (μ) and can be boosted through introducing selenium (Se). This enhanced the power factor from ~30 to ~53 microwatts per centimeter per square kelvin (μW cm–1 K–2 at 300 K), while lowering the thermal conductivity after Se alloying. As a result, we obtained a maximum figure of merit ZT (ZTmax) of ~1.6 at 873 K and an average ZT (ZTave) of ~1.25 at 300 to 873 K in SnS0.91Se0.09 crystals. Our strategy for band manipulation offers a different route for optimizing thermoelectric performance. The high-performance SnS crystals represent an important step toward low-cost, Earth-abundant, and environmentally friendly thermoelectrics.

Source: ScienceNOW - September 25, 2019 Category: Science Authors: He, W., Wang, D., Wu, H., Xiao, Y., Zhang, Y., He, D., Feng, Y., Hao, Y.-J., Dong, J.-F., Chetty, R., Hao, L., Chen, D., Qin, J., Yang, Q., Li, X., Song, J.-M., Zhu, Y., Xu, W., Niu, C., Li, X., Wang, G., Liu, C., Ohta, M., Pennycook, S. J., He, J., Li, J Tags: Materials Science r-articles Source Type: news