Nanobulk Thermoelectric Materials Fabricated from Chemically Synthesized Cu3Zn1- x Al x SnS5- y Nanocrystals

Pratibha Dwivedi; Masanobu Miyata; Koichi Higashimine; Mari Takahashi; Michihiro Ohta; Korefumi Kubota; Hiroshi Takida; Takeo Akatsuka; Shinya Maenosono

doi:10.1021/acsomega.9b01944

Nanobulk Thermoelectric Materials Fabricated from Chemically Synthesized Cu₃Zn_{1- x} Al _x SnS_{5- y} Nanocrystals

ACS Omega. 2019 Sep 26;4(15):16402-16408. doi: 10.1021/acsomega.9b01944. eCollection 2019 Oct 8.

Authors

Pratibha Dwivedi¹, Masanobu Miyata¹, Koichi Higashimine¹, Mari Takahashi¹, Michihiro Ohta², Korefumi Kubota³, Hiroshi Takida³, Takeo Akatsuka³, Shinya Maenosono¹

Affiliations

¹ School of Materials Science and Center for Nano Materials and Technology, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan.
² Research Institute for Energy Conservation, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 308-8568, Japan.
³ Research Center, Nippon Shokubai Company, Limited, Himeji, Hyogo 671-1292, Japan.

Abstract

Direct energy conversion of heat into electricity using thermoelectric materials is an attractive solution to help address global energy issues. Developing novel materials composed of earth-abundant and nontoxic elements will aid progress toward the goal of sustainable thermoelectric materials. In this study, we chemically synthesized Cu-Zn-Sn-S nanocrystals and fabricated a Cu₃ZnSnS_5-y thermoelectric material using nanocrystals as building blocks. The figure-of-merit (ZT) value of the Cu₃ZnSnS_5-y material was found to be 0.39 at 658 K. We substituted Zn with Al in the Cu₃ZnSnS_5-y system to form Cu₃Zn_1-x Al _x SnS_5-y (x = 0.25, 0.5, 0.75, and 1) to lower the lattice thermal conductivity of the resulting materials. Complete substitution of Al for Zn substantially decreased the lattice thermal conductivity and dramatically increased the electrical conductivity of the material. However, the ZT value could not be significantly enhanced, which could be primarily attributed to the high carrier thermal conductivity. These results highlight the production of Cu₃Zn_1-x Al _x SnS_5-y thermoelectric materials and unveil the scope for improvement of ZT values by altering transport properties.